Cascaded snapshots | HP Veritas Volume Manager 5.0 -UX 11i v3

312Administering volume snapshots

Cascaded snapshots

to recover the mirror volume in the same way as for a DISABLED volume. See “Starting a volume” on page 271.

If you resize (that is, grow or shrink) a volume, all its ACTIVE linked mirror volumes are also resized at the same time. The volume and its mirrors can be in the same disk group or in different disk groups. If the operation is successful, the volume and its mirrors will have the same size.

If a volume has been grown, a resynchronization of the grown regions in its linked mirror volumes is started, and the links remain in the ATTACHING state until resynchronization is complete. The vxsnap snapwait command can be used to wait for the state to become ACTIVE.

When you use the vxsnap make command to create the snapshot volume, this removes the link, and establishes a snapshot relationship between the snapshot volume and the original volume.

The vxsnap reattach operation re-establishes the link relationship between the two volumes, and starts a resynchronization of the mirror volume.

See “Creating and managing linked break-off snapshot volumes” on page 331 for details of the procedures for creating and using this type of snapshot.

For information about how to prepare an empty volume for use by full-sized instant snapshots, see “Creating a volume for use as a full-sized instant or linked break-off snapshot” on page 323.

Cascaded snapshots

A snapshot hierarchy known as a snapshot cascade can improve write performance for some applications. Instead of having several independent snapshots of the volume, it is more efficient to make the older snapshots into children of the latest snapshot as shown in Figure 9-4.

Figure 9-4

Snapshot cascade

Original volume

V

Most recent

snapshot

Snapshot

volume

Sn

Snapshot

volume

Sn-1

. . .

Oldest

snapshot

Snapshot

volume

S1

A snapshot may be added to a cascade by specifying the infrontof attribute to the vxsnap make command when the second and subsequent snapshots in the cascade are created. Changes to blocks in the original volume are only written to the most recently created snapshot volume in the cascade. If an attempt is made

Image 311

HP Veritas Volume Manager 5.0 -UX 11i v3 manual Cascaded snapshots

Contents

Veritas Volume Manager Administrator’s Guide Legal Notices Page Contents Setting up a VxVM root disk and mirror Using vxdiskadd to place a disk under control of VxVMVxVM root disk volume restrictions Booting root volumes 136 Taking a disk offline 118119 133 207 167185 217 Setting default values for vxassist 241215 Displaying subdisk information 216 275 252274 290 Moving volumes from a VM disk 290288 289 356 Chapter Creating and administering volume sets 390 386387 388 441 434 512 Setup tasks after installation 511463 507 521 531 Understanding Veritas Volume Manager Veritas Enterprise Administrator User’s Guide How data is stored VxVM and the operating system Physical objects-physical disks How VxVM handles storage management Disk arrays Operating system Multipathed disk arraysDevice discovery Enclosure-based naming Fibre Channel hub or switch C2t99d0 Provide redundant loop access Virtual objects in VxVM include the following Virtual objectsCombining virtual objects in VxVM Connection between objects in VxVM VM disks Disk groups Subdisks Plexes Volumes How VxVM handles storage management Disk01-01 vol06-01 Implementation of layered volumes Volume layouts in VxVMImplementation of non-layered volumes Following sections describe each layout method Layout methodsConcatenation and spanning 12 Example of concatenation Data Disk01-01 +1 n+2 Example of spanning Data Striping RAID-0 Su1 Su2 Su3 Devname3 Devname2 Striping plus mirroring mirrored-stripe or RAID-0+1 Mirroring RAID-1 Mirroring plus striping striped-mirror, RAID-1+0 or RAID-10 17 Mirrored-stripe volume laid out on six disks Column Mirror Striped plex RAID-5 striping with parity Mirror volumesYou need a full license to use this feature Traditional RAID-5 arrays Data Parity Veritas Volume Manager RAID-5 arrays Left-symmetric layout 22 Veritas Volume Manager RAID-5 array Stripe Understanding Veritas Volume Manager RAID-5 logging Layered volumes Example of a striped-mirror layered volume Understanding Veritas Volume Manager How online relayout works Online relayout Three columns of length 5L/3 Striped volume Limitations of online relayout Transformations and volume length Transformation characteristics Resynchronization process Volume resynchronizationDirty flags Dirty region logs Dirty region logging Sequential DRL Log subdisks and plexes Data volume configuration SmartSync recovery accelerator Redo log volume configuration Volume snapshots Original Use on creation Requires less storage Comparison of snapshot featuresSpace than original Volume FastResync Non-persistent FastResync FastResync enhancements How non-persistent FastResync works with snapshots DCO volume versioningPersistent FastResync Version 20 DCO volume layout Version 0 DCO volume layout How persistent FastResync works with snapshots Where the size of each map in bytes is DCO FastResync Effect of growing a volume on the FastResync map FastResync limitations Hot-relocation Volume sets Volume sets Disk devices Administering disks There are two different methods of naming disk devices Disk device naming in VxVMOperating system-based naming # vxdisk path egrep diskname Private and public disk regions Format for boot, root or swap disks, for mirrors or Configures disk access records for them automaticallyTo boot the system.Typically, most disks on a system are Configured as this disk type. However, it is not a suitable Next example discovers fabric devices Discovering and configuring newly added disk devicesFollowing command scans for the devices c1t1d0 and c2t2d0 Partial device discovery For more information, see the vxdisk1M manual Discovering disks and dynamically adding disk arraysDisk categories Removing support for a disk array Third-party driver coexistenceAdding support for a new disk array Enabling discovery of new devices # vxddladm listsupport libname=libraryname.sl Administering the Device Discovery LayerListing details of supported disk arrays # vxddladm listsupport all Listing excluded disk arrays Excluding support for a disk array libraryRe-including support for an excluded disk array library Adding unsupported disk arrays to the Disks category Listing supported disks in the Disks category # vxdisk list Length=serialnolength policy=ap# vxddladm addjbod vid=SEAGATE pid=ST318404LSUN18G # vxdmpadm listenclosure all # vxddladm rmjbod vid=SEAGATE Removing disks from the Disks categoryAdding foreign devices See Migrating between DMP and HP-UX native multipathing on Placing disks under VxVM control Legacy Mode Format of output from VxVM commandDefault Changing the disk-naming scheme # vxdmpadm getlungroup dmpnodename=disk25 VxVM vxdmpadm Error V-5-1-10910 Invalid da-name This regenerates the persistent name database Restart the VxVM configuration demonRegenerating persistent device names # vxdmpadm getsubpaths dmpnodename=enclosure-basedname Changing device naming for TPD-controlled enclosures# vxdmpadm setattr enclosure enclosure tpdmode=nativepseudo # vxconfigd -kr reset Persistent simple or nopriv disks in the boot disk group Re-import the disk group using the following command Installing and formatting disksPersistent simple or nopriv disks in non-boot disk groups Adding a disk to VxVM Displaying and changing default disk layout attributesAdd or initialize disks Menu VolumeManager/Disk/AddDisks C3t0d0 c3t1d0 c3t2d0 c3t3d0 Add site tag to disks? y,n,q,? default n Continue operation? y,n,q,? default y yUse default disk names for the disks? y,n,q,? default y Exclude disks from hot-relocation use? y,n,q,? default n n Following disks Continue with operation? y,n,q,? default y yEnter the desired format cdsdisk,hpdisk,q,? default cdsdisk Enter desired private region length privlen,q,? default Vxdiskadm then proceeds to add the disks Using vxdiskadd to place a disk under control of VxVMAdd or initialize other disks? y,n,q,? default n Reinitializing a disk Rootability Root disk mirrors VxVM root disk volume restrictions # /etc/vx/bin/vxcplvmroot -b c0t4d0 Booting root volumesSetting up a VxVM root disk and mirror # /etc/vx/bin/vxcplvmroot -m c1t1d0 -R 30 -v -b c0t4d0 # /etc/vx/bin/vxcplvmroot -R 30 -v -b c0t4d0 Creating an LVM root disk from a VxVM root disk Display the initial crash dump configuration Adding swap volumes to a VxVM rootable systemAdding persistent dump volumes to a VxVM rootable system View the changed swap configuration Dynamic LUN expansion Removing a persistent dump volumeYou can now remove the volume if required # crashconf -ds /dev/vx/dsk/bootdg/dumpvol 109 Removing disks # vxvol -g diskgroup stop volume1 volume2 VxVM Info V-5-2-268 Removal of disk mydg01 is complete Continue with operation? y,n,q,? default yRemove another disk? y,n,q,? default n Removing a disk with subdisks Removing a disk with no subdisks # /usr/lib/vxvm/bin/vxdiskunsetup c#t#d#Removing a disk from VxVM control Removing and replacing disks # vxassist move mkting !mydg02 Are you sure you want do this? y,n,q,? default nTo replace a disk Removing and replacing disks Following devices are available as replacements c0t1d0 Replacing a failed or removed disk Following devices are available as replacements Replace another disk? y,n,q,? default n # vxreattach -r accesname Then run the following command on the master nodeSelect a disk device to enable address,list,q,? c0t2d0 Enabling a disk Taking a disk offline Enable another device? y,n,q,? default nDisable another device? y,n,q,? default n Reserving disks You would use the following command to rename the diskRenaming a disk VxVM returns a display similar to the following Displaying disk informationSee the vxedit1M manual page for more information Displaying disk information with vxdiskadm List disk information Menu VolumeManager/Disk/ListDiskEnter disk device or all address,all,q,? default all Displaying the Pfto values Controlling Powerfail TimeoutSetting the Pfto values To set the Pfto value on a disk, use the following command Enabling or disabling Pfto For example, to disable Pfto on the disk c5t0d6 Controlling Powerfail Timeout How DMP works Administering dynamic multipathing DMP How DMP works Enc00 Path failover mechanism How DMP monitors I/O on paths Throttling Load balancing # vxvol -g diskgroup stopall Use the following commands to initiate the migrationDMP coexistence with HP-UX native multipathing Migrating between DMP and HP-UX native multipathing # vxvol -g diskgroup startall Restart all the volumes in each disk group Under the new naming scheme as DMP in a clustered environment Enabling or disabling controllers with shared disk groups Disabling and enabling multipathing for specific devicesDisabling multipathing and making devices invisible to VxVM Enabling multipathing and making devices visible to VxVM 135 Administering dynamic multipathing DMP Displaying the paths to a disk Typical output from the vxdisk list command is as followsDisplaying DMP database information C1t0d3 state=enabled Type=secondary Disabled ConfigDisabled Log Disabled Lockrgn # vxdmpadm getdmpnode nodename=c3t2d1 Administering DMP using vxdmpadmRetrieving information about a DMP node # vxdmpadm getsubpaths dmpnodename=c2t66d0 Displaying the members of a LUN group# vxdmpadm getdmpnode enclosure=enc0 # vxdmpadm getlungroup dmpnodename=c11t0d10 # vxdmpadm listctlr all Displaying information about controllers Displaying information about array ports Following is example output from this commandDisplaying information about enclosures # vxdmpadm gettpdnode nodename=c7t0d10 # vxdmpadm getsubpaths tpdnodename=emcpower10Displaying information about TPD-controlled devices Gathering and displaying I/O statistics Examples of using the vxdmpadm iostat commandTo reset the I/O counters to zero, use this command # vxdmpadm iostat show enclosure=Disk # vxdmpadm iostat start memory=4096# vxdmpadm iostat show pathname=c3t115d0 # vxdmpadm iostat show dmpnodename=c0t0d0 # vxdmpadm setattr path c1t20d0 pathtype=nopreferred Setting the attributes of the paths to an enclosure# vxdmpadm setattr path c2t10d0 pathtype=active # vxdmpadm setattr path c3t10d0 pathtype=nomanual Specifying the I/O policy Displaying the I/O policy Adaptiveminq Following policies may be setAdaptive # vxdmpadm setattr enclosure enc1 iopolicy=adaptive 048 # vxdmpadm setattr arraytype A/A iopolicy=round-robin This is the default I/O policy for Active/Active A/A arrays# vxdmpadm setattr enclosure Disk iopolicy=minimumq # vxdmpadm setattr arrayname Sena iopolicy=priority # vxdisk list c3t2d15 Default setting for this attribute is useallpaths=noExample of applying load balancing in a SAN # vxdmpadm setattr arrayname Disk iopolicy=singleactive # vxdmpadm getattr enclosure ENC0 iopolicy DMP statistics are now reset# dd if=/dev/vx/rdsk/mydg/myvol1 of=/dev/null # vxdmpadm setattr enclosure ENC0 iopolicy=singleactive # vxdmpadm -c-fdisable path=pathname# vxdmpadm -c-fdisable ctlr=ctlrname Disabling I/O for paths, controllers or array ports Upgrading disk controller firmware # vxdmpadm enable path=pathname# vxdmpadm enable ctlr=ctlrname Enabling I/O for paths, controllers or array ports For the other controller on the HBA, enter Re-enable the plex associated with the deviceRenaming an enclosure Stop I/O to all disks through one controller of the HBA # vxdmpadm setattr \ Configuring the response to I/O failures# vxdmpadm getattr enclosure enc0 recoveryoption # vxdmpadm setattr arraytype A/A recoveryoption=default Configuring the I/O throttling mechanism # vxdmpadm setattr enclosure enc0 recoveryoption=nothrottle HDS9500-ALUA0 Error-Retry Displaying recoveryoption values# vxdmpadm getattr enclosure HDS9500-ALUA0 recoveryoption # vxdmpadm start restore interval=seconds policy=checkall Configuring DMP path restoration policies This produces output such as the following Stopping the DMP path restoration threadDisplaying the status of the DMP path restoration thread One daemon should be shown as running Displaying information about the DMP error-handling threadConfiguring array policy modules To add and configure an APM, use the following command # vxdmpadm -r cfgapm modulename Administering DMP using vxdmpadm Creating and administering disk groups Creating and administering disk groups To nodg Specifying a disk group to commandsBlock special device corresponding to this volume is System-wide reserved disk groups See the vxdg1M manual page for more information Rules for determining the default disk groupDisplaying the system-wide boot disk group # vxdg bootdg # vxdisk -s list devicename Displaying disk group information# vxdg list # vxdg list diskgroup Following is example output Creating a disk groupDisplaying free space in a disk group # vxdg -g diskgroup set cds=onoff Adding a disk to a disk group# vxdiskadd c1t0d0 # vxdg init mktdg mktdg01=c1t0d0 # vxdg -g diskgroup rmdisk diskname # vxdiskunsetup devicename# vxdiskunsetup c1t0d0 Removing a disk from a disk group Deporting a disk group # vxdisk -s list Importing a disk groupNewdg VxVM Info V-5-2-374 The import of newdg was successful Select disk group to import group,list,q,? default listSelect another disk group? y,n,q,? default n Handling disks with duplicated identifiers Writing a new Udid to a disk Option to the vxdg import command, as shown in this# vxdisk -f-g diskgroup updateudid disk # vxdisk updateudid c2t66d0 c2t67d0 # vxdisk listtag # vxdg -o useclonedev=on -o updateid import mydg# vxdisk -g diskgroup settag tagname disk # vxdisk settag mytaggeddisks c2t66d0 c2t67d0 # vxdg -o useclonedev=on -o tag=mytaggeddisks import mydg Enabling configuration database copies on tagged disksSample cases of operations on cloned disks # vxdg -q listmeta diskgroup # vxdisk -o alldgs list # vxdg -g mydg set tagmeta=on tag=t1 nconfig=all nlog=allImporting cloned disks without tags # /usr/symcli/bin/symmir -g mydg split DEV001 Symmir command is used to split off the BCV deviceTo import only the cloned disks into the mydg disk group Disks are tagged as follows # vxdg -n newdg -o useclonedev=on -o updateid import mydgImporting cloned disks with tags State of the cloned disk is now shown as online clonedisk # vxdisk set EMC08 clone=off # vxdisk -o alldgs list Renaming a disk group This command results in output such as the following # vxdg -tC -n newdg import diskgroup Moving disks between disk groupsDgid 774226267.1025.tweety Moving disk groups between systems # vxrecover -g diskgroup -sb # vxdg -C import diskgroup Handling errors when importing disksTo clear the locks during import, use the following command # vxdisk clearimport devicename # vxdg -f import diskgroup Following error message indicates a recoverable errorReserving minor numbers for disk groups # vxprint -g mydg reminor # xvdg init newdg minor=30000 c1d0t0 c1t1d0 # vxdg -g diskgroup set maxdev=4079 Compatibility of disk groups between platforms Example of a serial split brain condition in a cluster Handling conflicting configuration copies 191 Typical arrangement of a 2-node campus cluster Expected a = Expected B = Automatically Imported on host Y # vxsplitlines -g newdg Correcting conflicting configuration information Reorganizing the contents of disk groups Reorganizing the contents of disk groups 197 Disk group join operation Limitations of disk group split and join Listing objects potentially affected by a move Moving DCO volumes between disk groups 201 Split Snapshot Moving objects between disk groups # vxdg -o expand move mydg rootdg mydg01 # vxprint # vxdg -o expand split rootdg mydg rootdg07 rootdg08 Following commands would also achieve the same resultSplitting disk groups # vxdg -o overrideverify join sourcedg targetdg Joining disk groups Mydg06 C1t98d0 Following command joins disk group mydg to rootdgDisabling a disk group Mydg Mydg05 C1t96d0 Use the disk group ID to import the disk group Recovering a destroyed disk groupDestroying a disk group Upgrading a disk group Upgrading a disk group Features supported by disk group versions # vxdg list dgname To list the version of a disk group, use this command# vxdg upgrade dgname # vxdg -T 120 init newdg newdg01=c0t3d0 Managing the configuration daemon in VxVM # vxnotify -s Backing up and restoring disk group configuration dataUsing vxnotify to monitor configuration changes # vxnotify -f Using vxnotify to monitor configuration changes # vxmake -g mydg sd mydg02-01 mydg02,0,8000 Creating subdisks # vxprint -g diskgroup -l subdisk This command provides the following outputDisplaying subdisk information # vxprint -st # vxsd -g mydg mv mydg03-01 mydg12-01 mydg12-02 Moving subdisksSplitting subdisks # vxmake -g diskgroup plex plex sd=subdisk Joining subdisksAssociating subdisks with plexes # vxsd -g diskgroup assoc plex subdisk10 ... subdiskMN-1 # vxsd -g mydg assoc home-1 mydg02-01 mydg02-00 mydg02-01# vxsd -g mydg -l 4096b assoc vol10-01 mydg15-01 # vxsd -g mydg -l 1 assoc vol02-01 mydg11-01 # vxsd -g mydg aslog vol01-02 mydg02-01 # vxassist -g diskgroup addlog volume diskAssociating log subdisks # vxsd -g diskgroup aslog plex subdisk Changing subdisk attributes To remove a subdisk, use the following commandDissociating subdisks from plexes Removing subdisks # vxedit -g mydg set putil0=DO-NOT-USE mydg02-01 # vxedit -g mydg set comment=subdisk comment mydg02-01 # vxmake -g mydg plex vol01-02 sd=mydg02-01,mydg02-02 Creating plexes Plex states Creating a striped plexDisplaying plex information Dcosnp plex state Clean plex stateActive plex state Offline plex state Empty plex stateIofail plex state LOG plex state Temprm plex state Snaptmp plex stateStale plex state Temp plex state Plex condition flags Plex kernel states Disabled plex kernel stateEnabled plex kernel state Attaching and associating plexes # vxmend -g mydg off vol01-02 vol02-02 Taking plexes offline# vxmend -g diskgroup off plex Reattaching plexes Detaching plexes Moving plexes Start the volume using the following command# vxmend -g diskgroup fix clean plex # vxvol -g diskgroup start volume # vxplex -g diskgroup -o rm dis plex Copying volumes to plexes# vxplex -g diskgroup cp volume newplex Dissociating and removing plexes # vxedit -g mydg set putil0=DO-NOT-USE vol01-02 Changing plex attributes# vxedit -g diskgroup set attribute=value ... plex # vxedit -g mydg set comment=plex comment tutil2=u vol01-02 Creating volumes RAID-5 Types of volume layouts Mirror and concatenated-mirror volumes Supported volume logs and maps Advanced approach Creating a volume Assisted approach Using vxassist Vxassist # vxassist options make volume length attributes Following is a sample vxassist defaults file Setting default values for vxassist # vxassist -g dgrp maxsize layout=raid5 nlog=2 Discovering the maximum size of a volumeDisk group alignment constraints on volumes # vxassist -g diskgroup maxsize layout=layout attributes # vxprint -g diskgroup -G -F %align Creating a volume on any disk# vxassist -b -g diskgroup make volume length # vxassist -b make voldefault 10g # vxassist -b -g mydg make volspec 5g ctlrc1 !targetc1t5 Creating a volume on specific disks# vxassist -b -g mydg make volspec 5g mydg03 mydg04 Specifying ordered allocation of storage to volumes Mydg01 mydg02 mydg03 mydg04 mydg05 mydg06 mydg07 mydg08 Stripe volume Volume across controllers # vxassist -b -g mydg make volmir 5g layout=mirror Creating a mirrored volumeCreating a mirrored-concatenated volume Creating a concatenated-mirror volume Creating a volume with a version 0 DCO volume For more information, see Upgrading a disk group on # vxdg -T 90 upgrade diskgroup# vxvol -g diskgroup set logtype=drldrlseq volume # vxdg upgrade diskgroup Creating a volume with a version 20 DCO volumeCreating a volume with dirty region logging enabled # vxassist -b -g mydg make volzebra 10g layout=stripe Creating a striped volume# vxassist -b -g diskgroup make volume length layout=stripe Creating a striped-mirror volume Creating a mirrored-stripe volume Mirroring across targets, controllers or enclosures # vxassist -b -g mydg make volraid 10g layout=raid5 nlog=2 Creating a RAID-5 volume # vxassist -g diskgroup list tag=tagname volume Creating tagged volumes# vxassist -g diskgroup listtag volume Creating a volume using vxmake # vxmake -g diskgroup -d descriptionfile Creating a volume using a vxmake description file Mydg04-021/8000,mydg04-031/16000 Initializing and starting a volume# vxassist -b -g diskgroup make volume length layout=mirror # vxvol -g diskgroup init zero volume Initializing and starting a volume created using vxmake# vxvol -g diskgroup init enable volume # vxvol -g diskgroup init active volume Accessing a volume Administering volumes This is example output from this command Displaying volume informationVxprint command can also be applied to a single disk group Empty volume state Volume statesActive volume state Clean volume state Replay volume state Volume kernel statesInvalid volume state Needsync volume state Monitoring and controlling tasks Detached volume kernel stateDisabled volume kernel state Enabled volume kernel state Vxtask operations Managing tasks with vxtask Using the vxtask command Putting a volume in maintenance mode Stopping a volume To start all Disabled volumes, enter Starting a volumeAdding a mirror to a volume # /etc/vx/bin/vxmirror -d yes Mirroring all volumesMirroring volumes on a VM disk # /etc/vx/bin/vxmirror -g diskgroup -a At the following prompt, press Return to make the mirror Mirror volumes on another disk? y,n,q,? default n# vxassist -gdiskgroup remove mirror volume Removing a mirror Adding logs and maps to volumes Preparing a volume for DRL and instant snapshots Specifying storage for version 20 DCO plexes # vxprint -g diskgroup -F%version $DCONAME Using a DCO and DCO volume with a RAID-5 volume# DCONAME=‘vxprint -g diskgroup -F%dconame volume‘ Determining the DCO version number Disabling and re-enabling DRL Determining if DRL is enabled on a volumeDetermining if DRL logging is active on a volume This command returns on if DRL logging is enabled To re-enable sequential DRL on a volume, enter Upgrading existing volumes to use version 20 DCOsTo re-enable DRL on a volume, enter this command Use the following command on the volume to upgrade it Adding traditional DRL logging to a mirrored volume # vxassist -g mydg addlog vol03 logtype=drl To remove a DRL log, use the vxassist command as follows# vxassist -g mydg addlog volume logtype=drlseq nlog=n Removing a traditional DRL log # vxassist -g mydg addlog volraid Adding a RAID-5 log using vxplex# vxassist -b -g diskgroup addlog volume loglen=length Adding a RAID-5 log Removing a RAID-5 log Resizing a volume# vxprint -g diskgroup -ht volume # vxassist -g diskgroup maxgrow volume Unmounted File System Resizing volumes using vxresizeOnline JFS Full Base JFS Lite VxFS Mounted File System Extending by a given length Resizing volumes using vxassistExtending to a given length Shrinking by a given length Resizing volumes using vxvolShrinking to a given length # vxassist -g diskgroup removetag volume tagname Setting tags on volumes Changing the read policy for mirrored volumes To set the read policy to select, use the following command Removing a volumeMoving volumes from a VM disk VxVM Info V-5-2-188 Evacuation of disk mydg02 is complete To move volumes from a diskMove volumes from another disk? y,n,q,? default n VxVM vxevac Info # vxvol -g diskgroup set fastresync=on volume Enabling FastResync on a volume Disabling FastResync Checking whether FastResync is enabled on a volume# vxprint -g diskgroup -F%fastresync volume # vxprint -g diskgroup -F%hasdcolog volume # vxassist -g mydg relayout vol02 layout=stripe Performing online relayout Permitted relayout transformations Mirror-concat Mirror-stripe Supported relayout transformations for RAID-5 volumesRelayout to From raid5 Concat Relayout to From mirror-concat Concat Relayout to From stripe or stripe-mirror Concat Layered striped-mirror volumesRelayout to From mirror-stripe Concat Supported relayout transformations for unmirrored stripe # vxassist -g fsgrp relayout vol04 layout=raid5 ncol=4 Specifying a non-default layoutSpecifying a plex for relayout Tagging a relayout operation Controlling the progress of a relayout To resume the operation, use the vxtask commandViewing the status of a relayout # vxassist -g mydg relayout vol1 ncol=5 Converting between layered and non-layered volumes# vxrelayout -g mydg -o bg,slow=1000,iosize=10m start vol04 # vxrelayout -g mydg -o bg reverse vol04 # vxassist -g mydg convert vol1 layout=mirror-stripe Converting between layered and non-layered volumes Administering volume snapshots Administering volume snapshots Traditional third-mirror break-off snapshots Independent Volume Vxassist snapclear Traditional third-mirror break-off snapshots Full-sized instant snapshots 308 Administering volume snapshots Cycle Start Vxsnap make Vxsnap refresh Vxsnap prepare Space-optimized instant snapshots Emulation of third-mirror break-off snapshots Linked break-off snapshot volumes Cascaded snapshots Cascaded snapshots Creating a snapshot of a snapshot Creating a snapshot of a snapshot Create instant snapshot S2 of S1 Vxsnap make source=S1 Vxsnap dis S2 Creating multiple snapshots Restoring the original volume from a snapshot Restoring 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 # RSZ=‘vxprint -g diskgroup -F%regionsz $DCONAME‘ # LEN=‘vxprint -g diskgroup -F%len volume‘For example to start the cache object, cobjmydg # vxcache -g mydg start cobjmydg Creating and managing space-optimized instant snapshots Creating instant snapshots # fsck -F vxfs /dev/vx/rdsk/diskgroup/snapshot # vxsnap -g mydg syncwait snap2myvol Creating and managing full-sized instant snapshots# vxsnap -g mydg make source=myvol/snapvol=snap1myvol # vxsnap -g diskgroup syncwait snapvol # vxprint -gdiskgroup -F%incompletesnapvol # vxsnap -g mydg addmir vol1 nmirror=2 alloc=mydg10,mydg11 Creating and managing third-mirror break-off snapshots # vxsnap -g mydg snapwait vol1 nmirror=2 # vxsnap -g diskgroup -b addmir volume mirvol=snapvol \ Creating and managing linked break-off snapshot volumes Mirdg=snapdg # vxsnap -g diskgroup make source=vol1/snapvol=snapvol1 \ Reattach the snapshot volume with the original volume. SeeCreating multiple instant snapshots # vxsnap -g diskgroup make \ # vxvset -g mydg list snapvset1 Creating instant snapshots of volume sets# vxvset -g mydg list vset1 Svol2 614400 Svol0 204800Svol1 409600 # vxsnap -g mydg rmmir vol1 Adding snapshot mirrors to a volumeRemoving a snapshot mirror # vxsnap -g mydg rmmir vol1 mirvol=prepsnap mirdg=mysnapdg Removing a linked break-off snapshot volumeAdding a snapshot to a cascaded snapshot hierarchy Refreshing an instant snapshot # vxsnap -g mydg reattach snapmyvol source=myvol nmirror=1 Reattaching an instant snapshot # vxsnap -g mydg snapwait myvol nmirror=1 Reattaching a linked break-off snapshot volume # vxsnap -g snapdg snapwait myvol mirvol=prepsnap Restoring a volume from an instant snapshot# vxsnap -g mydg restore myvol source=snap3myvol Dissociating an instant snapshot # vxedit -g mydg -r rm snap2myvol Removing an instant snapshotSplitting an instant snapshot hierarchy # vxsnap -g mydg dis snap2myvol # vxsnap -g mydg print Displaying instant snapshot information# vxsnap -g mydg split snap2myvol # vxsnap -g diskgroup print vol # vxsnap -g dg -vx list # vxsnap -g diskgroup -l -v -x list vol Vxsnap -g diskgroup syncstop vol volset Controlling instant snapshot synchronizationVxsnap -g diskgroup syncresume \ Vxsnap -b -g diskgroup syncstart \ # vxcache -g diskgroup listvol cacheobject Listing the snapshots created on a cacheImproving the performance of snapshot synchronization # vxcache -g mydg set highwatermark=60 cobjmydg Tuning the autogrow attributes of a cache Removing a cache Finally, remove the cache object and its cache volumeGrowing and shrinking a cache Creating traditional third-mirror break-off snapshots # vxassist -g diskgroup snapstart voldef # vxassist -b -g diskgroup snapstart nmirror=N volume# vxassist -g diskgroup snapwait volume # vxedit -g diskgroup -rf rm snapshot Create a snapshot volume using the following command# vxassist -g diskgroup snapshot nmirror=N volume snapshot # vxassist -g diskgroup snapshot voldef snapvol Converting a plex into a snapshot plex # vxassist -g diskgroup -o allvols snapshot Reattaching a snapshot volumeCreating multiple snapshots # vxplex -g diskgroup convert state=SNAPDONE plex # vxassist -g diskgroup snapback nmirror=number snapshot Adding plexes to a snapshot volume# vxassist -g diskgroup -o allplexes snapback snapshot # vxassist snapclear snapshot Dissociating a snapshot volume# vxprint -g diskgroup -F%rid $DCOVOL # vxassist -g mydg snapprint Output from this command is shown in the following examples# vxassist snapprint volume Displaying snapshot information Adding a version 0 DCO and DCO volume Specifying storage for version 0 DCO plexes # vxdco -g mydg dis myvoldco Removing a version 0 DCO and DCO volume# vxdco -g diskgroup -o rm dis dcoobj # vxdco -g mydg att myvol myvoldco Reattaching a version 0 DCO and DCO volumeFor more information, see the vxdco1M manual Adding a version 0 DCO and DCO volume Creating and administering volume sets Adding a volume to a volume set Creating a volume set Stopping and starting volume sets Listing details of volume sets # vxvset -g mydg start set1 # vxvset -g mydg list set1 Removing a volume from a volume setRaw device node access to component volumes # vxvset -g diskgroup -f rmvol volset volume Enabling raw device access when creating a volume set # vxvset -g diskgroup -fset makedev=onoff vset Displaying the raw device access settings for a volume setControlling raw device access for an existing volume set # vxvset -g mydg set makedev=off myvset2 # vxvset -g mydg set compvolaccess=read-write myvset2# vxvset -g mydg set makedev=on myvset2 Raw device node access to component volumes Configuring off-host processing Example implementation of off-host processing Implementing off-host processing solutions # vxprint -g volumedg -F%instant volume Implementing off-host online backup # vxvol -g volumedg set fastresync=on volume # fsck -F vxfs /dev/vx/rdsk/snapvoldg/snapvol # vxdg deport snapvoldg# vxdg import snapvoldg Implementing decision support # vxsnap -g volumedg snapwait volume mirvol=snapvol# vxprint -g volumedg -F%instantvolume 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 Sd mydg01-04 Sd mydg01-06 Sd mydg02-03 Sd mydg02-04 # vxrecover -b -g mydg home srcPartial disk failure mail messages # vxstat -g mydg -s -ff home-02 src-02 Failing disks mydg02 Complete disk failure mail messagesHow space is chosen for relocation Configuring a system for hot-relocation Mydg mydg02 C0t2d0 658007 Displaying spare disk information# vxdg -g diskgroup spare # vxedit -g mydg set spare=on mydg01 Mark another disk as a spare? y,n,q,? default nMarking a disk as a hot-relocation spare Following confirmation is displayed Where diskname is the disk media nameRemoving a disk from use as a hot-relocation spare Excluding a disk from hot-relocation use # vxedit -g diskgroup set nohotuse=off diskname Making a disk available for hot-relocation useTo use vxdiskadm to exclude a disk from hot-relocation use To root Subject Attempting VxVM relocation on host teal Configuring hot-relocation to use only spare disksMoving and unrelocating subdisks Spare=only Enter the original disk name disk,list,q,? Moving and unrelocating subdisks using vxdiskadmUnrelocate to a new disk y,n,q,? default n Status message is displayed at the end of the operation # vxassist -g mydg move home !mydg05 mydg02 Moving and unrelocating subdisks using vxassistMoving and unrelocating subdisks using vxunreloc Forcing hot-relocated subdisks to accept different offsets Moving hot-relocated subdisks back to their original diskMoving hot-relocated subdisks back to a different disk # vxprint -g mydg -se sdorigdmname=mydg01 Restarting vxunreloc after errorsExamining which subdisks were hot-relocated from a disk Nohup vxrelocd root user1 user2 Nohup vxrelocd -o slow=IOdelay rootModifying the behavior of hot-relocation # nohup vxrelocd root # nohup /etc/vx/bin/vxrelocd root user1 user2 Alternatively, you can use the following commandSee the vxrelocd1M manual page for more information Administering cluster functionality Overview of cluster volume management 399 Example of a 4-node cluster Two types of disk groups are defined Private and shared disk groups Sharedread sr Activation modes of shared disk groupsExclusivewrite ew Readonly ro Sharedwrite sw Activation mode DescriptionEnableactivation=true Defaultactivationmode=activation-mode Activation modes for shared disk groups Connectivity policy of shared disk groups Global detach policy Local detach policy Disk group failure policy Guidelines for choosing detach and failure policies Limitations of shared disk groups Effect of disk connectivity on cluster reconfiguration Cluster reconfiguration Cluster initialization and configuration Reason user initiated stop Vxclustadm utilityVarious reasons that may be given are shown in Table # /etc/vx/bin/vxclustadm nodestate state out of cluster Reason Description Node abort messages Volume reconfiguration Vxconfigd daemon recovery Vxconfigd daemon # hagrp -unfreeze group # hagrp -freeze group Node shutdown Cluster shutdown Multiple host failover configurationsNode abort Failover Import lock Where the reason can describe errors such as Corruption of disk group configuration See the vxdctl1M manual page for more information Administering VxVM in cluster environments# vxdctl -c mode Requesting node status and discovering the master node Listing shared disk groups Example output from this command is displayed hereExample output from this command is as follows Determining if a disk is shareable # vxdg -s init diskgroup diskname=devicename Creating a shared disk group # vxdg -s -f import diskgroup Importing disk groups as sharedForcibly importing a disk group # vxdg -s import diskgroup Converting a disk group from shared to private # vxdg -g diskgroup set activation=mode Changing the activation mode on a shared disk groupSetting the disk detach policy on a shared disk group Default disk detach policy is global # vxvol -g dskgrp set exclusive=on volmir Creating volumes with exclusive open access by a nodeSetting exclusive open access to a volume by a node # vxdg -g diskgroup set dgfailpolicy=dgdisableleave Displaying the supported cluster protocol version range This command produces output similar to the followingThis command produces out put similar to the following Displaying the cluster protocol version Obtaining cluster performance statistics Recovering volumes in shared disk groupsUpgrading the cluster protocol version # vxstat -b Vol Vol1 2421 600000 99.0 Administering 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 To remove the site name from a host, use this command Configuring sites for hosts and disksConfiguring site-based allocation on a disk group # vxdg -g diskgroup set siteconsistent=off Configuring site consistency on a disk groupConfiguring site consistency on a volume # vxdg -g diskgroup set siteconsistent=on RAID-5 volumes in a site-consistent disk group Setting the siteread policy on a volumeSite-based allocation of storage to volumes # vxassist -g diskgroup make volume size mirror=site Command Description Examples of storage allocation using sites Turn on site consistency for the disk group Turn on site consistency for each volume in the disk groupMaking an existing disk group site consistent Register a site record for each site with the disk group Simulating site failure Fire drill testing the configurationRecovery from simulated site failure Automatic site reattachment # kill -9 PID Failure scenarios and recovery procedures# ps -afe Failure scenario Recovery technique Recovery from a loss of site connectivityRecovery from host failure Recovery from storage failure Recovery from site failure Failure scenarios and recovery procedures See the vxse1M manual About Storage Expert One of the following keywords must be specified Before using Storage ExpertHow Storage Expert works Running Storage Expert # vxsestripes2 info Displaying rule attributes and their default valuesDiscovering what a rule does Running a rule Rule result types Setting rule attributes Recovery time Identifying configuration problems using Storage Expert Vxseraid5log1 Checking minimum and maximum RAID-5 log sizes vxseraid5log2Checking for non-mirrored RAID-5 logs vxseraid5log3 Checking the version number of disk groups vxsedg4 Checking disk group configuration copies and logs vxsedg2Checking on disk config size vxsedg3 Disk groups Checking for non-imported disk groups vxsedg6 Checking volume redundancy vxseredundancyChecking states of plexes and volumes vxsevolplex Disk striping Checking the number of columns in RAID-5 volumes vxseraid5Volumes needing recovery System name Disk sparing and relocation managementHardware failures Rootability Checking the system name vxsehost Rule definitions and attributes See Running a rule on Rule Description Rule Attribute Default Description Value R5maxsize NsdthresholdVxseraid5 Toonarrowraid5 Toowideraid5 Vxsespares Vxseredundancy VolumeredundancyVxsestripes1 Default stripeunit Vxserootmir Vxsevolplex Rule definitions and attributes Data assignment Performance guidelines Mirroring Striping RAID-5 Combining mirroring and striping Volume read policies Obtaining performance data Setting performance prioritiesPerformance monitoring By vxtrace Tracing volume operationsPrinting volume statistics Using I/O statistics Using performance data # vxassist -g mydg move archive !mydg03 destdisk Following is an extract from typical output# vxprint -g mydg -tvh archive Mydg03-03 Archive-01 40960 C1t2d0 471 Using I/O tracing Tuning VxVMGeneral tuning guidelines Number of configuration copies for a disk group Tuning guidelines for large systems # vxdmpadm gettune dmptunable # vxedit set nconfig=5 bigdgChanging the values of tunables # vxdmpadm settune dmptunable=value Tunable parameters Dmppathage DmppathswitchblksshiftDmphealthtime Dmploglevel Dmpqueuedepth DmprestorecyclesDmprestoreinterval Dmpprobeidlelun Dmpretrycount DmprestorepolicyDmpretrytimeout Dmpscsitimeout Volfmrlogsz VolcheckptdefaultVoldefaultiodelay Dmpstatinterval Volmaxioctl VolmaxvolVolmaxio Volsubdisknum VolmaxparallelioVolmaxspecialio Voldrlminregionsz VolcvmsmartsyncVoldrlmaxdrtregs Voldrlmaxseqdirty Voliotiobuflimit VoliotiobufdefaultVoliomemmaxpoolsz Volioterrbufdflt Volpagemodmaxmemsz VoliotiobufmaxVoliotmaxopen Volraidrsrtransmax Volraidminpoolsz Tuning VxVM If you are using a C shell csh or tcsh, use the commands Commands summary # vxdg list mydg Vxdisk -g diskgroup list diskname# vxdisk -g mydg list Vxdg list diskgroup Table A-2 Administering disks Command Description Reserve=on mydg02 # vxedit -g mydg rename \Mydg03 mydg02 # vxedit -g mydg set \ # vxdisk offline c0t1d0 # vxdiskunsetup c0t3d0Spare=on mydg04 Spare=off mydg04 # vxdg -n newdg deport mydg # vxdg init mydg \Mydg01=c0t1d0 # vxsplitlines -g mydg Newdg myvol2 myvol3 # vxdg -o expand listmove \Mydg newdg myvol1 Newdg myvol1 Mydg02-01 mydg02,0,8000 # vxrecover -g mydg -sb# vxdg destroy mydg # vxmake -g mydg sd \ Mydg02-01 # vxsd -g mydg assoc \Vol01-01 mydg10-010 \ Mydg11-011 mydg12-012 Sd=mydg02-01,mydg02-02 # vxsd -g mydg -o rm dis \# vxmake -g mydg plex \ Vol01-02 \ Vol02-02 vol02-03 Vol01-02# vxplex -g mydg mv \ Vol02-02 Table A-6 Creating volumes Command Description# vxplex -g mydg cp vol02 \ Vol03-01 Mysvol 20g layout=stripe \ Volume length layout=striperaid5 \Vxassist -b -g diskgroup make \ Stripeunit=W ncol=N attributes Raidlog2 # vxmake -g mydg -Uraid5\Vol r5vol \ Plex=raidplex,raidlog1,\ Table A-7 Administering volumes Command Description # vxsnap -gmydg prepare \ myvol drl=on Drl=onsequentialoff Cachevolname=cvol # vxassist -g mydg make \Cvol 1g layout=mirror \ Init=active mydg16 mydg17 Stripeunit=16 ncol=4 # vxsnap -g mydg unprepare \ myvol# vxassist -gmydg relayout \ vol2 layout=stripe Vol3 layout=raid5 \ # vxtask -h -g mydg list # vxrecover -g mydg \# vxassist -g mydg remove \ myvol Mytask -b mydg05 # vxtask abort mytask # vxtask pause mytask# vxtask -p -g mydg list # vxtask resume mytask Online manual pages Administrative commands Table A-9 Manual pages Name Description Vxnotify VxrecoverVxmend Vxmirror Device driver interfaces File formats Setup tasks after installation Configuring Veritas Volume Manager Adding disks to disk groups Adding unsupported disk arrays as JBODsAdding foreign devices Guidelines for configuring storage Mirroring guidelines Striping guidelines Dirty region logging guidelines Hot-relocation guidelines RAID-5 guidelines 517 Controlling VxVM’s view of multipathed devices Configuring cluster supportAccessing volume devices Converting existing VxVM disk groups to shared disk groups Configuring shared disk groups Reconfiguration 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