The XVM Volume Manager can maintain statistics for physvols, subvolumes, stripes, concats, mirrors, and slices.
You use the stat option of the change command to turn statistics off and on and to reset the statistics for a volume element. Statistics are on by default. When you turn statistics on with the change command, statistics are collected only for the layer you specify. If you want to collect statistics for more than one layer of an XVM logical volume, you must specify each layer explicitly.
In a clustered environment, statistics are maintained for the local node only.
Statistics for all volume elements and physvols show the number of read and write operations as well as the number of 512-byte blocks read and written. The following sections describe the specific statistics for each type of volume element:
The following example displays the results of a show command to display the statistics of a physical volume for which statistics have been turned on:
xvm:cluster> show -stat betty Local stats for phys/betty since being enabled or reset: ---------------------------------------------------------------------- client read requests: 3 client write requests: 42 client 512 byte blks read: 257 client 512 byte blks written: 4681 |
The following example displays the results of a show command to display the statistics of a subvolume for which statistics have been turned on:
xvm:cluster> show -stat tinyvol/data Local stats for subvol/tinyvol/data since being enabled or reset: ---------------------------------------------------------------------- read requests: 12 write requests: 109 512 byte blks read: 1034 512 byte blks written: 9533 |
Stripe statistics show the size of the operations versus the size of the stripe width and whether the operations are aligned on a 512-byte boundary. The best performance is obtained when the greatest number of requests are aligned at both start and end.
The following example displays the results of a show command on a stripe for which statistics have been turned on:
xvm:cluster> show -v stripe/stripe0
XVM ve stripe/stripe0
========================
volname: vol/cxfsvol subvolume: subvol/cxfsvol/data
size: 35557888 iou: 1 pieces: 2 open: no
state: 0xa (valid,online) user-flags: online,autoname
uuid: 31350c60-7aa4-1022-85f1-0800690592c9
tid: 922806085 (03/30/99_09:01:25)
Type-specific information:
---------------------------
stripe unit size: 128
Local stats for stripe/stripe0 since being enabled or reset:
-----------------------------------------------------------------------
read requests: 1826
write requests: 0
512 byte blks read: 15236
512 byte blks written: 0
Requests aligned at both start and end
equal to stripe width: 10
greater than stripe width: 10
less than stripe width: 0
Requests aligned at start
greater than stripe width: 0
less than stripe width: 20
Requests aligned at end
greater than stripe width: 0
less than stripe width: 19
Requests unaligned
equal to stripe width: 0
greater than stripe width: 0
less than stripe width: 1767
Pieces:
# Size Timestamp Type/Name State
-----------------------------------------------------------
0 17779016 03/30/99_09:00:49 slice/cxfsdsk1s0 valid,online
1 17779016 03/30/99_09:01:01 slice/cxfsdsk2s0 valid,online
|
Concat statistics show the number of operations that are straddled, which are operations that cross the boundary between one piece and the next.
The following example displays the results of a show command on a concat for which statistics have been turned on:
xvm:cluster> show -v concat/concat3 XVM ve concat/concat3 ======================== volname: vol/vol3 subvolume: subvol/vol3/data size: 11110890 iou: 1 pieces: 5 open: no state: 0xa (valid,online) user-flags: online,autoname uuid: 39798cff-9c4f-1022-8544-0800690565c0 tid: 926520978 (05/12/99_09:56:18) Type-specific information: --------------------------- (n/a) Local stats for concat/concat3 since being enabled or reset: ---------------------------------------------------------------------- read requests: 10 write requests: 40 512 byte blks read: 640 512 byte blks written: 14080 reads straddling slices: 0 writes straddling slices: 0 Pieces: # Size Timestamp Type/Name State ----------------------------------------------------------- 0 2222178 05/12/99_06:48:56 slice/maules0 valid,online 1 2222178 05/12/99_06:48:56 slice/maules1 valid,online 2 2222178 05/12/99_06:51:01 concat/concat0 valid,online 3 2222178 05/12/99_06:48:56 slice/maules3 valid,online 4 2222178 05/12/99_06:48:56 slice/maules4 valid,online |
In addition to the read and write requests for the mirror, mirror statistics show the mirror synchronization reads and writes.
The following example displays the results of a show command on a mirror for which statistics have been turned on:
xvm:cluster> show -v mirror/mirror0 XVM ve mirror/mirror0 ======================== volname: vol/vol3 subvolume: subvol/vol3/data size: 11110890 iou: 1 pieces: 1 open: no state: 0xa (valid,online) user-flags: online,autoname uuid: 39798d05-9c4f-1022-8544-0800690565c0 tid: 926509854 (05/12/99_06:50:54) Type-specific information: --------------------------- rpolicy: 0 (round-robin) config: 0x0 (none) drl flush frequency (sec): (n/a) primary piece: 0 reviving: no Local stats for mirror/mirror0 since being enabled or reset: ---------------------------------------------------------------------- read requests: 10 write requests: 40 512 byte blks read: 640 512 byte blks written: 14080 Mirror synchronization reads: 0 Mirror synchronization writes: 0 Leg Reads Writes 0 10 40 Pieces: # Size Timestamp Type/Name State ----------------------------------------------------------- 0 11110890 05/12/99_09:56:18 concat/concat3 valid,online |
Slice statistics show the number of read and write operations as well as the number of 512K blocks read and written.
The following example displays the results of a show command on a slice for which statistics have been turned on:
xvm:cluster> show -v slice/cxfsdsk1s0 XVM ve slice/cxfsdsk1s0 ======================== volname: vol/cxfsvol subvolume: subvol/cxfsvol/data size: 17779016 iou: 1 pieces: 0 open: no state: 0xa (valid,online) user-flags: online,autoname uuid: 31350c53-7aa4-1022-85f1-0800690592c9 tid: 922806049 (03/30/99_09:00:49) Type-specific information: --------------------------- physvol: cxfsdsk1 start: 0 length: 17779016 Local stats for slice/cxfsdsk1s0 since being enabled or reset: ---------------------------------------------------------------------- read requests: 956 write requests: 0 512 byte blks read: 7684 512 byte blks written: 0 Pieces: # Size Timestamp Type/Name State ----------------------------------------------------------- (Ve has no pieces) |