Hi all. I am going through some testing of my multipathed iSCSI devices and I am seeing some longer than expected delays. I am running the latest RHEL 5.4 packages as of this morning. I am seeing the failure of the iSCSI sessions take about 67 seconds. After the iSCSI failure the multipath layer picks up almost immediately. Here is a breakdown of /var/log/messages, I am testing dd while pulling a network cable:
I started the dd at 07:13:51 Cable pulled at: Mar 1 07:14:27 bentCluster-1 kernel: connection4:0: ping timeout of 5 secs expired, recv timeout 5, last rx 4884304, last ping 4889304, now 4894304 ISCIS errors at: Mar 1 07:14:28 bentCluster-1 iscsid: Kernel reported iSCSI connection 4:0 error (1011) state (3) SCSI error and multipath failures at: Mar 1 07:15:35 bentCluster-1 kernel: session2: session recovery timed out after 15 secs Mar 1 07:15:35 bentCluster-1 kernel: sd 3:0:0:1: SCSI error: return code = 0x000f0000 Mar 1 07:15:35 bentCluster-1 kernel: end_request: I/O error, dev sdf, sector 3164079 Mar 1 07:15:35 bentCluster-1 kernel: device-mapper: multipath: Failing path 8:80. And then I/O starts again on the device I am sending I/O down. Finally the other devices fail: Mar 1 07:15:48 bentCluster-1 kernel: device-mapper: multipath: Failing path 8:112. The entire dd took 138 seconds. It looks like the delay is in the iSCSI layer. It took from 07:14:28 to 07:15:35 for the iSCSI session to fail. I am using the timeouts: ● node.session.timeo.replacement_timeout = 15 ● node.conn[0].timeo.noop_out_timeout = 5 ● node.conn[0].timeo.noop_out_interval = 5 http://kbase.redhat.com/faq/docs/DOC-2877 So I guess I have two questions: 1. Based on my timeouts I would think that my session would time out after 15 seconds. Anyone have an idea why is it taking 67 seconds? Am I missing any other timeout values? 2. In a perfect world what is the best case scenario for the failure of my iSCSI session? Thanks in advance. -Ben -- You received this message because you are subscribed to the Google Groups "open-iscsi" group. To post to this group, send email to open-is...@googlegroups.com. To unsubscribe from this group, send email to open-iscsi+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/open-iscsi?hl=en.
