If you're not already familiar with it, I find the following command useful. It
shows the realtime total read commands, number hitting/missing ARC, number
hitting missing L2ARC, breakdown of MRU/MFU etc.

arcstat_v2.pl -f
read,hits,mru,mfu,miss,hit%,l2read,l2hits,l2miss,l2hit%,arcsz,l2size,mrug,mfug 1

That version of Arcstat is from http://github.com/mharsch/arcstat

For comparison, I've got about 650GB of VMs on each of my two Nexenta VSAs
(16GB/240GB L2ARC).   When it's just ticking over at 50-1000r/s then 99% of that
is going to ARC but I'm also seeing patches where it goes 2-5k reads and I'm
seeing 20-80% l2arc hits.  These have been running for about a week and, given
my understanding of how L2ARC fills, I'd suggest maybe leaving it to warm up
longer (e.g. 1-2 weeks?)

caveat: I'm a complete newbie to zfs so I could be completely wrong ;)


zfs-discuss mailing list

Reply via email to