Question about dm-multipath and Sun StorageTek 6140

Question about dm-multipath and Sun StorageTek 6140

[Ralf Aumüller]

Hallo,

I have the following questions about dm-multipathing:

- is it true that I need a hardware-specific handler for arrays running
  with active/passive controllers (like the Sun StorageTek 6140) to
  get the the LUN trespassing working?

- did someone get the Sun StorageTek 6140 configured for dm-multipath?
  (so that the LUN trespassing works)

Thank's in advance,

Ralf

(I a also asked these question on the RHEL-list but didn't get an answer
so I try it here again)

Re: Question about dm-multipath and Sun StorageTek 6140

[Yury Konovalov]

Hi Ralf,

2007/2/9, Ralf Aumüller <Ralf.Aumueller@informatik.uni-stuttgart.de>:

> - is it true that I need a hardware-specific handler for arrays running
>   with active/passive controllers (like the Sun StorageTek 6140) to
>   get the the LUN trespassing working?

It's true only for non-AVT mode (set host type to Linux to turn AVT mode on)

> - did someone get the Sun StorageTek 6140 configured for dm-multipath?
>   (so that the LUN trespassing works)

It should work as it does for other boxes with LSILogic controllers.

path_grouping_policy    group_by_prio
path_checker            tur
prio_callout            "/sbin/mpath_prio_tpc /dev/%n"

-- 
Best Regards.

Re: Question about dm-multipath and Sun StorageTek 6140

[Eckebrecht von Pappenheim]

Hi Yury,

thanks for Your hints, I had the same problem an figured it out now.

>> - is it true that I need a hardware-specific handler for arrays running
>>   with active/passive controllers (like the Sun StorageTek 6140) to
>>   get the the LUN trespassing working?
> 
> It's true only for non-AVT mode (set host type to Linux to turn AVT mode on)

at least for the 6140 this is not correct. It sets the mode to RDAC for the
Sun-RDAC-Driver ( http://www.sun.com/download/products.xml?id=44d12115 ).

You have to choose 'Solaris (with Veritas DMP or other)' (named SOLAVT in the
CLI) to enable AVT.
 
>> - did someone get the Sun StorageTek 6140 configured for dm-multipath?
>>   (so that the LUN trespassing works)
> 
> It should work as it does for other boxes with LSILogic controllers.
> 
> path_grouping_policy    group_by_prio
> path_checker            tur
> prio_callout            "/sbin/mpath_prio_tpc /dev/%n"

Correct, with this setup and AVT enabled LUN trespassing works as designed:

multipathd> show maps topo
reload: Raid5_for_IMAP-Volume (3600a0b800026851e000014e245bf1906) dm-0
SUN,CSM200_R
[size=1.4T][features=0][hwhandler=0]
\_ round-robin 0 [prio=12][active]
 \_ 7:0:2:1 sdah 66:16  [active][ready]
 \_ 6:0:0:1 sdd  8:48   [active][ready]
\_ round-robin 0 [prio=2][enabled]
 \_ 6:0:2:1 sdn  8:208  [active][ready]
 \_ 7:0:0:1 sdx  65:112 [active][ready]

and after failure of preferred controller:

multipathd> show maps topo
reload: Raid5_for_IMAP-Volume (3600a0b800026851e000014e245bf1906) dm-0
SUN,CSM200_R
[size=1.4T][features=0][hwhandler=0]
\_ round-robin 0 [prio=0][enabled]
 \_ 7:0:2:1 sdah 66:16  [failed][faulty]
 \_ 6:0:0:1 sdd  8:48   [failed][faulty]
\_ round-robin 0 [prio=6][active]
 \_ 6:0:2:1 sdn  8:208  [active][ready] 
 \_ 7:0:0:1 sdx  65:112 [active][ready] 

Great software!

Regards,
Eckebrecht

-- 
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Re: Question about dm-multipath and Sun StorageTek 6140

[Yury Konovalov]

Hi Eckebrecht,

2007/2/14, Eckebrecht von Pappenheim <evp@heise.de>:
> > It's true only for non-AVT mode (set host type to Linux to turn AVT mode
> on)
>
> at least for the 6140 this is not correct. It sets the mode to RDAC for the
> Sun-RDAC-Driver ( http://www.sun.com/download/products.xml?id=44d12115 ).
>
> You have to choose 'Solaris (with Veritas DMP or other)' (named SOLAVT in
> the
> CLI) to enable AVT.

You're right. It seems that Sun uses different host types from those
used by IBM http://sunsolve.sun.com/search/document.do?assetkey=1-9-83529-1
-----
...
Linux: This setting is for all Linux OE's using explicit failover via
either STM for linux or the mpp(RDAC) driver.
...
Solaris (with Veritas DMP): This is for Solaris hosts using Symantec
Veritas DMP driver for implicit failover.
...
----

Following Sun terminology, host type with implicit failover should be
used for dm multipathing. At least until (if ever) rdac hwhandler will
be implemented in device mapper.


All best wishes,
Yury.