[Lustre-discuss] Aborting recovery

[Thomas Roth]

Thanks Brian.

Brian J. Murrell wrote:
> On Thu, 2009-03-05 at 22:19 +0100, Thomas Roth wrote:
>> My question: what happens to the one client that was not recovered?
> 
> It, and all of the clients that have transactions that need to be
> replayed after the AWOL client's transactions are all evicted and their
> transactions discarded.
> 
>> There can be no real damage to the client or the jobs that were
>> running on it, all dead anyhow since Lustre was gone for such a long time.
> 
> Clients configured for failover will wait indefinitely for a Lustre
> server to return to service so there is no concept of "such a long
> time".

What I meant: the average batch job that wants to read from or write to
Lustre will abort if a file cannot be accessed. The reason doesn't
matter to the jobs or the user.
So the Lustre client may wait forever, but for the users that is
irrelevant, they have to resubmit their jobs in any case.

I was wondering whether a client whose transactions have not been
replayed may get into some zombie state. Of course I see in the logs of
MDS and clients what is supposed to happen, that remainig stuff on the
client is discarded, inodes deleted etc. In some cases this will not
work, I'm sure. But then reboot of the client will clean up.

Regards,
Thomas


>> What are the effects on the client side?
>> Maybe I have to remount Lustre on that machine?
> 
> An evicted client will reconnect without need for unmounting etc.
> However that it was evicted, any applications that were processing
> Lustre I/O will get an EIO.
> 
> b.
> 
> 
> 
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Thomas Roth
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