topic Re: Linux and DSM MPIO? in StoreVirtual Storage

Linux and DSM MPIO?

Paul Hutchings — Thu, 09 Jun 2011 13:31:14 GMT

Is it possible to do DSM MPIO i.e. access a volume via all nodes in a cluster?

I'm pretty sure you can only do this from Windows with the Windows DSM MPIO but I'm not 100% sure so if anyone's able to confirm/clarify that would be great.

Thanks,
Paul

Re: Linux and DSM MPIO?

aqualityplace — Thu, 09 Jun 2011 14:12:46 GMT

Hi Paul

Concurrent access to volume is not a feature that the DSM MPIO provides (to my knowledge) The DSM MPIO driver provides multipathing and direct access to secotrs of data without having to go through the gateway node for a particular volume.

To allow concurrent access to a single volume for multiple hosts the formated file system on the volume must support clustering.

Re: Linux and DSM MPIO?

Paul Hutchings — Thu, 09 Jun 2011 14:30:25 GMT

Sorry I perhaps explained badly.

If I have volume1 and it's network raid10 across node1 and node2 then with the Windows DSM MPIO a connection is made to both node1 and node2 at the same time for volume1.

With Linux (well, certainly vmware) you can do MPIO but the connections would all be to either node1 or node2, not both concurrently.

Can you do anything similar on Linux to what you would do with Windows DSM MPIO?

Re: Linux and DSM MPIO?

aqualityplace — Thu, 09 Jun 2011 14:38:30 GMT

Hi Paul,

I am not sure how this would work in a 2 node cluster. But my understanding is the DSM driver keeps a map of the data so connections dont need to go through a gateway node.

With a 2 node cluster the data is identicle on both nodes for network raid10 volumes so i am not sure if it would decide to load balance between the 2.

if it does it would certainly help improve read performance, wouldnt make much diffenence to writes as the acknologment wouldn't happen untill the write had hit both nodes.

Not sure about any current or future support for a linux DSN driver.

hope this helps

Re: Linux and DSM MPIO?

SUBHAJIT KHANBARMAN_1 — Thu, 09 Jun 2011 14:40:24 GMT

Device Mapper for Linux
-----------------------------

http://h20000.www2.hp.com/bizsupport/TechSupport/SoftwareDescription.jsp?lang=en&cc=us&prodTypeId=12169&prodSeriesId=3559651&prodNameId=3559652&swEnvOID=4004&swLang=13&mode=2&taskId=135&swItem=co-90384-1

Re: Linux and DSM MPIO?

Paul Hutchings — Thu, 09 Jun 2011 15:43:15 GMT

P4000 isn't listed on the supported list for that?

Re: Linux and DSM MPIO?

Jitun — Fri, 10 Jun 2011 04:31:37 GMT

There is no MPIO DSM for Linux and ESX as of now.

Re: Linux and DSM MPIO?

CCC-Monitor — Fri, 21 Oct 2011 14:53:48 GMT

We had tried to setup Multipath on our Linux servers to a P4000 cluster and had quite a few strange problems. After opening a ticket with HP, they confirmed that multipath with Linux is not supported.

Sad but true.

Re: Linux and DSM MPIO?

Bart_Heungens — Fri, 21 Oct 2011 14:59:39 GMT

Yes I can confirm that the DSM MPIO is only available today for Windows...

To obtain better/higher performance for Linux and/or ESX you should follow the best practices by implementing Load Balancing accross multiple NICs... It is not as good as DSM MPIO where you have active connections to all storage nodes, but in a typical 2 or 4 node setup the gain would be less high than with more than 6 nodes...

The document for VMware can be found here

http://h20195.www2.hp.com/V2/GetPDF.aspx/4AA3-6918ENW.pdf

Kr,

Bart