Question about MD multipathing

Question about MD multipathing

[martin.lonkwitz.sp]

Hello  !
 
could anyone say if active/passive means that there is realy no (zero)
traffic on the passive path of the md device ? 
Cause I have problems with active/passiv storage (storagetek D240) while
Lun's jump to the passiv controller of the storage cause of traffic
comes to this one :/
Dones anyone can suggest another solution for active/passive storage
that works with linux kernel 2.4 and 2.6 ?
 
Thank you for your help !
 
regards,
         Martin
 
Please answer to: martin.lonkwitz.sp __AT___ lhsystems.com
 
 

Re: Question about MD multipathing

[Lars Marowsky-Bree]

On 2005-08-03T14:14:56, martin.lonkwitz.sp@lhsystems.com wrote:

> Cause I have problems with active/passiv storage (storagetek D240) while
> Lun's jump to the passiv controller of the storage cause of traffic
> comes to this one :/
> Dones anyone can suggest another solution for active/passive storage
> that works with linux kernel 2.4 and 2.6 ?

You should use DM multipath. md multipath isn't going to perform well
for you in 2.4 (unless you're using the SLES8 kernel, which is hacked up
quite a bit).

With 2.6, Device-Mapper has been choosen for the multipath IO to be
implemented in.



Sincerely,
    Lars Marowsky-Brée <lmb@suse.de>

-- 
High Availability & Clustering
SUSE Labs, Research and Development
SUSE LINUX Products GmbH - A Novell Business	 -- Charles Darwin
"Ignorance more frequently begets confidence than does knowledge"

RE: Question about MD multipathing

[martin.lonkwitz.sp]

Hello Lars,

Thank you very much for your mail.
Well, unfortunately I don't have a choice and musst use kernel 2.4 :-(
But therefore we use mostly Suse :)
Any more options ? We tried the qlogic fail-over driver. But it looks like
that this driver are unable to handle the way over 2 fabrics to a lun.

Regards,
          Martin Lonkwitz


-----Original Message-----
From: Lars Marowsky-Bree [mailto:lmb@suse.de] 
Sent: Donnerstag, 4. August 2005 14:30
To: LONKWITZ, MARTIN; linux-raid@vger.kernel.org
Subject: Re: Question about MD multipathing

On 2005-08-03T14:14:56, martin.lonkwitz.sp@lhsystems.com wrote:

> Cause I have problems with active/passiv storage (storagetek D240) 
> while Lun's jump to the passiv controller of the storage cause of 
> traffic comes to this one :/ Dones anyone can suggest another solution 
> for active/passive storage that works with linux kernel 2.4 and 2.6 ?

You should use DM multipath. md multipath isn't going to perform well for you in 2.4 (unless you're using the SLES8 kernel, which is hacked up quite a bit).

With 2.6, Device-Mapper has been choosen for the multipath IO to be implemented in.



Sincerely,
    Lars Marowsky-Brée <lmb@suse.de>

--
High Availability & Clustering
SUSE Labs, Research and Development
SUSE LINUX Products GmbH - A Novell Business	 -- Charles Darwin
"Ignorance more frequently begets confidence than does knowledge"

Re: Question about MD multipathing

[Lars Marowsky-Bree]

On 2005-08-04T14:46:28, martin.lonkwitz.sp@lhsystems.com wrote:

> Hello Lars,
> 
> Thank you very much for your mail.
> Well, unfortunately I don't have a choice and musst use kernel 2.4 :-(
> But therefore we use mostly Suse :)

OK, md multipath works rather well in the latest SLES8 2.4 kernel
update.

Just don't set all paths to active, add the passive ones as spares, and
then you will have a true active/passive scenario.

> Any more options ? We tried the qlogic fail-over driver. But it looks like
> that this driver are unable to handle the way over 2 fabrics to a lun.

No idea, I don't use qlogic internal multipathing at all.


Sincerely,
    Lars Marowsky-Brée <lmb@suse.de>

-- 
High Availability & Clustering
SUSE Labs, Research and Development
SUSE LINUX Products GmbH - A Novell Business	 -- Charles Darwin
"Ignorance more frequently begets confidence than does knowledge"