[CentOS] iSCSI best practices

[John Hodrien]

On Mon, 12 Dec 2011, lhecking at users.sourceforge.net wrote:

>
>> Outage is one thing, but having the disk volumes disappear mid-transaction can be detrimental to a file system's health.
>
> To get this back on-topic and closer to the OP's requests, are there any
> particular iscsi settings one should consider to increase resiliency and
> minimise the impact of e.g. a rebooting switch? timeout settings? The
> big disadvantage of iscsi is that you add another layer that can fail
> (compared to having virtual machine images on a local disk).

Make sure you're going through multipath even if you've only got a single link
the iSCSI box.  Just using iscsid and using the devices directly *will* cause
you grief when you have failures.  If you go via multipath the failures are
masked, and it all behaves as you'd hope.

jh