zfsonlinux/zfs — pull request #786 by dechamps (2012-06-15 14:46:38+00:00)
Title: Add ZIL statistics

The performance of the ZIL is usually the main bottleneck when dealing with synchronous, write-heavy workloads (e.g. databases). Understanding the behavior of the ZIL is required to diagnose performance issues for these workloads, and to tune ZIL parameters (like `zil_slog_limit`) accordingly.

This commit adds a new kstat page dedicated to the ZIL with some counters which, hopefully, scheds some light into what the ZIL is doing, and how it is doing it.

Currently, these statistics are available in `/proc/spl/kstat/zfs/zil`. A description of the fields can be found in zil.h.