HP HA s Software manual Rules for Mirrored Individual Disks

Page 46

Monitoring Disk Resources

Rules for Using the EMS Disk Monitor with MC/ServiceGuard

Rules for Mirrored Individual Disks

The following rules apply to conﬁguring mirrored disks for use with MC/ServiceGuard and EMS monitoring:

•Mirroring must be PVG-strict.

Mirrored volumes must reside on a different bus from the original volume to avoid a single point of failure and to obtain the best pv_summary value for that mirror. This is done automatically by LVM if you created the PVGs while setting up mirroring. See the lvextend man page and Managing MC/ServiceGuard for more information.

•Logical volumes that are 2-way mirrored should be in separate volume groups from those that are 3-way mirrored.

Putting differently mirrored volumes in the same volume group makes it difﬁcult to accurately interpret the pv_summary data. Take the example of a volume group containing both 2- and 3-way mirroring. If 2 host adapters fail on that volume group, it could mean no data available for the 2-way mirrored logical volume, but one copy still available for the 3-way mirrored volume. The pv_summary would be wrong for one of those mirrored disk conﬁgurations.

•Volume groups representing the same hardware for failover must be created with exactly the same name on all nodes.

For example a bus connecting 3 nodes to a disk array must be deﬁned as part of vg01 on all 3 nodes. We also recommend using the same names for PVGs containing the same actual disks.

Mirrors that have been split off are treated the same by the disk monitor as they are by LVM. When you split off a mirror you may see a change in the following resources:

•/vg/vgName/lv/copies/lvName will be reduced by one when the mirror is split off. If you created a monitoring request for that resource that alerts you when the number of copies changes or is reduced, you may see an event.

•/vg/vgName/lv/status will have a new /lvName resource instance that represents the split off mirror.

•/vg/vgName/lv_summary many change depending on the state of the new logical volume created by the split mirror.

If you restore the split mirror normally using supported LVM commands, the disk monitor will detect the merged mirror and reports

46

Chapter 2

Image 46

Contents Using EMS HA Monitors B5735-90001 AugustLegal Notices Contents Monitoring Cluster Resources Monitoring Network InterfacesMonitoring System Resources TroubleshootingGlossary Contents Printing Date Part Number Edition Printing HistoryB5735-90001 Page Preface PublicationsPage Installing and Using EMS Event Monitoring Services High Availability Monitors What are EMS HA Monitors?Chapter Role of EMS HA Monitors in a High Availability Environment Installing and Removing EMS HA Monitors Installing EMS HA MonitorsRemoving EMS HA Monitors Status AvailMB Using EMS HA MonitorsEvent Monitoring Service Resource Class Hierarchy PvpvlinkEvent Monitoring Service Screen Selecting a Resource to Monitor ScreenUsing Wildcards Creating a Monitoring Request Monitoring Request ParametersHow Do I Tell EMS When to Send Events? What is a Polling Interval? Which Protocols Can I Use to Send Events?What is a Notiﬁcation Comment? Modifying Monitoring Requests Copying Monitoring RequestsRemoving Monitoring Requests Conﬁguring MC/ServiceGuard Package Dependencies Service EMSPackage Conﬁguration Screen Package Resource Dependencies Screen Resource Parameters Screen Using EMS HA Monitors Monitoring Disk Resources Monitoring Disk Resources Disk Monitor Reference Disk Monitor Resource Class HierarchyPhysical Volume Summary Interpreting Physical Volume SummaryDisk Monitor Reference Physical Volume and Physical Volume Link Status Interpreting Physical Volume and Physical Volume Link StatusLogical Volume Summary Interpreting Logical Volume SummaryLogical volume is inactive Logical Volume StatusInterpreting Logical Volume Status Logical volume is DOWN, a complete copy of the data is notLogical Volume Number of Copies Interpreting Logical Volume CopiesRules for Using the EMS Disk Monitor with MC/ServiceGuard Rules for Using the EMS Disk Monitor with MC/ServiceGuard Rules for RAID Arrays Pvsummary Calculations Case Conclusion StateCreating Volume Groups on Disk Arrays Using PV Links Adding PVGs to Existing Volume Groups# mkdir /dev/vgdatabase Creating Logical Volumes Rules for Mirrored Individual Disks Creating Disk Monitoring Requests Disk Monitoring Request Suggestions Parameters When Disks Fail Resources to Monitor for RAID Arrays RAID Array ExamplePvgup Return Resources to Monitor for Mirrored Disks Mirrored Disks ExampleMonitoring Parameters Resource Notify Condition Option Number Pvsummary Valid Meaning Value Devices Resources to Monitor for Lock DisksExample for Interpreting the pvsummary for Mirrored Disks Resource Monitoring Parameters Notify Condition OptionResources to Monitor for Root Volumes Monitoring Cluster Resources Cluster Monitor Resource Class Hierarchy Cluster Monitor ReferenceCluster Cluster Status Interpreting Custer StatusNode Status Interpreting Node StatusPackage Status Interpreting Package StatusCreating Cluster Monitoring Requests Monitoring Network Interfaces Network Monitor Resource Class Hierarchy Network Monitor ReferenceInterpreting LAN Interface Status Chapter 30 sec Net/interfaces/lan/status/LANname When value isConﬁguring Network Monitoring Requests HourMonitoring System Resources System Monitor Reference System Resource Monitor Class HierarchyInterpreting Number of Users Number of UsersResource Name Value Range Interpretation Interpreting Job Queues Job QueuesResource Name Value Interpretation Range Filesystem Available Space Filesystem Available SpaceResource Name Creating System Resource Monitoring Requests 6Troubleshooting EMS Directories and Files Etc/opt/resmon/log Logging and tracing EMS LoggingEMS Tracing Network Performance Issues System Performance IssuesPerformance Considerations Testing Cluster Monitor Requests Testing Monitor RequestsTesting Disk Monitor Requests Testing Network Monitor RequestsMaking Sure Monitors are Running Glossary Notiﬁcation See alert Glossary Glossary Index Index Index