[dm-devel] [PATCH] multipath-tools: adapt HITACHI/OPEN- config to work with alua and multibus

[Xose Vazquez Perez]

On 5/31/23 17:49, Martin Wilck wrote:

> On Wed, 2023-05-31 at 15:57 +0200, Xose Vazquez Perez wrote:
>> ALUA is needed by Hitachi Global-Active Device (GAD):
>> https://knowledge.hitachivantara.com/Documents/Management_Software/SVOS/8.1/Global-Active_Device/Overview_of_global-active_device

> Thanks, but where exactly did you find this information in the linked
> document? I don't see ALUA mentioned. Unfortunately Hitachi chose to
> use non-standard terminology... 

No public info, personal e-mail from Matthias:

"We have also a config for ALUA. It is used for hardware copy between two
arrays and the server should only use the local paths:

SLES 12 SP2 ALUA:

device {
            vendor               "HITACHI"
            product              "OPEN-.*"
            features             "0"
            path_grouping_policy group_by_prio
            prio                 alua
            path_selector        "round-robin 0"
            rr_weight            uniform
            no_path_retry        1
            rr_min_io            100
            path_checker         directio
            failback             immediate
      }
"

 > Is ALUA always active / supported in these arrays?

Disable by default. And it is only needed with GAD setup:

Array settings:
"ALUA Mode" Enabled
"Path Mode" ALUA
"ALUA Permitted" YES
"ALUA Settable" YES
"Target Port Asymmetric Access State" Active/Optimized

Same case as HUAWEI https://github.com/opensvc/multipath-tools/commit/9283fa6663ad908fd0419edcef4795fbbbe9f09d

"no_path_retry 10" comes from: 
https://knowledge.hitachivantara.com/Documents/Management_Software/SVOS/9.8.6/Volume_Management_-_VSP_5000_Series/Host_Attachment/05_Red_Hat_Linux_configuration_and_attachment#Device_Mapper_(DM)_Multipath_configuration.0D.0A____for_Red_Hat_Linux