Re: new ZFS sysctls not working?

On Mon, Apr 09, 2007 at 10:07:12PM -0500, Doug Poland wrote:
On Mon, Apr 09, 2007 at 10:58:55PM -0400, Kris Kennaway wrote:
On Mon, Apr 09, 2007 at 09:50:20PM -0500, Doug Poland wrote:
On Mon, Apr 09, 2007 at 09:05:32PM -0400, Kris Kennaway wrote:
On Mon, Apr 09, 2007 at 06:26:54PM -0500, Doug Poland wrote:
Hello,

It would appear that the new sysctls for ZFS
(vfs.zfs.arc_max/min) are not "taking". i.e.,

# cat /boot/loader.conf
vfs.zfs.arc_max=134217728
vfs.zfs.arc_min=134217728

# sysctl -a | grep vfs.zfs.arc
vfs.zfs.arc_max: 67108864
vfs.zfs.arc_min: 67108864

This is after a fresh cvsup run today around 10:00 CDT.

Please provide more details of your system, e.g. sysctl
vm.kmem_size.

FreeBSD 7.0-CURRENT #0: Mon Apr 9 12:55:54 CDT 2007
djp@xxxxxxxxxxxxxxxx:/usr/obj/usr/src/sys/GENERIC
WARNING: WITNESS option enabled, expect reduced performance.
Timecounter "i8254" frequency 1193182 Hz quality 0
CPU: AMD Athlon(tm) processor (1403.19-MHz 686-class CPU)
Origin = "AuthenticAMD" Id = 0x644 Stepping = 4
Features=0x183f9ff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,MMX,FXSR>
AMD Features=0xc0440800<SYSCALL,<b18>,MMX+,3DNow!+,3DNow!>
real memory = 259981312 (247 MB)
avail memory = 240451584 (229 MB)

# sysctl -a | grep vm.kmem_size
vm.kmem_size: 80662528
vm.kmem_size_max: 335544320
vm.kmem_size_scale: 3

Yeah, you don't even have 128 MB of kmem available (only 76 MB), so
it's no surprise zfs refused to use that much ;-)

I was attempting to "portsnap extract" to a two disk ZFS mirror. It
would appear my ability to test ZFS is severly limited on this
particular hardware configuration. Sorry for the noise...

Well you can increase your kmem a bit, but yeah, it's probably not
going to perform very well because you're taking it away from userland
so there will be increased swap activity too.

Kris

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