From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nic Henke Date: Thu, 12 May 2011 09:57:41 -0500 Subject: [Lustre-devel] replacing Lustre pings with LNet Peer Health Message-ID: <4DCBF565.3060602@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 Just floating an idea... I'd much appreciate any feedback Given bug 12471 where the ptlrpc pinger traffic on a large system can approach the ridiculous (2.6M pings every 75s for 160 OSTs and 16K clients), I'd like to consider getting rid of the pings entirely. The idea would be to extend the idea in the attached patch where we add an upper layer callback for lnet_notify() signaling a peer going down or up. The ptlrpc pinger code would be then changed to record the 'down' event for an import/export which would then start an eviction timer that started when the LNet peer was last_alive. If the nodes comes 'up' before the timer expires, no eviction. The eviction code would then only operate on nodes with 'down' events and trusting that the rest are all ok and functional. Eric - I know this doesn't get us that far down the road toward your new health network, but does solve a near term issue with pinger rates on large systems. Issues... - lacks "proof" that peer nodes ptlrpc queues are moving forward, but not really sure that is all that important in terms of pinger evictions. - LNet peer health is a bit "weird" in that it requires an upper layer sending a packet to trigger a node moving back to 'up'. We would need to address this for proper LNet peer health as it is. - Might need some beefing up of the standard LNDs to ensure we have good peer health data. Thoughts ? Nic -------------- next part -------------- A non-text attachment was scrubbed... Name: register_notify.diff Type: text/x-patch Size: 6030 bytes Desc: not available URL: