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Hi Karl,<BR>
<BR>
I have not encountered stale file handles with NFSv3 migration with streamed write failures. And I'm pretty certain that at least some of the time I wait more than 90 sec for the migration to happen before declaring failure and migrating back to the original server.<BR>
<BR>
I would first like to determine where the problem is. Since streamed reads and writes work across migrations for NFSv3 over UDP, I think the problem is in the tcp layer. But, since streamed reads work across migrations for NFSv3 over TCP, I'm left wondering what is the difference between how the NFSv3 reads and writes are handled. <BR>
<BR>
Someone with more NFS internals experience maybe could point out where the problem is occurring and propose a workaround or fix. Anyone have any suggestions?<BR>
<BR>
Cheers,<BR>
Bob Haxo<BR>
SGI<BR>
<BR>
On Tue, 2009-05-19 at 21:04 -0500, Karl Katzke wrote:
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<FONT COLOR="#000000">Bob - </FONT>
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<FONT COLOR="#000000">No, I don't, but I'm very interested in your progress. I also have it (sometimes) working over NFSv4 but ... also sometimes not working. The other issue is that after a HA migration, we sometimes see the file handles on the client machines hit a 90 second timeout and go stale; restarting the NFS client on the machines will clear this problem and bring back the file handles. Have you hit that problem? </FONT>
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<FONT COLOR="#000000">UDP is undesirable for us because we're on a large university network that sometimes drops packets, and I'm not aware of a way to checksum tranfers automatically to avoid corruption. </FONT>
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<FONT COLOR="#000000">I'm a bit new to NFS (especially v4), so I'm sorry that I can't help any more than that... and to make matters worse, I've had to shelf testing on HAE this week due to some other urgent configurations and moves that need to happen. </FONT>
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<FONT COLOR="#000000">Please keep me posted on your progress and let me know what configurations you've tried (besides UDP)... </FONT>
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<FONT COLOR="#000000">Thanks,</FONT>
<FONT COLOR="#000000">-K</FONT>
<FONT COLOR="#000000">---</FONT>
<FONT COLOR="#000000">Karl Katzke</FONT>
<FONT COLOR="#000000">Systems Analyst II</FONT>
<FONT COLOR="#000000">TAMU - DRGS</FONT>
<FONT COLOR="#000000">>>> Bob Haxo <<A HREF="mailto:bhaxo@sgi.com">bhaxo@sgi.com</A>> 05/19/09 5:16 PM >>></FONT>
<FONT COLOR="#000000">Greetings,</FONT>
<FONT COLOR="#000000">I find that streamed writes fail with migration for NFS v3 over TCP.</FONT>
<FONT COLOR="#000000">Not every time, but almost every time.</FONT>
<FONT COLOR="#000000">Streamed writes continue nicely across many migrations for NFS v3 over</FONT>
<FONT COLOR="#000000">UDP.</FONT>
<FONT COLOR="#000000">With TCP, writes continue with migration back to the initial server.</FONT>
<FONT COLOR="#000000">Does anyone have HA NFS migrations working for NFS over TCP?</FONT>
<FONT COLOR="#000000">Suggestions?</FONT>
<FONT COLOR="#000000">Cheers,</FONT>
<FONT COLOR="#000000">Bob haxo</FONT>
<FONT COLOR="#000000">SGI</FONT>
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