zfs arc eating up all memory

[Claudius Herder]

On 23/01/12 21:46, Peter Maloney wrote:

> Dunno, but I make it a policy to always hide it. You can still type in
> the .zfs directory and it uses it even if hidden.
> 
> Try it.
> 
> zfs set snapdir=hidden mypool/home/claudius
> cd ~claudius/.zfs/snapshot
> ls
> 
yes I know and I think it is a really nice feature for users to be able
to restore files by themselves.

> The reason I decided to do that, is because I found that when an NFS
> client does an ls inside the .zfs/snapshot directory, it hangs the server ;)

at my server `ls .zfs/snapshot/` works, but `ls -R .zfs/snapshot/` kills
the server. Same for `find .zfs/snapshot -name foo`.

> But the client can still do the same, just manually typing the
> directory... so I also mounted /var/empty on top of it to hide it on the
> client. (and my users use the client system through samba, not the zfs
> system with NFS)

I'm not very fond of this idea, but for the moment it will prevent
server crashes, which is fine. Thanks for the hint.

I did some further testing:
My i368 vm is able to search 100 snapshots with 8601040 files without
problems with 1gb ram und 1 gb swap.

My amd64 server is not able to search 4280597 files with 8gb ram and 4gb
swap.

At the last halt arc consumed only 5,5gb memory and as I understand arc
would not steal memory from other processes, is this assumption correct?

Maybe this problem is totally unrelated to arc and there is something
else claiming all memory?

How can I investigate this issue further?

--
Claudius