Device-mapper-multipath RDAC

Device-mapper-multipath RDAC

[Nuno Fernandes]

hello,

Just a question:

With recent support for rdac hardware handler in kernel 2.6.23-rc7, what 
configuration should be in storage DS4700? AVT (Automatic Volume transfer) 
turned on or off?

When it's turned on, luns keep on jumping from controller to controller..

Thanks
Nuno Fernandes

RE: Device-mapper-multipath RDAC

[James Fillman]

I've just finished going through the process of getting our SAN gear
working on RHEL5 with multipathing. I've got a Sun 6140 which I think is
very similar to yours. They both are from ingenia. You'll want to use a
*NON* AVT host type on the SAN.  I've set mine to type "Linux" and it
works great.

cheers,
--james

-----Original Message-----
From: dm-devel-bounces@redhat.com [mailto:dm-devel-bounces@redhat.com]
On Behalf Of Nuno Fernandes
Sent: Monday, September 24, 2007 9:06 AM
To: device-mapper development
Subject: [dm-devel] Device-mapper-multipath RDAC

hello,

Just a question:

With recent support for rdac hardware handler in kernel 2.6.23-rc7, what

configuration should be in storage DS4700? AVT (Automatic Volume
transfer) 
turned on or off?

When it's turned on, luns keep on jumping from controller to
controller..

Thanks
Nuno Fernandes

--
dm-devel mailing list
dm-devel@redhat.com
https://www.redhat.com/mailman/listinfo/dm-devel

Re: Device-mapper-multipath RDAC

[Nuno Fernandes]

I don't know Sun 6140, but for DS4700 the default for Linux is AVT enabled. 
I've disabled using scripts from storage manager.

What kernel version are u using? What about multipath tools? Can you send me 
your /etc/multipath.conf.

Have you tried to disconnect all fibres to the active controller of your SUN 
6140 to see if the LUNS jumps to the other controller?

Thanks
Nuno Fernandes


On Monday 24 September 2007 18:01:15 James Fillman wrote:
> I've just finished going through the process of getting our SAN gear
> working on RHEL5 with multipathing. I've got a Sun 6140 which I think is
> very similar to yours. They both are from ingenia. You'll want to use a
> *NON* AVT host type on the SAN.  I've set mine to type "Linux" and it
> works great.
>
> cheers,
> --james
>
> -----Original Message-----
> From: dm-devel-bounces@redhat.com [mailto:dm-devel-bounces@redhat.com]
> On Behalf Of Nuno Fernandes
> Sent: Monday, September 24, 2007 9:06 AM
> To: device-mapper development
> Subject: [dm-devel] Device-mapper-multipath RDAC
>
> hello,
>
> Just a question:
>
> With recent support for rdac hardware handler in kernel 2.6.23-rc7, what
>
> configuration should be in storage DS4700? AVT (Automatic Volume
> transfer)
> turned on or off?
>
> When it's turned on, luns keep on jumping from controller to
> controller..
>
> Thanks
> Nuno Fernandes
>
> --
> dm-devel mailing list
> dm-devel@redhat.com
> https://www.redhat.com/mailman/listinfo/dm-devel
>
>
>
> --
> dm-devel mailing list
> dm-devel@redhat.com
> https://www.redhat.com/mailman/listinfo/dm-devel

Re: Device-mapper-multipath RDAC

[Chandra Seetharaman]

On Mon, 2007-09-24 at 17:06 +0100, Nuno Fernandes wrote:
> hello,
> 
> Just a question:
> 
> With recent support for rdac hardware handler in kernel 2.6.23-rc7, what 
> configuration should be in storage DS4700? AVT (Automatic Volume transfer) 
> turned on or off?

Hardware handler is needed only for RDAC mode, AVT would work without
the hardware handler.

The decision to use RDAC or AVT depends on your configuration.

> 
> When it's turned on, luns keep on jumping from controller to controller..

dm-multipath will use the other path (in AVT mode, IOW, jump) only if
I/O in the current path fails.
> 
> Thanks
> Nuno Fernandes
> 
> --
> dm-devel mailing list
> dm-devel@redhat.com
> https://www.redhat.com/mailman/listinfo/dm-devel
-- 

----------------------------------------------------------------------
    Chandra Seetharaman               | Be careful what you choose....
              - sekharan@us.ibm.com   |      .......you may get it.
----------------------------------------------------------------------

Re: Device-mapper-multipath RDAC

[Nuno Fernandes]

On Monday 24 September 2007 19:33:32 Chandra Seetharaman wrote:
> On Mon, 2007-09-24 at 17:06 +0100, Nuno Fernandes wrote:
> > hello,
> >
> > Just a question:
> >
> > With recent support for rdac hardware handler in kernel 2.6.23-rc7, what
> > configuration should be in storage DS4700? AVT (Automatic Volume
> > transfer) turned on or off?
>
> Hardware handler is needed only for RDAC mode, AVT would work without
> the hardware handler.
>
> The decision to use RDAC or AVT depends on your configuration.
>
> > When it's turned on, luns keep on jumping from controller to controller..
>
> dm-multipath will use the other path (in AVT mode, IOW, jump) only if
> I/O in the current path fails.
Yes, but it keeps on jumping because of the multipathd monitoring of alive 
paths.

I'm was already in the process of using
linux-2.6-md-add-dm-rdac-hardware-handler.patch from 
kernel-2.6.18-36.el5.src.rpm (from RHEL5U1 Beta) to rebuild RHEL5.0 stable 
kernel.. Hope it works..

Best rgds
Nuno Fernandes

>
> > Thanks
> > Nuno Fernandes
> >
> > --
> > dm-devel mailing list
> > dm-devel@redhat.com
> > https://www.redhat.com/mailman/listinfo/dm-devel

Re: Device-mapper-multipath RDAC

[Hannes Reinecke]

Nuno Fernandes wrote:
> hello,
> 
> Just a question:
> 
> With recent support for rdac hardware handler in kernel 2.6.23-rc7, what 
> configuration should be in storage DS4700? AVT (Automatic Volume transfer) 
> turned on or off?
> 
Off. AVT is the acronym for 'Automated Volume Transfer', ie the array tries
to transfer the volumes from one controller to the other automatically.

> When it's turned on, luns keep on jumping from controller to controller..
> 
Indeed. That's to be expected.

As a rule:

- With rdac hardware handler: AVT off
- Without hardware handler: AVT on

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		      zSeries & Storage
hare@suse.de			      +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Markus Rex, HRB 16746 (AG Nürnberg)

Re: Device-mapper-multipath RDAC

[Nuno Fernandes]

[-- Attachment #1.1: Type: text/plain, Size: 971 bytes --]

On Tuesday 25 September 2007 06:54:39 Hannes Reinecke wrote:
> Nuno Fernandes wrote:
> > hello,
> >
> > Just a question:
> >
> > With recent support for rdac hardware handler in kernel 2.6.23-rc7, what
> > configuration should be in storage DS4700? AVT (Automatic Volume
> > transfer) turned on or off?
>
> Off. AVT is the acronym for 'Automated Volume Transfer', ie the array tries
> to transfer the volumes from one controller to the other automatically.
>
> > When it's turned on, luns keep on jumping from controller to controller..
>
> Indeed. That's to be expected.
>
> As a rule:
>
> - With rdac hardware handler: AVT off
I'm in the process of testing avt in the kernel.

> - Without hardware handler: AVT on
With this situation i don't have any point of failure but the lun keeps on 
jumping (because of the alive path check of multipathd) and the performance 
is awfull.

Best regards
Nuno Fernandes

>
> Cheers,
>
> Hannes



[-- Attachment #1.2: This is a digitally signed message part. --]
[-- Type: application/pgp-signature, Size: 189 bytes --]

[-- Attachment #2: Type: text/plain, Size: 0 bytes --]

Re: Device-mapper-multipath RDAC

[Chandra Seetharaman]

On Tue, 2007-09-25 at 08:52 +0100, Nuno Fernandes wrote:
> On Tuesday 25 September 2007 06:54:39 Hannes Reinecke wrote:
> > Nuno Fernandes wrote:
> > > hello,
> > >
> > > Just a question:
> > >
> > > With recent support for rdac hardware handler in kernel 2.6.23-rc7, what
> > > configuration should be in storage DS4700? AVT (Automatic Volume
> > > transfer) turned on or off?
> >
> > Off. AVT is the acronym for 'Automated Volume Transfer', ie the array tries
> > to transfer the volumes from one controller to the other automatically.
> >
> > > When it's turned on, luns keep on jumping from controller to controller..
> >
> > Indeed. That's to be expected.
> >
> > As a rule:
> >
> > - With rdac hardware handler: AVT off
> I'm in the process of testing avt in the kernel.
> 
> > - Without hardware handler: AVT on
> With this situation i don't have any point of failure but the lun keeps on 
> jumping (because of the alive path check of multipathd) and the performance 
> is awfull.

Hmm... Did you have the configuration entries in multipath.conf (same as
that of the RDAC case - with the exception of the hardware handler) ?
> 
> Best regards
> Nuno Fernandes
> 
> >
> > Cheers,
> >
> > Hannes
> 
> 
> --
> dm-devel mailing list
> dm-devel@redhat.com
> https://www.redhat.com/mailman/listinfo/dm-devel
-- 

----------------------------------------------------------------------
    Chandra Seetharaman               | Be careful what you choose....
              - sekharan@us.ibm.com   |      .......you may get it.
----------------------------------------------------------------------

Multipath-tools not seeing replaced RAID controller

[S. J. van Harmelen]

Hi Chandra,

I hope you can answer this question, but of course I'll be very happy if
anyone on this list can answer my question.

I just replaced a faulty RAID controller in an MD3000 enclosure. Now
after enabling it, I can't see it in the multipath driver (mutlipath
-ll). Not even after restarting the multipath-tools (version 0.4.8)...

So what should I restart so that it sees the new controller? I rather
not restart the host if possible...

Thanks!!

Sander

Re: Multipath-tools not seeing replaced RAID controller

[Chandra Seetharaman]

On Wed, 2008-02-13 at 23:09 +0100, S. J. van Harmelen wrote:
> Hi Chandra,
> 
> I hope you can answer this question, but of course I'll be very happy if
> anyone on this list can answer my question.
> 
> I just replaced a faulty RAID controller in an MD3000 enclosure. Now
> after enabling it, I can't see it in the multipath driver (mutlipath
> -ll). Not even after restarting the multipath-tools (version 0.4.8)...
> 
> So what should I restart so that it sees the new controller? I rather
> not restart the host if possible...
> 

Do you see the disks ? (doing a lsscsi would show it). I guess not.

If not, you need to probe/hotplug the disks first

ho,
# echo "- - -" > /sys/class/scsi_host/host${host_no}/scan
  ## the three -'s are for wildcards for channel, id and LUN.

If you don't know the "host_no", do it on for all the hosts under
scsi_host, it will not harm anything.

If you have multipathd running when you run the "echo" above you would
see all the dm devices when it completes (or soon thereafter).

You don't need to reboot the server.

> Thanks!!
> 
> Sander
> 
-- 

----------------------------------------------------------------------
    Chandra Seetharaman               | Be careful what you choose....
              - sekharan@us.ibm.com   |      .......you may get it.
----------------------------------------------------------------------

Re: Multipath-tools not seeing replaced RAID controller

[S. J. van Harmelen]

Hi Chandra,

Your absolutely the best :) It works like a charm!! Thanks a lot...

Sander


On Wed, 2008-02-13 at 17:30 -0800, Chandra Seetharaman wrote:
> On Wed, 2008-02-13 at 23:09 +0100, S. J. van Harmelen wrote:
> > Hi Chandra,
> > 
> > I hope you can answer this question, but of course I'll be very happy if
> > anyone on this list can answer my question.
> > 
> > I just replaced a faulty RAID controller in an MD3000 enclosure. Now
> > after enabling it, I can't see it in the multipath driver (mutlipath
> > -ll). Not even after restarting the multipath-tools (version 0.4.8)...
> > 
> > So what should I restart so that it sees the new controller? I rather
> > not restart the host if possible...
> > 
> 
> Do you see the disks ? (doing a lsscsi would show it). I guess not.
> 
> If not, you need to probe/hotplug the disks first
> 
> ho,
> # echo "- - -" > /sys/class/scsi_host/host${host_no}/scan
>   ## the three -'s are for wildcards for channel, id and LUN.
> 
> If you don't know the "host_no", do it on for all the hosts under
> scsi_host, it will not harm anything.
> 
> If you have multipathd running when you run the "echo" above you would
> see all the dm devices when it completes (or soon thereafter).
> 
> You don't need to reboot the server.
> 
> > Thanks!!
> > 
> > Sander
> > 

Re: Device-mapper-multipath RDAC

[Nuno Fernandes]

On Tuesday 25 September 2007 06:54:39 Hannes Reinecke wrote:
> Nuno Fernandes wrote:
> > hello,
> >
> > Just a question:
> >
> > With recent support for rdac hardware handler in kernel 2.6.23-rc7, what
> > configuration should be in storage DS4700? AVT (Automatic Volume
> > transfer) turned on or off?
>
> Off. AVT is the acronym for 'Automated Volume Transfer', ie the array tries
> to transfer the volumes from one controller to the other automatically.
>
> > When it's turned on, luns keep on jumping from controller to controller..
>
> Indeed. That's to be expected.
>
> As a rule:
>
> - With rdac hardware handler: AVT off
I'm in the process of testing avt in the kernel.

> - Without hardware handler: AVT on
With this situation i don't have any point of failure but the lun keeps on 
jumping (because of the alive path check of multipathd) and the performance 
is awfull.

Best regards
Nuno Fernandes

>
> Cheers,
>
> Hannes

Re: Device-mapper-multipath RDAC [SOLVED]

[Nuno Fernandes]

On Tuesday 25 September 2007 06:54:39 Hannes Reinecke wrote:
> Nuno Fernandes wrote:
> > hello,
> >
> > Just a question:
> >
> > With recent support for rdac hardware handler in kernel 2.6.23-rc7, what
> > configuration should be in storage DS4700? AVT (Automatic Volume
> > transfer) turned on or off?
>
> Off. AVT is the acronym for 'Automated Volume Transfer', ie the array tries
> to transfer the volumes from one controller to the other automatically.
>
> > When it's turned on, luns keep on jumping from controller to controller..
>
> Indeed. That's to be expected.
>
> As a rule:
>
> - With rdac hardware handler: AVT off
Working..

Thanks
Nuno Fernandes
> - Without hardware handler: AVT on
>
> Cheers,
>
> Hannes