[dm-devel] info on enabling only one path with rdac and DS4700
Johannes Hirte
hirtejs at idmt.fraunhofer.de
Tue Nov 15 20:10:22 UTC 2011
On Tuesday 15 November 2011 16:34:20 Gianluca Cecchi wrote:
> Hello,
> with RH EL 5.7 x86_64 and updates:
> # uname -r
> 2.6.18-274.7.1.el5
> # rpm -q device-mapper-multipath
> device-mapper-multipath-0.4.7-46.el5_7.1
>
> I'm on a IBM HS21 blade connected to a DS4700 storage array.
> Without doing nothing in multipath.conf but blacklisting the internal
> disk, I get this kind of configuration:
> # multipath -l
> mpath1 (3600a0b80005012440000093e4a55cf33) dm-6 IBM,1814 FAStT
> [size=3.4T][features=1 queue_if_no_path][hwhandler=1 rdac][rw]
> \_ round-robin 0 [prio=0][active]
> \_ 3:0:0:1 sdb 8:16 [active][undef]
> \_ 4:0:0:1 sdc 8:32 [active][undef]
> \_ round-robin 0 [prio=0][enabled]
> \_ 3:0:1:1 sdd 8:48 [active][undef]
> \_ 4:0:1:1 sde 8:64 [active][undef]
>
> Is there any config option I can force to use only one path at a time
> in the active controller, instead of two (sdb and sdc in my case) in
> round robin as I see in iostat?
>
> Also, I noticed that output with "-ll" shows "200" as priority of
> paths for the active controller, while "-l" shows 0 for both (see
> above)...
> Is this a bug or expected difference due to command different switch/verbosity?
> (I see similar behaviour also with another server connected to a
> DS6800 storage array)
> # multipath -ll
> mpath1 (3600a0b80005012440000093e4a55cf33) dm-6 IBM,1814 FAStT
> [size=3.4T][features=1 queue_if_no_path][hwhandler=1 rdac][rw]
> \_ round-robin 0 [prio=200][active]
> \_ 3:0:0:1 sdb 8:16 [active][ready]
> \_ 4:0:0:1 sdc 8:32 [active][ready]
> \_ round-robin 0 [prio=0][enabled]
> \_ 3:0:1:1 sdd 8:48 [active][ghost]
> \_ 4:0:1:1 sde 8:64 [active][ghost]
>
> I would like to use default multipath instead of LSI provided rdac, found at
> http://www.lsi.com/sep/Pages/rdac/ds4000.aspx
> version 09.03.0C05.0504 , dated 7/18/2011 with:
> New linux kernel versions supported with this release:
> - SLES 10-SP3: 2.6.16.60-0.54.5
> - SLES 10-SP4: 2.6.16.60-0.85.1
> - SLES 11.1 : 2.6.32.12-0.7
> - RHEL5-u5 : 2.6.18-194
> - RHEL5-u6 : 2.6.18-238
> - RHEL6 : 2.6.32-71
>
> In fact I'm using 2.6.18-274.7.1.el5 that is not listed...
> Any known cons in using device-mapper-multipath with IBM,1814?
The rdac driver from LSI won't even compile, IIRC. With the dm-multipath driver you have to disable AVT on the DS4700. Otherwise the rdac module won't work with the storage.
regards,
Johannes
More information about the dm-devel
mailing list