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Our cluster was supplied with two IBM DS3400 RAID arrays connected with fibre channel. Both are old and one is failing so we bought an IBM
V3700 to replace it. The V3700 complained that we were using the IBM’s RDAC driver (true) and we were advised to change to using Linux multipath. I’ve done that but the default configuration for the DS3400s is:
device {
vendor IBM
product 1726-4xx
path_checker rdac
features 1 queue_if_no_path
hardware_handler 1 rdac
prio_callout /sbin/mpath_prio_rdac /dev/%n
no_path_retry 300
rr_min_io 1000
The V3700 is still complaining and I note the “path checker rdac” and mpath_prio_rdac lines. Is this rdac the same as IBM’s RDAC, and if so how can I get rid of it?

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2 thoughts on - Multipathd

  • at least patch CentOS 5. 5.3 is a snapshot from 6 years ago (2009), there’ve been 6 years of updates to CentOS 5 since that point, both security and bug fixes. `yum update` would bring you up to CentOS the
    .11 update plus security/bug fixes since.

  • Am 04.02.2015 um 15:02 schrieb Rushton Martin:

    So you switched from IBM’s proprietary multipath driver to the native Linux multipathing. Correct?

    The right settings are documented here:

    Yoi should be a little more specific about the conflict you see.

    The DS3400 is an OEM product, provided by NetApp. RDAC is the the name of the hardware access type originally for LSI Corp controllers, later on NetApp.

    mpath_prio_rdac is code from the Linux kernel.

    Update! Not upgrade. That old piece of software is full of well known severe security issues and bugs already fixed. There is not really an excuse to not properly maintain a system.