Monitoring File System Latency with fsstat

Solaris 11.4 (beta) comes with a new version of the fsstat command. Why is this interesting? Because with the newly added -l option now fsstat is able to repot latency information on read, write, and readdir operations for file system types or individual file systems.
The latency information is independent of physical I/O operations
Therefore it is representative of file system performance, as seen by applications which helps improving troubleshooting performance issues in that area.

One small step for fsstat, one giant leap for troubleshooting enhancement and user experience.

Here is a quick example:

root@wacken:~# fsstat zfs proc tmpfs 1
 new  name   name  attr  attr lookup rddir  read read  write write
 file remov  chng   get   set    ops   ops   ops bytes   ops bytes
71.0K 44.7K 7.51K 1.42M 1.22K  6.93M 26.8K  240K 1019M  111K 3.61G zfs
    0     0     0 8.95K     0  19.8K 63.0K 3.01K 6.05M     9   584 proc
6.96K   646   315  152K 24.4K  82.5K    70 45.4K 83.1M  205K 3.00G tmpfs
    0     0     0 13.3K     0  33.2K   126    14 2.83K     0     0 zfs
    0     0     0 6.26K     0  14.4K   303    40 17.2K     0     0 proc
    0     0     0   377     0     45     0     0     0     0     0 tmpfs
    0     0     0     0     0      1     0     0     0     0     0 zfs
    0     0     0     2     0      2     2     1   440     0     0 proc
    0     0     0     0     0      0     0     0     0     0     0 tmpfs
^C
root@wacken:~# fsstat -l zfs proc tmpfs 1
 read read   read write write write rddir rddir rddir
  ops bytes  time   ops bytes  time   ops bytes  time
 241K 1019M    4n  111K 3.61G 3.00n 30.4K 10.6M  194n zfs
3.06K 6.07M 3.00n     9   584  261n 63.3K 67.9M  232n proc
45.5K 83.1M  295n  206K 3.01G    0n    70 3.58K 45.0n tmpfs
   14 2.83K 48.0n     0     0    0n     0     0    0n zfs
    0     0    0n     0     0    0n     2 2.27K  168n proc
    0     0    0n     0     0    0n     0     0    0n tmpfs
    0     0    0n     0     0    0n     0     0    0n zfs
    1   440 37.0n     0     0    0n     2 2.30K  218n proc
    0     0    0n     0     0    0n     0     0    0n tmpfs
    0     0    0n     0     0    0n   980  193K  100n zfs
    0     0    0n     0     0    0n    41 10.4K  149n proc
    0     0    0n     0     0    0n     0     0    0n tmpfs
^C

This will be pretty useful from time to time.

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