ZFS Tuning - arc_summary.pl
ben at wanderview.com
Mon Mar 29 16:28:05 UTC 2010
On Mar 29, 2010, at 10:43 AM, Barry Pederson wrote:
> I've been using the arc_summary.pl script from here:
> and noticed some odd numbers, with the ARC Current Size being larger than the Max Size, and the breakdown adding up to less than the current size as shown below
I believe the current size can be larger than the max if your working data set is large enough. The ARC can't evict data that is still being referenced. When I last looked (over a year ago) there was no mechanism to provide back pressure from the ARC to the VM layer to request that more nodes be released to help deal with this situation.
I don't know if that really helps at all, but I just thought I would add the data point from my previous debugging sessions with zfs.
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