volstat(8)volstat(8)NAMEvolstat - Logical Storage Manager statistics management utility
SYNOPSIS
/usr/sbin/volstat [-g diskgroup] [-i interval] [-c count] [-f format]
[-r] [-psvd] [object...]
OPTIONS
The following options are recognized: Selects records from the speci‐
fied 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 specified 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 for‐
mats are available: 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 inter‐
val. These statistics are displayed as the default output format.
Displays statistics on atomic copies performed (has meaning only for
mirrored volumes) using the following fields: number of operations,
number of blocks, and the average time spent per operation. Displays
statistics on verified reads and writes (has meaning only for mirrored
volumes) using the following fields: number of verified read opera‐
tions, number of verified write operations, number of blocks read, num‐
ber of blocks written, average time spent on verified read operations
in the interval, and average time spent on verified write operations in
the interval. Displays the number of corrected (fixed) read and write
operations (has meaning only for mirrored or RAID5 volumes).
Note
Currently, only read operations are corrected, so the number of
fixed writes will always be zero. Displays the number of failed
read and write operations. 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 opera‐
tions to a mirrored volume invoke read-writeback consistency
recovery. 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 optimization. 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 rep‐
resents 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. Dis‐
plays 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 repre‐
sents only the size of the requested write. The read portion of
the I/O can be derived. Displays reconstruct write statistics.
Each operation counted is for a reconstruct write operation per‐
formed 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 read operations. Displays
reconstruct read operations. Each operation is a separate recon‐
struct read operation. A single stripe read or write operation
can lead to numerous reconstruct read operations since each
reconstruction takes place at the subdisk level. A detached col‐
umn can consist of several subdisks, each leading to a recon‐
struct read operation. 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 operation. 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. Displays statis‐
tics for the VOL_R5_RECOVER operation. Each operation count rep‐
resents one call to the VOL_R5_RECOVER ioctl. The number of
blocks represents the resulting number of blocks that were writ‐
ten to the missing column region as part of the data recovery.
The read operations are not counted towards the total. 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. Resets
statistics instead of printing them. This option follows the
same selection rules as printing for any type selection argu‐
ments 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. 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 disk. 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.
Displays statistics for subdisks on the objects specified on the
command line. Displays statistics for disks on which the object
specified on the command line is fully or partially located.
DESCRIPTION
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 specified disk group are reported. If no disk group is specified,
the rootdg disk group is implied.
Note
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.
OUTPUT FORMAT
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 line.
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 ses‐
sion 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
EXIT CODES
The volstat utility exits with a nonzero status if the attempted opera‐
tion fails. A nonzero exit code is not a complete indicator of the
problems encountered, but rather denotes the first condition that pre‐
vented further execution of the utility. See volintro(8) for a list of
standard exit codes.
EXAMPLES
To display statistics for LSM volumes in the rootdg disk group, enter:
# volstat-v To display statistics for LSM volumes in a disk group
called dg1, enter: # volstat-g dg1 -v To display statistics for the
plexes and subdisks of a volume named blop, enter: # volstat-ps blop
To reset all statistics for a disk group named foodg, enter: # volstat-g foodg -r To display 5 sets of disk statistics at 10 second inter‐
vals, enter: # volstat-i 10 -c 5 -d
SEE ALSO
Commands: volintro(8), voltrace(8)volstat(8)
