Re: Device mapper multipathing

Can you provide the storage maker and model?

Normally Storage vendors provides failover policies such as

# For EVA A/A arrays
device {

        vendor                  "HP|COMPAQ"
        product                 "HSV1[01]1
\(C\)COMPAQ|HSV[2][01]0|HSV300|HSV4[05]0"
        path_grouping_policy    group_by_prio
        getuid_callout          "/lib/udev/scsi_id -g -u /dev/%n"
        path_checker            tur
        path_selector           "round-robin 0"
        prio                    alua
        rr_weight               uniform
        failback                immediate
        hardware_handler        "0"
        no_path_retry           18
        rr_min_io               100

## Device attributes for EMC CLARiiON device {

     vendor                 "DGC "
     product                "*"
     path_grouping_policy   group_by_prio
     getuid_callout         "/sbin/scsi_id -g -u -s /block/%n"
     prio_callout           "/sbin/mpath_prio_emc /dev/%n"
     path_checker           emc_clariion
     path_selector          "round-robin 0"
     features               "1 queue_if_no_path"
     no_path_retry          300
     hardware_handler       "1 emc"
     failback               immediate

On Tue, Jan 11, 2011 at 6:58 AM, Zhu,Chao <zhuchao_at_gmail.com> wrote:

> not sure if anyone else has updated this thread since it was posted;
> We ran into issue of delayed path failover (when one path dies/disabled,
> all IO hang for 30sec-2 min);
> it wasn't that optimal to have that time IO totally freezed;
>
> We were using redhat 5.4 and also tried oracle enterprise kernel;
>
> Would be great to hear more inputs;
>
> Thx
>
>
>
> On Wed, Nov 29, 2006 at 7:08 PM, Luca Canali <Luca.Canali_at_cern.ch> wrote:
>
>> Hi,
>>
>> Is anybody who has used device mapper for Linux willing to share their
>> experience?
>>
>> I have been using Qlogic multipathing so far with the qla2300_conf
>> module on RHEL3. No problem with it, but I am moving to RHEL4 and the
>> needed qla2xxx_conf module is missing from their rmps distribution. So
>> instead I have done a few tests with device mapper multipathing, seems
>> to work fine so far, but nothing can beat real world experience.
>>
>> Thanks,
>> L.
>> --
>> http://www.freelists.org/webpage/oracle-l
>>
>>
>>
>
>
> --
> Regards
> Zhu Chao
>
>
>

--
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