I have a bunch of VM servers running Xen VMs from iSCSI LUNs mounted in the Dom0 host via Open-iSCSI. It's just a simple single-path setup (redundancy is on the target side via clustered storage and a virtual IP)
I'm considering using the settings from the Open-iSCSI README for iSCSI root, since that's basically what it is:
8.2 iSCSI settings for iSCSI root --------------------------------- When accessing the root parition directly through a iSCSI disk, the iSCSI timers should be set so that iSCSI layer has several chances to try to re-establish a session and so that commands are not quickly requeued to the SCSI layer. Basically you want theopposite of when using dm-multipath. For this setup, you can turn off iSCSI pings by setting: node.conn.timeo.noop_out_interval = 0 node.conn.timeo.noop_out_timeout= 0 And you can turn the replacement_timer to a very long value: node.session.timeo.replacement_timeout = 86400
Are there any other recommended settings for running VMs with a root on an iSCSI LUN I should think about?