ZFS memory exhaustion?

[Freddie Cash]

On Tue, Jul 16, 2013 at 1:26 PM, javocado <javocado at gmail.com> wrote:

> I have a couple questions:
>
> - what does it look like when zfs needs more physical memory / is running
> out of memory for its operations?
>

Disk I/O drops to 0, reading/writing any file from the pool appears to
"hang" the console, programs already loaded into RAM continue to work so
long as they don't touch the pool, etc.


>
> - what diagnostic numbers (vmstat, etc.) should I watch for that?
>
> Top output will show Wired at/near 100% of RAM.


> swapinfo shows zero (basically zero) swap usage, so it doesn't look like
> things get that bad.
>
>
ZFS uses non-swappable kernel memory, so you won't ever see swap used when
ZFS runs out of RAM.

Those are the symptoms we've noticed when our ZFS systems have run out of
RAM.


-- 
Freddie Cash
fjwcash at gmail.com