Multiple HBAs on a single expander

[Haringat]

Is it possible to hook up multiple HBAs from different hosts to the same SAS expander to share the drives between the different systems?

 

[kapone]

...

 

[Rand__]

sure, how do you think external jbod chassis do it?

 

[Haringat]

@Rand__
I didn't know they could do that. I did know that you can attach multiple HBAs from the same host (that is what the literature says when explaining multi-path I/O) but it is nowhere written whether it works for different hosts. But thank you for your answer.

 

[msg7086]

Wait. You are saying attaching multiple HBA from different hosts to share drives? How?

So let's say you have host A and host B, and you have drive X and drive Y.

Now you want host A and B to access drive X and Y at the same time?

 

[Haringat]

Now you want host A and B to access drive X and Y at the same time?

That's the plan. I mean, it works with network mounts (which effectively have to handle it somehow too) and other forms of NAS access and as far as I understood Rands answer, it works with SAS too so I will try it and let you know if it does (gonna take up to a month for the HBAs to arrive though)

 

[msg7086]

If memory serves me correct, with iSCSI and FC you can share drives with different hosts. Not sure about direct HBA connections. However it's obvious that you can't use the same drive by different hosts at the same time. It has to be set up as failover. The file system has to be unmounted by one host before being mounted by another host.

 

[Haringat]

ok that would make it a bit uncomfortable to use but would still be fine by me.

 

[gregsachs]

Two different possibilities, as I understand it.
1: Zone the expander. This logically splits the expander into two. Not supported by all; I tried querying the zone against a xyratex xb-1235 and it said not supported. A SAS switch can also do this I believe.
2: Microsoft does/did support shared sas cluster storage, where an external JBOD is connected to multiple hosts. Not sure if this extended past server 2012.

Shared storage in a cluster

Solution: After trying and testing, we have come to the conclusion it can't be done...But, while trying to find a cheap and possibly free solution, I came

community.spiceworks.com

 

[i386]

how do you think external jbod chassis do it

They use dual port sas drives and two expandeers?

A SAS switch can also do this I believe.

A sas switch are cascaded expanders with sas zoning enabled/configured

Microsoft does/did support shared sas cluster storage, where an external JBOD is connected to multiple hosts.

Microsoft supported this storage spaces setup with dual ported sas devices and dual expanders

 

[Rand__]

They use dual port sas drives and two expandeers?

And each of the two expanders can take over all drives in case the other ones brake down... but yes, thats much more precise