Re: ZFS committed to the FreeBSD base.

On Tue, Apr 10, 2007 at 04:38:57AM +0200, Pawel Jakub Dawidek wrote:
> ARC and ZIO are the biggest memory consumers and they are somehow
> connected. I just committed changes that should stabilize ZFS in this
> regard. Could you try them?

Preliminary results with the latest -current kernel and
vm.kmem_size=268435456, disabling all my other loader.conf entries and
letting it autosize:

kstat.zfs.misc.arcstats.p: 15800320
kstat.zfs.misc.arcstats.c: 16777216
kstat.zfs.misc.arcstats.c_min: 16777216
kstat.zfs.misc.arcstats.c_max: 134217728
kstat.zfs.misc.arcstats.size: 18003456

solaris 43705 91788K       -  4522887      16,32,64,128,256,512,1024,2048,4096

So it looks like it autosized the ARC to a 16M-128M range.  I'm
currently doing a buildworld and am going to try untarring the ports
tree.  The ARC size is tending to hover around 16-20M, probably due to
memory pressure.  The "solaris" group appears to be taking up about 16M
less memory than it did before, which is consistent with the ARC being
16M smaller (I had changed the minimum to 32M before reverting to HEAD).

I may poke around in ZIO but judging from the complexity of the code I
don't have much of a chance of really understanding it anytime soon.

In my defense, the machine I was planning to use this on isn't _that_
old.  It's a 2Ghz P4, which should be "okay" as far as checksum
calculations go.  It just has a braindead motherboard that refuses to
accept more than 512MB of RAM.

Craig