From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Christie Subject: Re: Multipath / iSCSI issues Date: Sun, 24 Feb 2013 17:50:00 -0600 Message-ID: <512AA728.7040507@cs.wisc.edu> References: Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: device-mapper development Cc: Devin List-Id: dm-devel.ids On 02/24/2013 01:15 PM, Devin wrote: > > I am running Oracle Enterprise Linux 5.8 (which is really just Redhat). > I am using Multipath and I have LUNS presented to me via iSCSI from a > Hitachi SAN. I have the NICS bonded using the Linux bonding driver and > using Active-Backup mode. I notice that when I loose a switch or > connection to one of the switches that multipath freezes for at least 60 > seconds before it starts to respond again. Also it appears that IO being > generated freezes until multipath responds again, this pause up to 60 > seconds is causing my Oracle instances to crash. > > I have not been able to easily find what settings i could possibly > change to make it fail to a new path faster. It almost seems like it's > taking multipath a bit to fail all IO to a new path that is working. > > Is there any information that might be useful for me that I can check on > either the multipath side or the iSCSI side to see what is causing the > issue??? > What iscsi driver are you using? If you are using software iscsi that comes with OEL 5.8 what are our node.session.timeo.replacement_timeout, .timeo.noop_out_timeout and .timeo.noop_out_interval. And what is your scsi command timeout. You can see that by doing: cat /sys/block/sdX/device/timeout