Problems with many open files using Arla and Mosix

[Magnus Ahltorp]

> we are trying to run Mosix together with AFS. This works mostly
> fine, except when stressing the AFS server by working on lots of
> files shortly after another, like when untarring a linux kernel in
> AFS filespace. The server uses a lot of file handles (about 9500),
> and it seems that Mosix somehow breaks at that amount of open files.
> Suddently the AFS clients cannot allocate any more memory, even
> though 'free' shows lots of free space.

Excuse me for not knowing anything about Mosix, but where are you
running it? On the server or on the clients, or both? The "AFS
clients" that you say cannot allocate more memory, is that Arla, or do
you mean tar? What error message do you get?

Do you mean that the client opens that many files? tar shouldn't open
lots of files, just one at a time (except for directories).

> Is there a fixed limit on the number of open files, or does anyone
> have an idea as to why this happens?

There is a limit of the number of open files on a machine in linux.
You can see that in /proc/sys/fs/file-max. It seems to be 8192 by
default.

> We are running mosix1.0.3 on linux2.4.5, openafs1.0.4 server and
> arla0.35.4 client. MFS and DFSA are disabled.
> 
> The same setup, except without mosix compiled in, works fine.

What does "compiled in" mean here? Is it a kernel module, or a kernel
patch?

/Magnus