[CentOS] iSCSI Question

Steven Crothers steven.crothers at gmail.com
Sat Nov 17 04:02:19 UTC 2012


Hey everyone,

Is anybody aware of a /true/ active/active multi-head and multi-target
clustered iSCSI daemon?

IE:

Server 1:
Hostname: host1.test.com
IP Address: 10.0.0.1

Server 2:
Hostname: host2.test.com
IP Address: 10.0.0.2

Then they would utilize a CLVM disk between them, let's call that VG "disk"
and then directly map each LUN (1,2,3,4,etc) to LV's named 1,2,3,4,... and
so on.

That would essentially make both host1 and host2 identical iSCSI targets.
So I could hook up 30 servers to each LUN on each host1 and host2 (assuming
those block devices had a cluster aware filesystem on them).

However, what I wan't to accomplish is true active/active MPIO utilizing
the dm driver to combine LUN 1 from both host1 and host2 as a single
/dev/dm-0 device in active/active mode.

This would allow me to multipath across multiple fabrics, develop true high
availability and increase my throughput significantly.

Any idea of an iscsi tgtd that supports this? As far as I can tell, none do
(that I can find). I know some proprietary vendors have this type of
functionality, which may or may not be using iSCSI code (but that's a whole
set of arguments for later..).

Ultimately, my goal is this.

I want to take my existing Ceph cluster, expose a handful of RBDs from it
to two iSCSI heads running C6 or RHEL6 or what have you, so I can use my
inexpensive storage built on Linux -- for my Windows 2008 machines.

Thoughts?


Steven Crothers
steven.crothers at gmail.com


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