[PATCH] Simple ARC stats in top

[Mark Felder]

On Tue, 26 Jun 2012 10:55:12 -0500, Andriy Gapon <avg at freebsd.org> wrote:

> Does your system also has L2 ARC?
> If so, could you please show a value of  
> kstat.zfs.misc.arcstats.l2_hdr_size?
> Otherwise, it's hard for me to explain the huge difference between Max  
> Size and
> ARC Size.

Yes, it does.

zfs2# sysctl kstat.zfs.misc.arcstats.l2_hdr_size
kstat.zfs.misc.arcstats.l2_hdr_size: 6775072568

zfs2# zfs-stats -L

------------------------------------------------------------------------
ZFS Subsystem Report				Tue Jun 26 10:56:54 2012
------------------------------------------------------------------------

L2 ARC Summary: (HEALTHY)
	Passed Headroom:			61
	Tried Lock Failures:			252.97k
	IO In Progress:				0
	Low Memory Aborts:			0
	Free on Write:				382.20k
	Writes While Full:			11.08k
	R/W Clashes:				270
	Bad Checksums:				0
	IO Errors:				0
	SPA Mismatch:				0

L2 ARC Size: (Adaptive)				225.09	GiB
	Header Size:			2.80%	6.31	GiB

L2 ARC Breakdown:				25.52m
	Hit Ratio:			87.46%	22.32m
	Miss Ratio:			12.54%	3.20m
	Feeds:					3.99m

L2 ARC Buffer:
	Bytes Scanned:				42.67	TiB
	Buffer Iterations:			3.99m
	List Iterations:			255.38m
	NULL List Iterations:			219.99m

L2 ARC Writes:
	Writes Sent:			100.00%	913.05k

------------------------------------------------------------------------