Having followed the http://wiki.freebsd.org/ZFSTuningGuide, when configuring ZFS, I was aware of the delicate nature of the kernel settings for ZFS on i386. I recently upgraded my server to 4GB ECC from 2GB non-ECC and thought I’d like to take advantage of the extra ram, so I thought I’d play around with these options.
My current kernel config could not be simpler, ZFS-GENERIC:
include GENERIC
ident ZFS-GENERIC
options KVA_PAGES=512
For this configuration I successfully used in /boot/loader.conf:
#Working options for ZFS-GENERIC 2GB RAM, KVA_PAGES=512
vm.kmem_size=”1536M”
vm.kmem_size_max=”1536M”
vfs.zfs.arc_max=”786M”
I thought it would be as simple as:
#Trial options for ZFS-GENERIC 4GB RAM, KVA_PAGES=512
vm.kmem_size=”2G”
vm.kmem_size_max=”2G”
vfs.zfs.arc_max=”1792M”
But, but to my chagrin, my system responded on boot up with a:
panic: kmem_suballoc: bad status return of 3
Continue reading Tweaking ZFS on FreeBSD 8.2-RELEASE on i386