HP Veritas Volume Manager 5.0 -UX 11i v3 manual Volume resynchronization, Dirty flags

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Understanding Veritas Volume Manager

Volume resynchronization

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Volume resynchronization

When storing data redundantly and using mirrored or RAID-5 volumes, VxVM ensures that all copies of the data match exactly. However, under certain conditions (usually due to complete system failures), some redundant data on a volume can become inconsistent or unsynchronized. The mirrored data is not exactly the same as the original data. Except for normal configuration changes (such as detaching and reattaching a plex), this can only occur when a system crashes while data is being written to a volume.

Data is written to the mirrors of a volume in parallel, as is the data and parity in a RAID-5 volume. If a system crash occurs before all the individual writes complete, it is possible for some writes to complete while others do not. This can result in the data becoming unsynchronized. For mirrored volumes, it can cause two reads from the same region of the volume to return different results, if different mirrors are used to satisfy the read request. In the case of RAID-5 volumes, it can lead to parity corruption and incorrect data reconstruction.

VxVM needs to ensure that all mirrors contain exactly the same data and that the data and parity in RAID-5 volumes agree. This process is called volume resynchronization. For volumes that are part of the disk group that is automatically imported at boot time (usually aliased as the reserved system- wide disk group, bootdg), the resynchronization process takes place when the system reboots.

Not all volumes require resynchronization after a system failure. Volumes that were never written or that were quiescent (that is, had no active I/O) when the system failure occurred could not have had outstanding writes and do not require resynchronization.

Dirty flags

VxVM records when a volume is first written to and marks it as dirty. When a volume is closed by all processes or stopped cleanly by the administrator, and all writes have been completed, VxVM removes the dirty flag for the volume. Only volumes that are marked dirty when the system reboots require resynchronization.

Resynchronization process

The process of resynchronization depends on the type of volume. RAID-5 volumes that contain RAID-5 logs can “replay” those logs. If no logs are available, the volume is placed in reconstruct-recovery mode and all parity is regenerated. For mirrored volumes, resynchronization is done by placing the volume in recovery mode (also called read-writeback recovery mode).

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Contents Veritas Volume Manager Administrator’s Guide Legal Notices Page Contents Booting root volumes Using vxdiskadd to place a disk under control of VxVMVxVM root disk volume restrictions Setting up a VxVM root disk and mirror133 Taking a disk offline 118119 136185 167207 Displaying subdisk information 216 Setting default values for vxassist 241215 217274 252275 289 Moving volumes from a VM disk 290288 290Chapter Creating and administering volume sets 356388 386387 390434 441507 Setup tasks after installation 511463 512521 531 Understanding Veritas Volume Manager Veritas Enterprise Administrator User’s Guide VxVM and the operating system How data is storedHow VxVM handles storage management Physical objects-physical disksDisk arrays Device discovery Multipathed disk arraysOperating system Enclosure-based naming Fibre Channel hub or switch Provide redundant loop access C2t99d0Combining virtual objects in VxVM Virtual objectsVirtual objects in VxVM include the following Connection between objects in VxVM Disk groups VM disksSubdisks Plexes Volumes How VxVM handles storage management Disk01-01 vol06-01 Implementation of non-layered volumes Volume layouts in VxVMImplementation of layered volumes Concatenation and spanning Layout methodsFollowing sections describe each layout method 12 Example of concatenation Data Disk01-01 Example of spanning Data +1 n+2Striping RAID-0 Su1 Su2 Su3 Devname3 Devname2 Mirroring RAID-1 Striping plus mirroring mirrored-stripe or RAID-0+117 Mirrored-stripe volume laid out on six disks Mirroring plus striping striped-mirror, RAID-1+0 or RAID-10Column Mirror Striped plex You need a full license to use this feature Mirror volumesRAID-5 striping with parity Data Parity Traditional RAID-5 arraysVeritas Volume Manager RAID-5 arrays 22 Veritas Volume Manager RAID-5 array Stripe Left-symmetric layoutUnderstanding Veritas Volume Manager RAID-5 logging Layered volumes Example of a striped-mirror layered volume Understanding Veritas Volume Manager Online relayout How online relayout worksThree columns of length 5L/3 Striped volume Limitations of online relayout Transformation characteristics Transformations and volume lengthDirty flags Volume resynchronizationResynchronization process Dirty region logging Dirty region logsLog subdisks and plexes Sequential DRLSmartSync recovery accelerator Data volume configurationVolume snapshots Redo log volume configurationOriginal Space than original Volume Comparison of snapshot featuresUse on creation Requires less storage FastResync FastResync enhancements Non-persistent FastResyncPersistent FastResync DCO volume versioningHow non-persistent FastResync works with snapshots Version 0 DCO volume layout Version 20 DCO volume layoutWhere the size of each map in bytes is How persistent FastResync works with snapshotsDCO FastResync Effect of growing a volume on the FastResync map FastResync limitations Volume sets Hot-relocationVolume sets Administering disks Disk devicesOperating system-based naming Disk device naming in VxVMThere are two different methods of naming disk devices # vxdisk path egrep diskname Private and public disk regions Configured as this disk type. However, it is not a suitable Configures disk access records for them automaticallyTo boot the system.Typically, most disks on a system are Format for boot, root or swap disks, for mirrors orPartial device discovery Discovering and configuring newly added disk devicesFollowing command scans for the devices c1t1d0 and c2t2d0 Next example discovers fabric devicesDisk categories Discovering disks and dynamically adding disk arraysFor more information, see the vxdisk1M manual Enabling discovery of new devices Third-party driver coexistenceAdding support for a new disk array Removing support for a disk array# vxddladm listsupport all Administering the Device Discovery LayerListing details of supported disk arrays # vxddladm listsupport libname=libraryname.slRe-including support for an excluded disk array library Excluding support for a disk array libraryListing excluded disk arrays Listing supported disks in the Disks category Adding unsupported disk arrays to the Disks category# vxdmpadm listenclosure all Length=serialnolength policy=ap# vxddladm addjbod vid=SEAGATE pid=ST318404LSUN18G # vxdisk listAdding foreign devices Removing disks from the Disks category# vxddladm rmjbod vid=SEAGATE Placing disks under VxVM control See Migrating between DMP and HP-UX native multipathing onChanging the disk-naming scheme Mode Format of output from VxVM commandDefault LegacyVxVM vxdmpadm Error V-5-1-10910 Invalid da-name # vxdmpadm getlungroup dmpnodename=disk25Regenerating persistent device names Restart the VxVM configuration demonThis regenerates the persistent name database # vxdmpadm setattr enclosure enclosure tpdmode=nativepseudo Changing device naming for TPD-controlled enclosures# vxdmpadm getsubpaths dmpnodename=enclosure-basedname Persistent simple or nopriv disks in the boot disk group # vxconfigd -kr resetPersistent simple or nopriv disks in non-boot disk groups Installing and formatting disksRe-import the disk group using the following command Add or initialize disks Menu VolumeManager/Disk/AddDisks Displaying and changing default disk layout attributesAdding a disk to VxVM C3t0d0 c3t1d0 c3t2d0 c3t3d0 Exclude disks from hot-relocation use? y,n,q,? default n n Continue operation? y,n,q,? default y yUse default disk names for the disks? y,n,q,? default y Add site tag to disks? y,n,q,? default nEnter desired private region length privlen,q,? default Continue with operation? y,n,q,? default y yEnter the desired format cdsdisk,hpdisk,q,? default cdsdisk Following disksReinitializing a disk Using vxdiskadd to place a disk under control of VxVMAdd or initialize other disks? y,n,q,? default n Vxdiskadm then proceeds to add the disksRootability VxVM root disk volume restrictions Root disk mirrorsSetting up a VxVM root disk and mirror Booting root volumes# /etc/vx/bin/vxcplvmroot -b c0t4d0 # /etc/vx/bin/vxcplvmroot -R 30 -v -b c0t4d0 # /etc/vx/bin/vxcplvmroot -m c1t1d0 -R 30 -v -b c0t4d0Creating an LVM root disk from a VxVM root disk View the changed swap configuration Adding swap volumes to a VxVM rootable systemAdding persistent dump volumes to a VxVM rootable system Display the initial crash dump configuration# crashconf -ds /dev/vx/dsk/bootdg/dumpvol Removing a persistent dump volumeYou can now remove the volume if required Dynamic LUN expansion109 # vxvol -g diskgroup stop volume1 volume2 Removing disksRemoving a disk with subdisks Continue with operation? y,n,q,? default yRemove another disk? y,n,q,? default n VxVM Info V-5-2-268 Removal of disk mydg01 is completeRemoving and replacing disks # /usr/lib/vxvm/bin/vxdiskunsetup c#t#d#Removing a disk from VxVM control Removing a disk with no subdisksTo replace a disk Are you sure you want do this? y,n,q,? default n# vxassist move mkting !mydg02 Following devices are available as replacements c0t1d0 Removing and replacing disksFollowing devices are available as replacements Replacing a failed or removed diskReplace another disk? y,n,q,? default n Enabling a disk Then run the following command on the master nodeSelect a disk device to enable address,list,q,? c0t2d0 # vxreattach -r accesnameDisable another device? y,n,q,? default n Enable another device? y,n,q,? default nTaking a disk offline Renaming a disk You would use the following command to rename the diskReserving disks See the vxedit1M manual page for more information Displaying disk informationVxVM returns a display similar to the following Enter disk device or all address,all,q,? default all List disk information Menu VolumeManager/Disk/ListDiskDisplaying disk information with vxdiskadm To set the Pfto value on a disk, use the following command Controlling Powerfail TimeoutSetting the Pfto values Displaying the Pfto valuesFor example, to disable Pfto on the disk c5t0d6 Enabling or disabling PftoControlling Powerfail Timeout Administering dynamic multipathing DMP How DMP worksHow DMP works Enc00 How DMP monitors I/O on paths Path failover mechanismLoad balancing ThrottlingMigrating between DMP and HP-UX native multipathing Use the following commands to initiate the migrationDMP coexistence with HP-UX native multipathing # vxvol -g diskgroup stopallRestart all the volumes in each disk group # vxvol -g diskgroup startallDMP in a clustered environment Under the new naming scheme asDisabling multipathing and making devices invisible to VxVM Disabling and enabling multipathing for specific devicesEnabling or disabling controllers with shared disk groups Enabling multipathing and making devices visible to VxVM 135 Administering dynamic multipathing DMP Displaying DMP database information Typical output from the vxdisk list command is as followsDisplaying the paths to a disk Disabled Lockrgn Disabled ConfigDisabled Log C1t0d3 state=enabled Type=secondaryRetrieving information about a DMP node Administering DMP using vxdmpadm# vxdmpadm getdmpnode nodename=c3t2d1 # vxdmpadm getlungroup dmpnodename=c11t0d10 Displaying the members of a LUN group# vxdmpadm getdmpnode enclosure=enc0 # vxdmpadm getsubpaths dmpnodename=c2t66d0Displaying information about controllers # vxdmpadm listctlr allDisplaying information about enclosures Following is example output from this commandDisplaying information about array ports Displaying information about TPD-controlled devices # vxdmpadm getsubpaths tpdnodename=emcpower10# vxdmpadm gettpdnode nodename=c7t0d10 To reset the I/O counters to zero, use this command Examples of using the vxdmpadm iostat commandGathering and displaying I/O statistics # vxdmpadm iostat show dmpnodename=c0t0d0 # vxdmpadm iostat start memory=4096# vxdmpadm iostat show pathname=c3t115d0 # vxdmpadm iostat show enclosure=Disk# vxdmpadm setattr path c3t10d0 pathtype=nomanual Setting the attributes of the paths to an enclosure# vxdmpadm setattr path c2t10d0 pathtype=active # vxdmpadm setattr path c1t20d0 pathtype=nopreferredDisplaying the I/O policy Specifying the I/O policy# vxdmpadm setattr enclosure enc1 iopolicy=adaptive Following policies may be setAdaptive Adaptiveminq048 # vxdmpadm setattr arrayname Sena iopolicy=priority This is the default I/O policy for Active/Active A/A arrays# vxdmpadm setattr enclosure Disk iopolicy=minimumq # vxdmpadm setattr arraytype A/A iopolicy=round-robin# vxdmpadm setattr arrayname Disk iopolicy=singleactive Default setting for this attribute is useallpaths=noExample of applying load balancing in a SAN # vxdisk list c3t2d15# dd if=/dev/vx/rdsk/mydg/myvol1 of=/dev/null DMP statistics are now reset# vxdmpadm getattr enclosure ENC0 iopolicy Disabling I/O for paths, controllers or array ports # vxdmpadm -c-fdisable path=pathname# vxdmpadm -c-fdisable ctlr=ctlrname # vxdmpadm setattr enclosure ENC0 iopolicy=singleactiveEnabling I/O for paths, controllers or array ports # vxdmpadm enable path=pathname# vxdmpadm enable ctlr=ctlrname Upgrading disk controller firmwareStop I/O to all disks through one controller of the HBA Re-enable the plex associated with the deviceRenaming an enclosure For the other controller on the HBA, enter# vxdmpadm getattr enclosure enc0 recoveryoption Configuring the response to I/O failures# vxdmpadm setattr \ Configuring the I/O throttling mechanism # vxdmpadm setattr arraytype A/A recoveryoption=default# vxdmpadm setattr enclosure enc0 recoveryoption=nothrottle # vxdmpadm getattr enclosure HDS9500-ALUA0 recoveryoption Displaying recoveryoption valuesHDS9500-ALUA0 Error-Retry Configuring DMP path restoration policies # vxdmpadm start restore interval=seconds policy=checkallDisplaying the status of the DMP path restoration thread Stopping the DMP path restoration threadThis produces output such as the following To add and configure an APM, use the following command Displaying information about the DMP error-handling threadConfiguring array policy modules One daemon should be shown as running# vxdmpadm -r cfgapm modulename Administering DMP using vxdmpadm Creating and administering disk groups Creating and administering disk groups System-wide reserved disk groups Specifying a disk group to commandsBlock special device corresponding to this volume is To nodg# vxdg bootdg Rules for determining the default disk groupDisplaying the system-wide boot disk group See the vxdg1M manual page for more information# vxdg list diskgroup Displaying disk group information# vxdg list # vxdisk -s list devicenameDisplaying free space in a disk group Creating a disk groupFollowing is example output # vxdg init mktdg mktdg01=c1t0d0 Adding a disk to a disk group# vxdiskadd c1t0d0 # vxdg -g diskgroup set cds=onoffRemoving a disk from a disk group # vxdiskunsetup devicename# vxdiskunsetup c1t0d0 # vxdg -g diskgroup rmdisk disknameDeporting a disk group Newdg Importing a disk group# vxdisk -s list Handling disks with duplicated identifiers Select disk group to import group,list,q,? default listSelect another disk group? y,n,q,? default n VxVM Info V-5-2-374 The import of newdg was successful# vxdisk updateudid c2t66d0 c2t67d0 Option to the vxdg import command, as shown in this# vxdisk -f-g diskgroup updateudid disk Writing a new Udid to a disk# vxdisk settag mytaggeddisks c2t66d0 c2t67d0 # vxdg -o useclonedev=on -o updateid import mydg# vxdisk -g diskgroup settag tagname disk # vxdisk listtag# vxdg -q listmeta diskgroup Enabling configuration database copies on tagged disksSample cases of operations on cloned disks # vxdg -o useclonedev=on -o tag=mytaggeddisks import mydgImporting cloned disks without tags # vxdg -g mydg set tagmeta=on tag=t1 nconfig=all nlog=all# vxdisk -o alldgs list To import only the cloned disks into the mydg disk group Symmir command is used to split off the BCV device# /usr/symcli/bin/symmir -g mydg split DEV001 State of the cloned disk is now shown as online clonedisk # vxdg -n newdg -o useclonedev=on -o updateid import mydgImporting cloned disks with tags Disks are tagged as follows# vxdisk set EMC08 clone=off # vxdisk -o alldgs list This command results in output such as the following Renaming a disk groupDgid 774226267.1025.tweety Moving disks between disk groups# vxdg -tC -n newdg import diskgroup # vxrecover -g diskgroup -sb Moving disk groups between systems# vxdisk clearimport devicename Handling errors when importing disksTo clear the locks during import, use the following command # vxdg -C import diskgroupReserving minor numbers for disk groups Following error message indicates a recoverable error# vxdg -f import diskgroup # xvdg init newdg minor=30000 c1d0t0 c1t1d0 # vxprint -g mydg reminorCompatibility of disk groups between platforms # vxdg -g diskgroup set maxdev=4079Handling conflicting configuration copies Example of a serial split brain condition in a cluster191 Typical arrangement of a 2-node campus cluster Automatically Expected a = Expected B =Imported on host Y Correcting conflicting configuration information # vxsplitlines -g newdgReorganizing the contents of disk groups Reorganizing the contents of disk groups 197 Disk group join operation Limitations of disk group split and join Moving DCO volumes between disk groups Listing objects potentially affected by a move201 Split Snapshot Moving objects between disk groups # vxprint # vxdg -o expand move mydg rootdg mydg01Splitting disk groups Following commands would also achieve the same result# vxdg -o expand split rootdg mydg rootdg07 rootdg08 Joining disk groups # vxdg -o overrideverify join sourcedg targetdgMydg Mydg05 C1t96d0 Following command joins disk group mydg to rootdgDisabling a disk group Mydg06 C1t98d0Upgrading a disk group Recovering a destroyed disk groupDestroying a disk group Use the disk group ID to import the disk groupUpgrading a disk group Features supported by disk group versions # vxdg upgrade dgname To list the version of a disk group, use this command# vxdg list dgname Managing the configuration daemon in VxVM # vxdg -T 120 init newdg newdg01=c0t3d0# vxnotify -f Backing up and restoring disk group configuration dataUsing vxnotify to monitor configuration changes # vxnotify -sUsing vxnotify to monitor configuration changes Creating subdisks # vxmake -g mydg sd mydg02-01 mydg02,0,8000# vxprint -st This command provides the following outputDisplaying subdisk information # vxprint -g diskgroup -l subdiskSplitting subdisks Moving subdisks# vxsd -g mydg mv mydg03-01 mydg12-01 mydg12-02 Associating subdisks with plexes Joining subdisks# vxmake -g diskgroup plex plex sd=subdisk # vxsd -g mydg -l 1 assoc vol02-01 mydg11-01 # vxsd -g mydg assoc home-1 mydg02-01 mydg02-00 mydg02-01# vxsd -g mydg -l 4096b assoc vol10-01 mydg15-01 # vxsd -g diskgroup assoc plex subdisk10 ... subdiskMN-1# vxsd -g diskgroup aslog plex subdisk # vxassist -g diskgroup addlog volume diskAssociating log subdisks # vxsd -g mydg aslog vol01-02 mydg02-01Removing subdisks To remove a subdisk, use the following commandDissociating subdisks from plexes Changing subdisk attributes# vxedit -g mydg set comment=subdisk comment mydg02-01 # vxedit -g mydg set putil0=DO-NOT-USE mydg02-01Creating plexes # vxmake -g mydg plex vol01-02 sd=mydg02-01,mydg02-02Displaying plex information Creating a striped plexPlex states Active plex state Clean plex stateDcosnp plex state LOG plex state Empty plex stateIofail plex state Offline plex stateTemp plex state Snaptmp plex stateStale plex state Temprm plex statePlex condition flags Attaching and associating plexes Disabled plex kernel stateEnabled plex kernel state Plex kernel states# vxmend -g diskgroup off plex Taking plexes offline# vxmend -g mydg off vol01-02 vol02-02 Detaching plexes Reattaching plexes# vxvol -g diskgroup start volume Start the volume using the following command# vxmend -g diskgroup fix clean plex Moving plexesDissociating and removing plexes Copying volumes to plexes# vxplex -g diskgroup cp volume newplex # vxplex -g diskgroup -o rm dis plex# vxedit -g mydg set comment=plex comment tutil2=u vol01-02 Changing plex attributes# vxedit -g diskgroup set attribute=value ... plex # vxedit -g mydg set putil0=DO-NOT-USE vol01-02Creating volumes Types of volume layouts RAID-5Supported volume logs and maps Mirror and concatenated-mirror volumesCreating a volume Advanced approachUsing vxassist Assisted approach# vxassist options make volume length attributes VxassistSetting default values for vxassist Following is a sample vxassist defaults file# vxassist -g diskgroup maxsize layout=layout attributes Discovering the maximum size of a volumeDisk group alignment constraints on volumes # vxassist -g dgrp maxsize layout=raid5 nlog=2# vxassist -b make voldefault 10g Creating a volume on any disk# vxassist -b -g diskgroup make volume length # vxprint -g diskgroup -G -F %align# vxassist -b -g mydg make volspec 5g mydg03 mydg04 Creating a volume on specific disks# vxassist -b -g mydg make volspec 5g ctlrc1 !targetc1t5 Specifying ordered allocation of storage to volumes Mydg01 mydg02 mydg03 mydg04 mydg05 mydg06 mydg07 mydg08 Stripe volume Volume across controllers Creating a concatenated-mirror volume Creating a mirrored volumeCreating a mirrored-concatenated volume # vxassist -b -g mydg make volmir 5g layout=mirrorCreating a volume with a version 0 DCO volume # vxvol -g diskgroup set logtype=drldrlseq volume # vxdg -T 90 upgrade diskgroupFor more information, see Upgrading a disk group on Creating a volume with dirty region logging enabled Creating a volume with a version 20 DCO volume# vxdg upgrade diskgroup # vxassist -b -g diskgroup make volume length layout=stripe Creating a striped volume# vxassist -b -g mydg make volzebra 10g layout=stripe Creating a mirrored-stripe volume Creating a striped-mirror volumeMirroring across targets, controllers or enclosures Creating a RAID-5 volume # vxassist -b -g mydg make volraid 10g layout=raid5 nlog=2# vxassist -g diskgroup listtag volume Creating tagged volumes# vxassist -g diskgroup list tag=tagname volume Creating a volume using vxmake Creating a volume using a vxmake description file # vxmake -g diskgroup -d descriptionfile# vxassist -b -g diskgroup make volume length layout=mirror Initializing and starting a volumeMydg04-021/8000,mydg04-031/16000 # vxvol -g diskgroup init active volume Initializing and starting a volume created using vxmake# vxvol -g diskgroup init enable volume # vxvol -g diskgroup init zero volumeAccessing a volume Administering volumes Vxprint command can also be applied to a single disk group Displaying volume informationThis is example output from this command Clean volume state Volume statesActive volume state Empty volume stateNeedsync volume state Volume kernel statesInvalid volume state Replay volume stateEnabled volume kernel state Detached volume kernel stateDisabled volume kernel state Monitoring and controlling tasksManaging tasks with vxtask Vxtask operationsUsing the vxtask command Stopping a volume Putting a volume in maintenance modeAdding a mirror to a volume Starting a volumeTo start all Disabled volumes, enter # /etc/vx/bin/vxmirror -g diskgroup -a Mirroring all volumesMirroring volumes on a VM disk # /etc/vx/bin/vxmirror -d yesRemoving a mirror Mirror volumes on another disk? y,n,q,? default n# vxassist -gdiskgroup remove mirror volume At the following prompt, press Return to make the mirrorAdding logs and maps to volumes Preparing a volume for DRL and instant snapshots Specifying storage for version 20 DCO plexes Determining the DCO version number Using a DCO and DCO volume with a RAID-5 volume# DCONAME=‘vxprint -g diskgroup -F%dconame volume‘ # vxprint -g diskgroup -F%version $DCONAMEThis command returns on if DRL logging is enabled Determining if DRL is enabled on a volumeDetermining if DRL logging is active on a volume Disabling and re-enabling DRLTo re-enable DRL on a volume, enter this command Upgrading existing volumes to use version 20 DCOsTo re-enable sequential DRL on a volume, enter Use the following command on the volume to upgrade it Adding traditional DRL logging to a mirrored volume Removing a traditional DRL log To remove a DRL log, use the vxassist command as follows# vxassist -g mydg addlog volume logtype=drlseq nlog=n # vxassist -g mydg addlog vol03 logtype=drlAdding a RAID-5 log Adding a RAID-5 log using vxplex# vxassist -b -g diskgroup addlog volume loglen=length # vxassist -g mydg addlog volraid# vxassist -g diskgroup maxgrow volume Resizing a volume# vxprint -g diskgroup -ht volume Removing a RAID-5 logVxFS Mounted File System Resizing volumes using vxresizeOnline JFS Full Base JFS Lite Unmounted File SystemExtending to a given length Resizing volumes using vxassistExtending by a given length Shrinking to a given length Resizing volumes using vxvolShrinking by a given length Setting tags on volumes # vxassist -g diskgroup removetag volume tagnameChanging the read policy for mirrored volumes Moving volumes from a VM disk Removing a volumeTo set the read policy to select, use the following command VxVM vxevac Info To move volumes from a diskMove volumes from another disk? y,n,q,? default n VxVM Info V-5-2-188 Evacuation of disk mydg02 is completeEnabling FastResync on a volume # vxvol -g diskgroup set fastresync=on volume# vxprint -g diskgroup -F%hasdcolog volume Checking whether FastResync is enabled on a volume# vxprint -g diskgroup -F%fastresync volume Disabling FastResyncPerforming online relayout # vxassist -g mydg relayout vol02 layout=stripePermitted relayout transformations Relayout to From mirror-concat Concat Supported relayout transformations for RAID-5 volumesRelayout to From raid5 Concat Mirror-concat Mirror-stripeSupported relayout transformations for unmirrored stripe Layered striped-mirror volumesRelayout to From mirror-stripe Concat Relayout to From stripe or stripe-mirror ConcatTagging a relayout operation Specifying a non-default layoutSpecifying a plex for relayout # vxassist -g fsgrp relayout vol04 layout=raid5 ncol=4Viewing the status of a relayout To resume the operation, use the vxtask commandControlling the progress of a relayout # vxrelayout -g mydg -o bg reverse vol04 Converting between layered and non-layered volumes# vxrelayout -g mydg -o bg,slow=1000,iosize=10m start vol04 # vxassist -g mydg relayout vol1 ncol=5# vxassist -g mydg convert vol1 layout=mirror-stripe Converting between layered and non-layered volumes Administering volume snapshots Administering volume snapshots Independent Volume Vxassist snapclear Traditional third-mirror break-off snapshotsTraditional third-mirror break-off snapshots Full-sized instant snapshots 308 Administering volume snapshots Space-optimized instant snapshots Cycle Start Vxsnap make Vxsnap refresh Vxsnap prepareEmulation of third-mirror break-off snapshots Linked break-off snapshot volumes Cascaded snapshots Cascaded snapshotsCreating a snapshot of a snapshot Creating a snapshot of a snapshot Create instant snapshot S2 of S1 Vxsnap make source=S1 Vxsnap dis S2 Restoring the original volume from a snapshot Creating multiple snapshotsRestoring the original volume from a snapshot Creating instant snapshots Creating instant snapshots Preparing to create instant and break-off snapshots Creating a shared cache object # vxcache -g mydg start cobjmydg # LEN=‘vxprint -g diskgroup -F%len volume‘For example to start the cache object, cobjmydg # RSZ=‘vxprint -g diskgroup -F%regionsz $DCONAME‘Creating and managing space-optimized instant snapshots Creating instant snapshots # fsck -F vxfs /dev/vx/rdsk/diskgroup/snapshot # vxsnap -g diskgroup syncwait snapvol Creating and managing full-sized instant snapshots# vxsnap -g mydg make source=myvol/snapvol=snap1myvol # vxsnap -g mydg syncwait snap2myvol# vxprint -gdiskgroup -F%incompletesnapvol Creating and managing third-mirror break-off snapshots # vxsnap -g mydg addmir vol1 nmirror=2 alloc=mydg10,mydg11# vxsnap -g mydg snapwait vol1 nmirror=2 Creating and managing linked break-off snapshot volumes # vxsnap -g diskgroup -b addmir volume mirvol=snapvol \Mirdg=snapdg # vxsnap -g diskgroup make \ Reattach the snapshot volume with the original volume. SeeCreating multiple instant snapshots # vxsnap -g diskgroup make source=vol1/snapvol=snapvol1 \# vxvset -g mydg list vset1 Creating instant snapshots of volume sets# vxvset -g mydg list snapvset1 Svol1 409600 Svol0 204800Svol2 614400 Removing a snapshot mirror Adding snapshot mirrors to a volume# vxsnap -g mydg rmmir vol1 Refreshing an instant snapshot Removing a linked break-off snapshot volumeAdding a snapshot to a cascaded snapshot hierarchy # vxsnap -g mydg rmmir vol1 mirvol=prepsnap mirdg=mysnapdgReattaching an instant snapshot # vxsnap -g mydg reattach snapmyvol source=myvol nmirror=1Reattaching a linked break-off snapshot volume # vxsnap -g mydg snapwait myvol nmirror=1Dissociating an instant snapshot Restoring a volume from an instant snapshot# vxsnap -g mydg restore myvol source=snap3myvol # vxsnap -g snapdg snapwait myvol mirvol=prepsnap# vxsnap -g mydg dis snap2myvol Removing an instant snapshotSplitting an instant snapshot hierarchy # vxedit -g mydg -r rm snap2myvol# vxsnap -g diskgroup print vol Displaying instant snapshot information# vxsnap -g mydg split snap2myvol # vxsnap -g mydg print# vxsnap -g diskgroup -l -v -x list vol # vxsnap -g dg -vx listVxsnap -b -g diskgroup syncstart \ Controlling instant snapshot synchronizationVxsnap -g diskgroup syncresume \ Vxsnap -g diskgroup syncstop vol volsetImproving the performance of snapshot synchronization Listing the snapshots created on a cache# vxcache -g diskgroup listvol cacheobject Tuning the autogrow attributes of a cache # vxcache -g mydg set highwatermark=60 cobjmydgGrowing and shrinking a cache Finally, remove the cache object and its cache volumeRemoving a cache Creating traditional third-mirror break-off snapshots # vxassist -g diskgroup snapwait volume # vxassist -b -g diskgroup snapstart nmirror=N volume# vxassist -g diskgroup snapstart voldef # vxassist -g diskgroup snapshot voldef snapvol Create a snapshot volume using the following command# vxassist -g diskgroup snapshot nmirror=N volume snapshot # vxedit -g diskgroup -rf rm snapshotConverting a plex into a snapshot plex # vxplex -g diskgroup convert state=SNAPDONE plex Reattaching a snapshot volumeCreating multiple snapshots # vxassist -g diskgroup -o allvols snapshot# vxassist -g diskgroup -o allplexes snapback snapshot Adding plexes to a snapshot volume# vxassist -g diskgroup snapback nmirror=number snapshot # vxprint -g diskgroup -F%rid $DCOVOL Dissociating a snapshot volume# vxassist snapclear snapshot Displaying snapshot information Output from this command is shown in the following examples# vxassist snapprint volume # vxassist -g mydg snapprintAdding a version 0 DCO and DCO volume Specifying storage for version 0 DCO plexes # vxdco -g diskgroup -o rm dis dcoobj Removing a version 0 DCO and DCO volume# vxdco -g mydg dis myvoldco For more information, see the vxdco1M manual Reattaching a version 0 DCO and DCO volume# vxdco -g mydg att myvol myvoldco Adding a version 0 DCO and DCO volume Creating and administering volume sets Creating a volume set Adding a volume to a volume setListing details of volume sets Stopping and starting volume sets# vxvset -g diskgroup -f rmvol volset volume Removing a volume from a volume setRaw device node access to component volumes # vxvset -g mydg start set1 # vxvset -g mydg list set1Enabling raw device access when creating a volume set Controlling raw device access for an existing volume set Displaying the raw device access settings for a volume set# vxvset -g diskgroup -fset makedev=onoff vset # vxvset -g mydg set makedev=on myvset2 # vxvset -g mydg set compvolaccess=read-write myvset2# vxvset -g mydg set makedev=off myvset2 Raw device node access to component volumes Configuring off-host processing Implementing off-host processing solutions Example implementation of off-host processingImplementing off-host online backup # vxprint -g volumedg -F%instant volume# vxvol -g volumedg set fastresync=on volume # vxdg import snapvoldg # vxdg deport snapvoldg# fsck -F vxfs /dev/vx/rdsk/snapvoldg/snapvol # vxprint -g volumedg -F%instantvolume # vxsnap -g volumedg snapwait volume mirvol=snapvolImplementing decision support 375 # mount -F vxfs /dev/vx/dsk/snapvoldg/snapvol \ mountpoint You can then resume the procedure from on Implementing off-host processing solutions Administering hot-relocation How hot-relocation works 381 Mydg05 # vxstat -g mydg -s -ff home-02 src-02 # vxrecover -b -g mydg home srcPartial disk failure mail messages Sd mydg01-04 Sd mydg01-06 Sd mydg02-03 Sd mydg02-04How space is chosen for relocation Complete disk failure mail messagesFailing disks mydg02 Configuring a system for hot-relocation # vxdg -g diskgroup spare Displaying spare disk informationMydg mydg02 C0t2d0 658007 Marking a disk as a hot-relocation spare Mark another disk as a spare? y,n,q,? default n# vxedit -g mydg set spare=on mydg01 Excluding a disk from hot-relocation use Where diskname is the disk media nameRemoving a disk from use as a hot-relocation spare Following confirmation is displayedTo use vxdiskadm to exclude a disk from hot-relocation use Making a disk available for hot-relocation use# vxedit -g diskgroup set nohotuse=off diskname Spare=only Configuring hot-relocation to use only spare disksMoving and unrelocating subdisks To root Subject Attempting VxVM relocation on host tealStatus message is displayed at the end of the operation Moving and unrelocating subdisks using vxdiskadmUnrelocate to a new disk y,n,q,? default n Enter the original disk name disk,list,q,?Moving and unrelocating subdisks using vxunreloc Moving and unrelocating subdisks using vxassist# vxassist -g mydg move home !mydg05 mydg02 Moving hot-relocated subdisks back to a different disk Moving hot-relocated subdisks back to their original diskForcing hot-relocated subdisks to accept different offsets Examining which subdisks were hot-relocated from a disk Restarting vxunreloc after errors# vxprint -g mydg -se sdorigdmname=mydg01 # nohup vxrelocd root Nohup vxrelocd -o slow=IOdelay rootModifying the behavior of hot-relocation Nohup vxrelocd root user1 user2See the vxrelocd1M manual page for more information Alternatively, you can use the following command# nohup /etc/vx/bin/vxrelocd root user1 user2 Administering cluster functionality Overview of cluster volume management 399 Example of a 4-node cluster Private and shared disk groups Two types of disk groups are definedReadonly ro Activation modes of shared disk groupsExclusivewrite ew Sharedread srActivation modes for shared disk groups Activation mode DescriptionEnableactivation=true Defaultactivationmode=activation-mode Sharedwrite swConnectivity policy of shared disk groups Global detach policy Local detach policy Disk group failure policy Guidelines for choosing detach and failure policies Effect of disk connectivity on cluster reconfiguration Limitations of shared disk groupsCluster initialization and configuration Cluster reconfiguration# /etc/vx/bin/vxclustadm nodestate state out of cluster Vxclustadm utilityVarious reasons that may be given are shown in Table Reason user initiated stopNode abort messages Reason DescriptionVolume reconfiguration Vxconfigd daemon Vxconfigd daemon recovery# hagrp -freeze group # hagrp -unfreeze groupNode shutdown Node abort Multiple host failover configurationsCluster shutdown Import lock FailoverCorruption of disk group configuration Where the reason can describe errors such asRequesting node status and discovering the master node Administering VxVM in cluster environments# vxdctl -c mode See the vxdctl1M manual page for more informationDetermining if a disk is shareable Example output from this command is displayed hereExample output from this command is as follows Listing shared disk groupsCreating a shared disk group # vxdg -s init diskgroup diskname=devicename# vxdg -s import diskgroup Importing disk groups as sharedForcibly importing a disk group # vxdg -s -f import diskgroupConverting a disk group from shared to private Default disk detach policy is global Changing the activation mode on a shared disk groupSetting the disk detach policy on a shared disk group # vxdg -g diskgroup set activation=mode# vxdg -g diskgroup set dgfailpolicy=dgdisableleave Creating volumes with exclusive open access by a nodeSetting exclusive open access to a volume by a node # vxvol -g dskgrp set exclusive=on volmirDisplaying the cluster protocol version This command produces output similar to the followingThis command produces out put similar to the following Displaying the supported cluster protocol version rangeUpgrading the cluster protocol version Recovering volumes in shared disk groupsObtaining cluster performance statistics Vol Vol1 2421 600000 99.0 # vxstat -bAdministering VxVM in cluster environments Administering Sites and remote mirrors Site-consistent volume with two plexes at each of two sites Example of a two-site configuration with remote storage only Configuring site-based allocation on a disk group Configuring sites for hosts and disksTo remove the site name from a host, use this command # vxdg -g diskgroup set siteconsistent=on Configuring site consistency on a disk groupConfiguring site consistency on a volume # vxdg -g diskgroup set siteconsistent=offSite-based allocation of storage to volumes Setting the siteread policy on a volumeRAID-5 volumes in a site-consistent disk group # vxassist -g diskgroup make volume size mirror=site Examples of storage allocation using sites Command DescriptionRegister a site record for each site with the disk group Turn on site consistency for each volume in the disk groupMaking an existing disk group site consistent Turn on site consistency for the disk groupAutomatic site reattachment Fire drill testing the configurationRecovery from simulated site failure Simulating site failure# ps -afe Failure scenarios and recovery procedures# kill -9 PID Recovery from storage failure Recovery from a loss of site connectivityRecovery from host failure Failure scenario Recovery techniqueRecovery from site failure Failure scenarios and recovery procedures About Storage Expert See the vxse1M manualRunning Storage Expert Before using Storage ExpertHow Storage Expert works One of the following keywords must be specifiedRunning a rule Displaying rule attributes and their default valuesDiscovering what a rule does # vxsestripes2 infoSetting rule attributes Rule result typesIdentifying configuration problems using Storage Expert Recovery timeChecking for non-mirrored RAID-5 logs vxseraid5log3 Checking minimum and maximum RAID-5 log sizes vxseraid5log2Vxseraid5log1 Disk groups Checking disk group configuration copies and logs vxsedg2Checking on disk config size vxsedg3 Checking the version number of disk groups vxsedg4Checking states of plexes and volumes vxsevolplex Checking volume redundancy vxseredundancyChecking for non-imported disk groups vxsedg6 Volumes needing recovery Checking the number of columns in RAID-5 volumes vxseraid5Disk striping Rootability Disk sparing and relocation managementHardware failures System nameChecking the system name vxsehost Rule definitions and attributes Rule Description See Running a rule onRule Attribute Default Description Value Toowideraid5 NsdthresholdVxseraid5 Toonarrowraid5 R5maxsizeVxserootmir Vxseredundancy VolumeredundancyVxsestripes1 Default stripeunit VxsesparesVxsevolplex Rule definitions and attributes Performance guidelines Data assignmentStriping MirroringCombining mirroring and striping RAID-5Volume read policies Performance monitoring Setting performance prioritiesObtaining performance data Printing volume statistics Tracing volume operationsBy vxtrace Using performance data Using I/O statisticsMydg03-03 Archive-01 40960 C1t2d0 Following is an extract from typical output# vxprint -g mydg -tvh archive # vxassist -g mydg move archive !mydg03 destdisk471 General tuning guidelines Tuning VxVMUsing I/O tracing Tuning guidelines for large systems Number of configuration copies for a disk group# vxdmpadm settune dmptunable=value # vxedit set nconfig=5 bigdgChanging the values of tunables # vxdmpadm gettune dmptunableTunable parameters Dmploglevel DmppathswitchblksshiftDmphealthtime DmppathageDmpprobeidlelun DmprestorecyclesDmprestoreinterval DmpqueuedepthDmpscsitimeout DmprestorepolicyDmpretrytimeout DmpretrycountDmpstatinterval VolcheckptdefaultVoldefaultiodelay VolfmrlogszVolmaxio VolmaxvolVolmaxioctl Volmaxspecialio VolmaxparallelioVolsubdisknum Voldrlmaxseqdirty VolcvmsmartsyncVoldrlmaxdrtregs VoldrlminregionszVolioterrbufdflt VoliotiobufdefaultVoliomemmaxpoolsz VoliotiobuflimitVoliotmaxopen VoliotiobufmaxVolpagemodmaxmemsz Volraidminpoolsz VolraidrsrtransmaxTuning VxVM Commands summary If you are using a C shell csh or tcsh, use the commandsVxdg list diskgroup Vxdisk -g diskgroup list diskname# vxdisk -g mydg list # vxdg list mydgTable A-2 Administering disks Command Description # vxedit -g mydg set \ # vxedit -g mydg rename \Mydg03 mydg02 Reserve=on mydg02Spare=off mydg04 # vxdiskunsetup c0t3d0Spare=on mydg04 # vxdisk offline c0t1d0# vxsplitlines -g mydg # vxdg init mydg \Mydg01=c0t1d0 # vxdg -n newdg deport mydgNewdg myvol1 # vxdg -o expand listmove \Mydg newdg myvol1 Newdg myvol2 myvol3# vxmake -g mydg sd \ # vxrecover -g mydg -sb# vxdg destroy mydg Mydg02-01 mydg02,0,8000Mydg11-011 mydg12-012 # vxsd -g mydg assoc \Vol01-01 mydg10-010 \ Mydg02-01Vol01-02 \ # vxsd -g mydg -o rm dis \# vxmake -g mydg plex \ Sd=mydg02-01,mydg02-02# vxplex -g mydg mv \ Vol01-02Vol02-02 vol02-03 Vol03-01 Table A-6 Creating volumes Command Description# vxplex -g mydg cp vol02 \ Vol02-02Stripeunit=W ncol=N attributes Volume length layout=striperaid5 \Vxassist -b -g diskgroup make \ Mysvol 20g layout=stripe \Plex=raidplex,raidlog1,\ # vxmake -g mydg -Uraid5\Vol r5vol \ Raidlog2Table A-7 Administering volumes Command Description Drl=onsequentialoff # vxsnap -gmydg prepare \ myvol drl=onInit=active mydg16 mydg17 # vxassist -g mydg make \Cvol 1g layout=mirror \ Cachevolname=cvolVol3 layout=raid5 \ # vxsnap -g mydg unprepare \ myvol# vxassist -gmydg relayout \ vol2 layout=stripe Stripeunit=16 ncol=4Mytask -b mydg05 # vxrecover -g mydg \# vxassist -g mydg remove \ myvol # vxtask -h -g mydg list# vxtask resume mytask # vxtask pause mytask# vxtask -p -g mydg list # vxtask abort mytaskAdministrative commands Online manual pagesTable A-9 Manual pages Name Description Vxmirror VxrecoverVxmend VxnotifyFile formats Device driver interfacesConfiguring Veritas Volume Manager Setup tasks after installationAdding foreign devices Adding unsupported disk arrays as JBODsAdding disks to disk groups Guidelines for configuring storage Mirroring guidelines Dirty region logging guidelines Striping guidelinesRAID-5 guidelines Hot-relocation guidelines517 Accessing volume devices Configuring cluster supportControlling VxVM’s view of multipathed devices Configuring shared disk groups Converting existing VxVM disk groups to shared disk groupsReconfiguration tasks Glossary Single copy of a configuration database Page See disk enclosure Jbod Page RAID Page Page Page Index CDS Page CVM Page Page DMP Empty Page Page Page Page Iofail 228 Nodarec 228 Nodevice 228 Recover 228 Removed Page Page Page Page Page TPD Page Detached Disabled Enabled Page Page Page Page Page
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