volstat - Logical Storage Manager statistics management
utility
/usr/sbin/volstat [-g diskgroup] [-i interval] [-c count]
[-f format] [-r] [-psvd] [object...]
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 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 formats 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 interval.
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 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. 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 operations
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 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. 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 derived. 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 read
operations. 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 reconstruction takes place at the subdisk
level. A detached column can consist of several
subdisks, each leading to a reconstruct 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 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. 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 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. 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.
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.
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 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 codes.
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 intervals, enter: # volstat -i 10 -c 5 -d
Commands: volintro(8), voltrace(8)
volstat(8)
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