Using EMS HA Monitors

Chapter 2 39
Monitoring Disk Resources
Disk Monitor Reference
Logical Volume Number of Copies
The logical volume number of copies is most useful to monitor in a mirrored disk
configuration. It tells you how many copies of the data are available.
MirrorDisk/UX supports up to 3-way mirroring, so there can be from 0 to 3 copies
(see Table 2-5.) In a RAID configuration that is not mirrored using LVM, the only
possible number is 0 or 1; either the data is accessible or it isn’t.
Note that when you configure mirroring in LVM, it lists 0 mirrors to mean you have
one copy of the data. Likewise, 2 mirrors mean you have 3 copies of the data (one
original plus 2 mirrors). The disk monitor is monitoring all copies of data, and
therefore counts the “original” as part of the total number of copies.
Table 2-5 Interpreting Logical Volume Copies
When configuring requests from the SAM interface, a wildcard (*) may be used in
place of lvName to request status for all logical volumes in a volume group.
If you split off mirrors from your mirrored configuration, you will see the number of
copies reduced by 1 when the split mirror is created.
Resource Name vg/vgName/lv/copies/lvName
Condition Interpretation
0 No copies, either physical parts of the disk array have problems,
the lv is inactive, or a physical extent is stale or unavailable.
1 One complete copy of data available; if the data is not mirrored,
then all physical extents are fine, if data is mirrored, all other
copies have problems.
2 Two complete copies of data are available; if the data is two-way
mirrored, then all physical disks are up and data is available, if
3-way mirrored, at least one logical extent has a missing or stale
physical extent .
3 All copies of a 3-way mirror are available.