vm.kmem_size settings doesn't affect loader?
koitsu at FreeBSD.org
Thu Sep 25 13:02:29 UTC 2008
On Thu, Sep 25, 2008 at 12:26:58PM +0200, Bartosz Stec wrote:
> Today I've experienced zfs-related kernel panic. Log says:
> savecore: reboot after panic: kmem_malloc(131072): kmem_map too
> small: 327684096 total allocated
> Reported amount of memory (327684096) is wrong, because i made suggested
> tuning in my loader.conf:
> Just to be sure:
> # sysctl vm | grep kmem
> vm.kmem_size: 536870912
> vm.kmem_size_min: 0
> vm.kmem_size_max: 536870912
> vm.kmem_size_scale: 3
> Am I missing something?
I believe this is normal. The amount shown in "total allocated" will
not match what you have vm.kmem_size or vm.kmem_size_max set to.
Someone more familiar with the VM can explain why this is, but as I
understand it, it's 100% normal.
Your options are:
1) Consider increasing it from 512M to something like 1.5GB; do not
increase it past that on RELENG_7, as there isn't support for more than
2GB total. For example, on a 1GB memory machine, I often recommend
768M. On 2GB machines, 1536M. You will need to run -CURRENT if you
2) Tune ZFS aggressively. Start by setting vfs.zfs.arc_min="16M"
If your machine has some small amount of memory (768MB, 1GB, etc.),
then you probably shouldn't be using ZFS.
| Jeremy Chadwick jdc at parodius.com |
| Parodius Networking http://www.parodius.com/ |
| UNIX Systems Administrator Mountain View, CA, USA |
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