Thanks Krzysztof . I modified my /etc/multipath.conf file as per your
suggestion/example but after the reboot the server goes into single
user mode. Careful examination points to the fact that I forgot to
delete the line ` wwid "*" ` in the blacklist definition. Need to
fix that problem and get back with the final outcome.
Cheers,
Win
> The preffered path means, that it's not entirely an Active/Active
> configuration.
> You probably have LUNs on both controllers - and - system can see LUNs
> thru both of them, but only one path (controller) is ready to be active
> and send/receive data.
>
> Before RHEL 5 you should use IBM RDAC driver (configuration was simple).
> Now RDAC implementation is in device-multipathing.
>
> You should see the the
> /usr/share/doc/device-mapper-multipath-0.4.7/multipath.conf.defaults and
> look for device configuration:
>
> device {
> vendor "IBM"
> product "1722-600"
> [...]
> }
>
>
> We currently use:
>
> device {
> # for DS4700
> vendor "IBM"
> product "1722-600"
> prio_callout "/sbin/mpath_prio_rdac /dev/%n"
> features "1 queue_if_no_path"
> hardware_handler "1 rdac"
> failback immediate
> rr_weight uniform
> no_path_retry 300
> path_checker rdac
> }
>
> With defaults:
>
> defaults {
> udev_dir /dev
> getuid_callout "/sbin/scsi_id -g -u -s /block/%n"
> path_checker rdac
> rr_min_io 1000
> max_fds 8192
> user_friendly_names yes
> }
>
> The preffered path is changed by a array if there is no way to use the
> chosen prefferd path. RHEL is choosing the right path with the priorities
> (prio_callout "/sbin/mpath_prio_rdac /dev/%n").
>
> BTW:
> You can have all active paths on DS8xxx but not on DS4xxx series.
>
> Best Regards
> Krzysztof Mazurek
>
>
> [email protected] -- zapisano w dniu 2009-07-08 14:32:55:
>
>> Win Htin <[email protected]>
>> Wysłane przez: [email protected]
>>
>> 2009-07-08 14:32
>>
>> Odpowiedz użytkownikowi
>> "Red Hat Enterprise Linux 5 \(Tikanga\) discussion mailing-list"
>> <[email protected]>
>>
>> Do
>>
>> [email protected]
>>
>> DW
>>
>> Temat
>>
>> [rhelv5-list] Dynamic Multipathing boot disks - Part 2
>>
>> Hi folks,
>>
>> Thanks to Tom's help, I have Dynamic Multipathing up and running for
>> my boot disks.
>>
>> My next question is, how can I configure the boot disk to stay on the
>> controller that I specify? Currently, the Storage Array (IBM DS4700,
>> Active/Active controllers) starts complaining the logical drive is not
>> on preferred path (controller A). If I change the preferred path back
>> to controller A, it immediately goes back to controller B. For the
>> other servers, I have modified QLogic driver installed kernels and
>> assign preferred paths through qlremote/SanSurfer combo.
>>
>> Your help is much appreciated. TIA.
>>
>> Cheers,
>> Win
>>
>> _______________________________________________
>> rhelv5-list mailing list
>> [email protected]
>> https://www.redhat.com/mailman/listinfo/rhelv5-list
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