[gpfsug-discuss] Looking for a way to see which node is having an impact on server?

[Richard Lefebvre]

Hi,

I'm looking for a way to see which node (or nodes) is having an impact
on the gpfs server nodes which is slowing the whole file system? What
happens, usually, is a user is doing some I/O that doesn't fit the
configuration of the gpfs file system and the way it was explain on how
to use it efficiently.  It is usually by doing a lot of unbuffered byte
size, very random I/O on the file system that was made for large files
and large block size.

My problem is finding out who is doing that. I haven't found a way to
pinpoint the node or nodes that could be the source of the problem, with
over 600 client nodes.

I tried to use "mmlsnodes -N waiters -L" but there is too much waiting
that I cannot pinpoint on something.

I must be missing something simple. Anyone got any help?

Note: there is another thing I'm trying to pinpoint. A temporary
imbalance was created by adding a new NSD. It seems that a group of
files have been created on that same NSD and a user keeps hitting that
NSD causing a high load.  I'm trying to pinpoint the origin of that too.
At least until everything is balance back. But will balancing spread
those files since they are already on the most empty NSD?

Richard