Hi Brock,

On Monday 04 February 2008 07:11:11 am Brock Palen wrote:
on our cluster that has been running lustre for about 1 month. I have
1 MDT/MGS and 1 OSS with 2 OST's.

Our cluster uses all Gige and has about 608 nodes 1854 cores.

This seems to be a lot of clients for only one OSS (and thus for only
one GigE link to the OSS).

Its more for evaluation, the 'real' file system is a NFS file system provided by a OnStor bobcat. So anything is a improvement. The cluster IS to big, but there isn't a person at the university who is willing to pay for anything other than more cluster nodes. Enough with politics.


We have allot of jobs that die, and/or go into high IO wait,  strace
shows processes stuck in fstat().

The big problem is (i think) I would like some feedback on it that of
these 608 nodes 209 of them have in dmesg the string

"This client was evicted by"

Is this normal for clients to be dropped like this?

I'm not an expert here, but evictions typically occur when a client
hasn't been seen for a certain period by the OSS/MDS. This is often
related to network problems. Considering your number of clients, if
they all do I/O operations on the filesystem concurrently, maybe your
Ethernet switches are the bottleneck and have to drop packets. Is your
GigE network working fine outside of Lustre?

To eliminate networking issues from the equation, you can try to lctl
ping your MDS and OSS from a freshly evicted node, and see what you
get. (lctl ping <your-oss-nid>)

I just had another node get evicted while running code causing the code to lock up. This time it was the MDS that evicted it. Pinging work though:

[EMAIL PROTECTED] ~]# lctl ping [EMAIL PROTECTED]
[EMAIL PROTECTED]
[EMAIL PROTECTED]

Recovery is slow, this clinet has been evicted for about 10 minutes.

I have attached the output of lctl dk from the client and some syslog messages from the MDS.


Is there some
tuning that needs to be done to the server to carry this many nodes
out of the box?  We are using default lustre install with Gige.

Do your MDS or OSS show any particularly high load or memory usage? Do
you see any Lustre-related error messages in their logs?

Nope both servers have 2GB ram, and load is almost 0.  No swapping.
Thanks

Attachment: client.err
Description: Binary data

Attachment: mds.log
Description: Binary data





CHeers,
--
Kilian



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