zfs snapdir NFS hang

[Peter Maloney]

On 02/09/2012 04:42 PM, Peter Maloney wrote:
> ...
> And for the record, I have tested full scans of the .zfs/snapshot
> directory using "find" to see if it "brings the server to its knees" as
> is often said, but even that does not cause any problems at all (with 48
> GB of memory on this machine). I am currently running another run of
> that test, and will tell you the result in 20 or so hours when it is done.
>
> # time find /tank/bcnasvm1/.zfs/snapshot -type f > /dev/null 2>&1
The result was that the system seemed fine, for a while, but after
fiddling with NFS and snapshots, eventually every new process (eg. a
local login on the machine terminals) would be killed with a message
about being out of swap space. I guess it can only eat all your memory
when you have more data or snapshots, because fun stuff like this didn't
happen before. Or perhaps I didn't catch it before, because I didn't try
fiddling with other things the last time I tested it.