All the memory eaten away by ZFS 'solaris' malloc - on 11.1-R amd64

Shane Ambler FreeBSD at ShaneWare.Biz
Wed Aug 1 01:35:11 UTC 2018

On 01/08/2018 07:24, Mark Martinec wrote:
> I have now upgraded this host from 11.1-RELEASE-p11 to 11.2-RELEASE
> and the situation has not improved. Also turned off all services.
> ZFS is still leaking memory about 30 MB per hour, until the host
> runs out of memory and swap space and crashes, unless I reboot it
> first every four days.
> Any advise before I try to get rid of that faulted disk with a pool
> (or downgrade to 10.3, which was stable) ?
>   Mark
> 2018-07-23 17:12, myself wrote:
>> After upgrading an older AMD host from FreeBSD 10.3 to 11.1-RELEASE-p11
>> (amd64), ZFS is gradually eating up all memory, so that it crashes every
>> few days when the memory is completely exhausted (after swapping heavily
>> for a couple of hours).
>> This machine has only 4 GB of memory. After capping up the ZFS ARC
>> to 1.8 GB the machine can now stay up a bit longer, but in four days
>> all the memory is used up. The machine is lightly loaded, it runs
>> a bind resolver and a lightly used web server, the ps output
>> does not show any excessive memory use by any process.

When you say all used up - you mean the amount of wired ram goes higher
than about 90% physical ram? You can watch the wired amount in top, or
calculate it as vm.stats.vm.v_wire_count * hw.pagesize

ZFS ARC is marked as wired, there is also vm.max_wired which limits how
much the kernel can wire, this defaults to 30% ram, so about 1.2G for
you. It seems these two wired values don't interact and can add up to
more than physical ram. I have reported this in bug 229764

Try the patch at
it has given me the best arc related memory improvements I have seen
since 10.1, I now see arc being released instead of swap being used.

FreeBSD - the place to B...Software Developing

Shane Ambler

More information about the freebsd-stable mailing list