volstat - Logical Storage Manager statistics management utility
/usr/sbin/volstat [-g diskgroup] [-i interval] [-c count] [-f format] [-r]
The following options are recognized:
Selects records from the specified disk group. The diskgroup option
argument can be either a disk group name or disk group ID. If no disk
group is specified then the rootdg disk group is assumed unless speci-
fied objects cannot be found in rootdg but can be found uniquely in
another disk group.
Prints the change in volume statistics that occurs after every interval
seconds. The first interval is assumed to encompass the entire previous
history of objects. Subsequent displays will show statistics with a
zero value if there has been no change since the previous interval.
Stops after printing interval statistics count times.
Specifies the output format for the collected statistics. The default
is -f s. The following formats are available:
s Displays statistics on read and write operations. The output is
formatted into six fields: the number of read operations, the
number of write operations, the number of blocks read, the number
of blocks written, the average time spent on read operations in the
interval, and the average time spent on write operations in the
interval. These statistics are displayed as the default output
a Displays statistics on atomic copies performed (has meaning only
for mirrored volumes) using the following fields: number of opera-
tions, number of blocks, and the average time spent per operation.
v Displays statistics on verified reads and writes (has meaning only
for mirrored volumes) using the following fields: number of veri-
fied read operations, number of verified write operations, number
of blocks read, number of blocks written, average time spent on
verified read operations in the interval, and average time spent on
verified write operations in the interval.
c Displays the number of corrected (fixed) read and write operations
(has meaning only for mirrored or RAID5 volumes).
Currently, only read operations are corrected, so the number of
fixed writes will always be zero.
f Displays the number of failed read and write operations.
b Displays the statistics on read-writeback mirror consistency
recovery operations (has meaning only for mirrored volumes) using
the following fields: number of read-writeback operations, number
of blocks involved in read-writeback operations, and average time
for completing a read-writeback operation. While in recovery mode,
most read operations to a mirrored volume invoke read-writeback
F Displays statistics for full-stripe writes on a RAID5 volume. The
number of operations represents the number of write operations
within a stripe that were conducted as a full-stripe write optimi-
zation. Full-stripe writes represent considerably less overhead
than read-modify-writes in terms of overall I/O time, latency and
CPU overhead. The total number of blocks represents the total size
of the written data and the average time is the time taken for a
full-stripe write operation. Since the I/O may be larger than a
single stripe, more than one stripe operation may be seen for a
single logical I/O request.
M Displays read-modify-write statistics. Each operation represents a
read-modify write operation performed within a stripe. I/O crossing
a stripe boundary is represented by more than a single read-modify
write operation. The number of blocks counted represents only the
size of the requested write. The read portion of the I/O can be
W Displays reconstruct write statistics. Each operation counted is
for a reconstruct write operation performed as an optimization of a
write operation within a stripe. The number of blocks counted
represents the count of data blocks written not including parity or
R Displays reconstruct read operations. Each operation is a separate
reconstruct read operation. A single stripe read or write operation
can lead to numerous reconstruct read operations since each recon-
struction takes place at the subdisk level. A detached column can
consist of several subdisks, each leading to a reconstruct read
0 Displays statistics for the VOL_R5_ZERO operation. Each operation
represents one call to the VOL_R5_ZERO ioctl. The number of blocks
is based on the number of zero'd blocks written to the array. The
average time is the time taken to complete the entire ioctl opera-
S Displays statistics for the VOL_R5_RESYNC operation. Each operation
count represents one call to the VOL_R5_RESYNC ioctl. The number of
blocks represents the resulting number of blocks that were written
to the parity regions as part of the resynchronization of parity.
The read operations are not counted towards the total.
C Displays statistics for the VOL_R5_RECOVER operation. Each
operation count represents one call to the VOL_R5_RECOVER ioctl.
The number of blocks represents the resulting number of blocks that
were written to the missing column region as part of the data
recovery. The read operations are not counted towards the total.
V Displays statistics for the VOL_R5_VERIFY operation. Each operation
count represents one call to the VOL_R5_VERIFY ioctl. The number of
blocks represents the resulting number of blocks that were read as
part of the RAID5 stripes consistency verification.
-r Resets statistics instead of printing them. This option follows the
same selection rules as printing for any type selection arguments or
for any named objects. If an interval was specified on the command
line, the first set of statistics will not be printed since they will
have been reset to zero. Subsequent activity will cause printing of
statistics as normal.
-v Displays statistics for volumes on the objects specified on the command
line. If an object is a plex or a subdisk, displays information about
the volume with which the object is associated. If an object is a
disk, displays information for any volumes that occupy any part of the
-p Displays statistics for plexes on the object specified on the command
line. For subdisk objects, displays information about a plex with which
it is associated.
-s Displays statistics for subdisks on the objects specified on the com-
-d Displays statistics for disks on which the object specified on the com-
mand line is fully or partially located.
The volstat utility prints and resets statistics information on one or more
volumes, plexes, subdisks, or disks.
The volstat utility reads statistics from the /dev/volinfo device to report
performance statistics for volume, plex, subdisk, and disk media objects.
The statistics are since the last reboot, the last time they were reset, or
for the interval specified.
The object parameter can be the name of a volume, plex, subdisk, or disk.
If no object operands are given, statistics from all volumes in the speci-
fied disk group are reported. If no disk group is specified, the rootdg
disk group is implied.
In TruCluster environments, the volstat command only reports statistic
information for that node. It does not provide aggregate statistic
information for the whole TruCluster environment.
Summary statistics for each object are printed in one-line output records,
preceded by two header lines. The output line consists of blank-separated
fields for the object type, object name (standard), and the fields
requested by the -f switch in the order they are specified on the command
If the -i interval option was specified, statistics are prefaced with a
time-stamp showing the current local time on the system.
For example, here is a sample of the output for a typical volstat session
using the default format:
# volstat -vpsd -g data_g01 -i 10 -c 3
OPERATIONS BLOCKS AVG TIME(ms)
TYP NAME READ WRITE READ WRITE READ WRITE
Aug 22 12:25:23 1997
dm dsk135 119 210 2944 3392 18.9 2.8
dm dsk125 118 212 2928 3424 23.3 22.0
vol vol01 237 212 5872 3424 21.1 22.0
pl pl-01 118 212 2928 3424 23.3 22.0
sd dsk125-01 118 212 2928 3424 23.3 22.0
pl pl-02 119 210 2944 3392 18.9 2.8
sd dsk135-01 119 210 2944 3392 18.9 2.8
The volstat utility exits with a nonzero status if the attempted operation
fails. A nonzero exit code is not a complete indicator of the problems
encountered, but rather denotes the first condition that prevented further
execution of the utility. See volintro(8) for a list of standard exit
1. To display statistics for LSM volumes in the rootdg disk group, enter:
# volstat -v
2. To display statistics for LSM volumes in a disk group called dg1,
# volstat -g dg1 -v
3. To display statistics for the plexes and subdisks of a volume named
# volstat -ps blop
4. To reset all statistics for a disk group named foodg, enter:
# volstat -g foodg -r
5. To display 5 sets of disk statistics at 10 second intervals, enter:
# volstat -i 10 -c 5 -d
Commands: volintro(8), voltrace(8)