Filesystem latencies with fsstat.

After my blog entry about showing latencies at disk level, I want to highlight another tool that is now able to display latencies, just somewhat up the layers (or layer, given a blatant layering violation is in place ;-) ). The fsstat command got a -l option. With this tool you can check latencies from the perspective of the filesystem. It does so for read, write and readdir operations. It’s really simple to use:

root@solaris1144:~# fsstat -l / 1
 read read   read write write write rddir rddir rddir
  ops bytes  time   ops bytes  time   ops bytes  time
 135K  502M    <strong>4n</strong> 13,8K  194M    <strong>0n</strong> 10,9K 3,72M <strong>45,0n</strong> /
   20 3,83K 35,0n     0     0    0n     0     0    0n /
    0     0    0n     0     0    0n     0     0    0n /

I don’t use fsstat as frequent as iostat, nevertheless a really useful addition from my perspective.