Set up a multi path SAS link between c3000 enclosure and MSA array on RHEL6

Posted on 2011-04-20
Last Modified: 2012-06-27
Hi Experts,

We are trying to set a storage link between an HP c3000 blade system (2 servers, 2 3Gb SAS switches) and an MSA array (2 controllers).

We also have 4 SAS links :

- MSA controller 1 port 1 to 3Gb SAS 1 port 1
- MSA controller 1 port 2 to 3Gb SAS 2 port 1
- MSA controller 2 port 1 to 3Gb SAS 1 port 2
- MSA controller 2 port 2 to 3Gb SAS 2 port 2

Servers are running RHEL 6 and domino messaging.
Array is splitted into 2 logical volumes : one per server (no shared storage)

We are experiencing troubles testing storage links redundancy.
RHEL experiences I/O errors as soon as some links are missing.

What is the proper way to set a fully redundant storage path (multipath) with RHEL6 ?

Any help will be appreciated (migration impared)

Best regards,
Question by:acharreau
    LVL 55

    Expert Comment

    According to the following doc HP's multipath mapper is replaced by the OS generic one so you'll have to sign up to HP SPOCK and go through The Native Linux Device Mapper Multipath reference guide to see how to to configure.

    I'm a bit worried when you say "some links are missing", one link missing is covered by redundancy, two missing is considered a double fault so is not covered. Taking both paths off a controller does not cause failover.
    LVL 31

    Expert Comment

    There is HP device mapper and there is Red Hat based system.  Which one was used to map?
    LVL 55

    Accepted Solution

    Missed my link -

    Note RHEL6 isn't listed...

    This is the final release of HP Device Mapper Multipath Enablement Kit.  A new Native Linux Device-Mapper Multipath reference guide has been put together.  User can follow the new guide to setup linux Device Mapper Multipath for HP arrays.  The guide will be updated as new arrays are released and with other relevant up-to-date information.  The Native Linux Device Mapper Multipath reference guide can be found on SPOCK both internally and externally at  On the web site, look for “Application Notes” on left hand side and click on “Solutions: Linux”.

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