/dev/dm-N and Veritas?

/dev/dm-N and Veritas?

[Bruen, Mark]

Anyone using Veritas to manage their /dev/dm-N devices?
Thanks.
    -Mark

Re: /dev/dm-N and Veritas?

[Christophe Varoqui]

On lun, 2005-10-31 at 14:27 -0500, Bruen, Mark wrote:
> Anyone using Veritas to manage their /dev/dm-N devices?
> Thanks.

I guess few people can understand what you mean.
For one, I can't, sorry.

Regards,
cvaroqui

Re: /dev/dm-N and Veritas?

[Bruen, Mark]

I would like to use "device mapper" for multipathing which I have setup 
and Veritas Volume Manager for Virtualization. I normally  create LUNs 
on the SAN and they show up as /dev/sdX, /dev/sdY, etc... I initialize 
them for use with Veritas Volume Manager which allows me to expand 
filesystems across multiple LUNs, create snapshots, split disks off for 
deporting, etc...
I have many years of Veritas experience and none with LVM so I would 
(for now anyway) like to use the multipathed devices /dev/dm-N with 
Veritas. Is it possible?
Thanks.
    -Mark

Christophe Varoqui wrote:

>On lun, 2005-10-31 at 14:27 -0500, Bruen, Mark wrote:
>  
>
>>Anyone using Veritas to manage their /dev/dm-N devices?
>>Thanks.
>>    
>>
>
>I guess few people can understand what you mean.
>For one, I can't, sorry.
>
>Regards,
>cvaroqui
>
>
>
>--
>dm-devel mailing list
>dm-devel@redhat.com
>https://www.redhat.com/mailman/listinfo/dm-devel
>  
>

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Re: /dev/dm-N and Veritas?

[Greg Freemyer]

Veritas has a commercial LVM product.  I assume the question was about
using it to manage device mapper devices.

On 10/31/05, Christophe Varoqui <christophe.varoqui@free.fr> wrote:
> On lun, 2005-10-31 at 14:27 -0500, Bruen, Mark wrote:
> > Anyone using Veritas to manage their /dev/dm-N devices?
> > Thanks.
>
> I guess few people can understand what you mean.
> For one, I can't, sorry.
>
> Regards,
> cvaroqui
>
>
>
> --
> dm-devel mailing list
> dm-devel@redhat.com
> https://www.redhat.com/mailman/listinfo/dm-devel
>


--
Greg Freemyer
The Norcross Group
Forensics for the 21st Century

Re: /dev/dm-N and Veritas?

[Christophe Varoqui]

On lun, 2005-10-31 at 15:04 -0500, Bruen, Mark wrote:
> I would like to use "device mapper" for multipathing which I have setup 
> and Veritas Volume Manager for Virtualization. I normally  create LUNs 
> on the SAN and they show up as /dev/sdX, /dev/sdY, etc... I initialize 
> them for use with Veritas Volume Manager which allows me to expand 
> filesystems across multiple LUNs, create snapshots, split disks off for 
> deporting, etc...
> I have many years of Veritas experience and none with LVM so I would 
> (for now anyway) like to use the multipathed devices /dev/dm-N with 
> Veritas. Is it possible?
> Thanks.
>     -Mark
> 
There are some issues in this field : /dev/dm-* might or might not
exist, might be duplicate of /dev/mapper/ entries, paths appear
as /dev/sd* nodes and are not hidden.

The Volume manager has to deal with these things. Even LVM2 has rough
edges here. I would guess VxVM may have a hard time too.

That said, this question will ultimately have to be responded by
Veritas. I can image them saying that you'd better use *their*
multipathing solution, being well integrated with the volume manager.

The DM multipathing is easily disabled.

Regards,
cvaroqui

Re: /dev/dm-N and Veritas?

[Bernd Zeimetz]

> The Volume manager has to deal with these things. Even LVM2 has rough
> edges here. I would guess VxVM may have a hard time too.

are there any known issues with lvm? Especially together with dm-emc?

Thank you,

Bernd

Re: /dev/dm-N and Veritas?

[Brian Long]

On Mon, 2005-10-31 at 14:27 -0500, Bruen, Mark wrote:
> Anyone using Veritas to manage their /dev/dm-N devices?

Mark,

There is no point in using device-mapper multipathing since Veritas has
their own multi-pathing software built-in.  What would be the point?
Veritas won't support you unless you use DMP (Dynamic Multi Pathing).

If you're going the Veritas route instead of using LVM2, you should use
their stuff solely.

We did an in-house Veritas vs. LVM2 show-down on Linux and LVM2 provides
enough functionality for our needs.  It doesn't provide functionality
for some of our "wants", but we've decided to go with LVM2 as we deploy
RHEL 4.

/Brian/

-- 
       Brian Long                      |         |           |
       IT Data Center Systems          |       .|||.       .|||.
       Cisco Linux Developer           |   ..:|||||||:...:|||||||:..
       Phone: (919) 392-7363           |   C i s c o   S y s t e m s

Re: /dev/dm-N and Veritas?

[Bruen, Mark]

Brian,
    We have a substantial investment in Veritas as well as people who 
know Veritas and multiple platforms to support which all run Veritas. 
There are three reasons driving my device mapper analysis: 1). We've had 
major problems with DMP on EMC Clariion arrays with Linux running 
Veritas Storage Foundation for Oracle Real Application Clusters, I still 
do not have resolution from Symantec (formally Veritas). 2). We use 3PAR 
storage and they say they will not support DMP on RHEL4 but will only be 
supporting DM.  3). I would really like to remove the storage vendor 
dependency on the Array Support Library (ASL) which is required by most 
storage vendors to use DMP. With DM the storage need only to provide the 
LU(s) on multiple paths with the same SCSI serial number. It also allows 
you to have persistent device names when adding or removing LUs and 
rebooting. At some point we may be looking at LVM but not until it can 
perform such functions as point in time snap shots which can be deported 
and then mounted on another host for database replication and other 
functions that we use it for. For consistency which is key to reducing 
labor costs it would also need to run on Solaris,  HPUX and Windows. I'm 
still trying to find a way to use /dev/mapper/<name> devices with Veritas.
Thanks.
    -Mark

Brian Long wrote:

>On Mon, 2005-10-31 at 14:27 -0500, Bruen, Mark wrote:
>  
>
>>Anyone using Veritas to manage their /dev/dm-N devices?
>>    
>>
>
>Mark,
>
>There is no point in using device-mapper multipathing since Veritas has
>their own multi-pathing software built-in.  What would be the point?
>Veritas won't support you unless you use DMP (Dynamic Multi Pathing).
>
>If you're going the Veritas route instead of using LVM2, you should use
>their stuff solely.
>
>We did an in-house Veritas vs. LVM2 show-down on Linux and LVM2 provides
>enough functionality for our needs.  It doesn't provide functionality
>for some of our "wants", but we've decided to go with LVM2 as we deploy
>RHEL 4.
>
>/Brian/
>
>  
>