NFS consistency problem?

[Trond Myklebust]

On Mon, 2007-05-07 at 20:00 +0200, Jonathan Schmitt wrote:
> Hi Trond,
> 
> Am Montag, 7. Mai 2007 17:08 schrieb Trond Myklebust:
> > What about the results of 'stat file.txt'? Do they match on clients A
> > and B, or do they differ? If so, how do they differ?
> 
> I just tried again. This time, I found 2 Bs amongst 8 As, so not all write 
> access from one machine got lost this time (still 3/4).
> 
> stat gives identical output on both pcs if both try writing. If only A tries 
> writing, I could see that the file was not updated on B for a small amount of 
> time (maybe the already discussed second). However I already had a situation 
> where this update was not done for several minutes - but this seems harder to 
> reproduce.

If you could reproduce it together with a binary tcpdump (use 'tcpdump
-s 9000 -w /tmp/dump.dmp' from the server).

> So, if you all allow, I would like to summarise here. From your comments I 
> gather, this is not a misconfiguration of server or client by myself, is this 
> correct?

As long as you are not using the 'nocto' option on the client mount
options, and you are being careful not to make changes within < 1 second
of each other from different clients then this should all just work out
of the box.

>  It seems, that maybe the writing may be related to a timing issue 
> with ext3 time resolution, however this seems unlikely because I left up to 3 
> seconds between each A and B write access and still found only As. Finally, 
> I'm the first one encountering this problem and reporting to this list?

If you have 3 seconds between the A and B writes, then there is a
problem. The above mentioned tcpdump would really help...

Trond