From mboxrd@z Thu Jan 1 00:00:00 1970 From: Cory Spitz Date: Fri, 30 Apr 2010 14:25:54 -0500 Subject: [Lustre-devel] question about ldlm_server_glimpse_ast In-Reply-To: References: <4BDAD47E.401@ices.utexas.edu> Message-ID: <4BDB2EC2.7030104@cray.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: lustre-devel@lists.lustre.org Hello. Increasing ldlm_timeout has no effect whatsoever if adaptive timeouts are enabled. See bug 22569. I suggest that you tune up at_min instead. Thanks, -Cory Oleg Drokin wrote: > Hello! > > On Apr 30, 2010, at 9:00 AM, John Hammond wrote: >> I tested a patch which set rq_no_resend = 0 for glimpses, and found that >> clients only had about 6 seconds to reply before eviction. Since >> eviction creates the possibility for data loss, a 6 second timeout was >> deemed too short for production. (With the patch applied, it was easy >> for me to create cases where data was indeed lost.) I was also able to > > Please note that the 6 second timeout is in fact common ldlm_timeout and it's > not just glimpses that are bound by this value. > any ldlm callbacks are required to reply withing this time, so if your > network can have delays of more then this much, you need to consider > increasing ldlm_timeout value (/proc/sys/lustre/ldlm_timeout). > On the other hand if you have a packet loss issue, even if > resending of glimpse ASTs would be present, we don't currently resend > other ASTs so the situation still has a potential for evictions > with subsequent possible data loss. > > Bye, > Oleg > _______________________________________________ > Lustre-devel mailing list > Lustre-devel at lists.lustre.org > http://lists.lustre.org/mailman/listinfo/lustre-devel >