MD1000 connected with two SAS cables in unified mode

Patrick_Fischer at Dell.com Patrick_Fischer at Dell.com
Thu Sep 11 07:22:30 CDT 2008


The MD1000 isn't a multipath device. For this you need a MD3000 (SAS) or MD3000i (ISCSI) which have the raid controller modules in the chassie and aren't managed by a perc controller.
The MD1000 is only a Single Path DAE with option to split it to attach 2 servers or create your arrays over 2 channels for better performance because of using to controller connectors.
With a 500-1000 MB/s it is a fast device for filestransfers...., for i/o's the Md3000/i is the better choice.

-----Original Message-----
From: linux-poweredge-bounces at dell.com [mailto:linux-poweredge-bounces at dell.com] On Behalf Of Mark Watts
Sent: Thursday, September 11, 2008 2:16 PM
To: linux-poweredge-Lists
Subject: Re: MD1000 connected with two SAS cables in unified mode


On Thursday 11 September 2008 13:06:31 Patrick_Fischer at dell.com wrote:
> This configuration is a problem and results in many times in seeing 
> all luns 2 times.
> Two cables are only supported in split mode in all other cases only one.
> It has its cause that it is not in the manual because it doesn't make 
> sence anyway.
>
> -----Original Message-----
> From: linux-poweredge-bounces at dell.com 
> [mailto:linux-poweredge-bounces at dell.com] On Behalf Of Jeff Ewing
> Sent: Thursday, September 11, 2008 1:57 PM
> To: linux-poweredge-Lists
> Subject: MD1000 connected with two SAS cables in unified mode
>
> The MD1000 array on my Redhat server was connected with two SAS cables 
> from the dual port PERC 5 card to each EMM on the MD1000 array.
> It operates in unified mode.
>
> This configuration is not described in the MD1000 Hardware owners 
> manual.
>
> Could this configuration cause problems?
>
> Does this configuration provide any benefit?

Wouldn't this be a case for using dm-multipath to take care of the multiple paths to each LUN?

Mark.


--
Mark Watts BSc RHCE MBCS
Senior Systems Engineer
QinetiQ Applied Technologies
GPG Key: http://www.linux-corner.info/mwatts.gpg



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