VCS 5.0 MP4 on RHEL 5.5 64bit

[enzo68]

Hi to all,

we have installed vcs 5.0 MP4 on 5.5 64bit.

The storage is an IBM DS3000. We have RDAC as multipaths  controller, so we have only a device path for any lun ( sdX, sdY, etc ).

We would like to use LVM so we would know if there are problem to use VCS 5.0MP4 with LVM and IBM RDAC.

Thanks in advance,

Vincenzo

[mikebounds]

VCS support LVM as it provides LVM agents and if you are using LVM rather than Veritas Volume Manager then it doesn't matter what disk multipathing you use.

Mike

[mikebounds]

Appologies - information in last post is wrong as I was thinking this was LVM on AIX (which does NOT use a DiskReservation agent) and just realised this is LVM on Linux.  According to the Linux VCS Bundled agents guide:

You cannot use the DiskReservation agent to reserve disks that have multiple

paths. The LVMVolumeGroup and the LVMLogicalVolume agents can only be

used with the DiskReservation agent, Symantec does not support the

configuration of logical volumes on disks that have multiple paths. To ensure

data protection on such a configuration, Symantec recommends the use of

Veritas Volume Manager (VxVM) disk groups

This is not that clear because when you look at dependency diagram for LVMLogicalVolume agent it does not show the DiskReservation resource, but it does show the DiskReservation resource in the  dependency diagram for the LVMVolumeGroup agent and it is the DiskReservation agent that does not support disk multipathing as oppose to LVM agents

The IBM DS3000 is supported by Volume Manager so you could use VxVM.

However it may depend on what level the multipathing is at.  I don't know much about RHEL LVM, but if LVM can provide disk multipathing, then this could be what is not supported, so if the disk multipathing is at a lower level so the device sdX represents 2 paths, then if you use this path with the DiskReservation agent this MAY be ok  - someone from Symantec would need to clarify this.

Mike

[enzo68]

Hi,

thanks for your response.

We said that because we have found a note in this link "http://www.symantec.com/business/support/index?page=content&id=TECH146404".

It seems that "Configuration of Linux RHEL5 LVM and native Multi-pathing is not supported by VCS."

So the our doubt is that there could be some problem with RDAC multipath too.

Best regards,

Vincenzo

[mikebounds · Accepted solution]

http://www.symantec.com/business/support/index?page=content&id=TECH146404 says:

Configuration of Linux RHEL5 LVM and native Multi-pathing is not supported by VCS.

and

If SAN LUN multipathing is a requirement for the VCS cluster, the recommedation is to migrate LVM data to  VxVM 5.1 with its bundled DMP multipathing or use other VxVM compatible third party (TPD)  multipathing software (e.g. EMC PowerPath).

But I cannot find a list of "compatible third party (TPD) multipathing software" that is supported.

Looking at the HCL (http://www.symantec.com/business/support/index?page=content&id=TECH47620) this has the information for AIX, but I can't find for Linux.  So for AIX the HCL says

The VCS LVM agent supports the EMC PowerPath third-party driver on EMC's Symmetrix 8000 and DMX series arrays.

The VCS LVM agent supports the IBM MPIO third-party driver on IBM's DS8000 arrays.

The VCS LVM agent supports the IBM SDD third-party driver on IBM's ESS750/800 and DS8000 arrays.

The VCS LVM agent supports the HITACHI HDLM third-party driver on Hitachi USP/NSC/USPV/USPVM, 9900V series arrays.

I would contact Symantec support and ask where this information is for Linux.

Mike

[enzo68]

Hi Mike,

thanks for reply,we 'll install VCS 5.1 SP1 with VXVM.The last question is about multipath.In fact is present the RDAC(IBM) multipath and we would disable the VXVM dmp because RDAC is a must.

What do you think about it?The RDAC is low level dmp that operate under linuix devices sd#.

Regard

Vincent

[mikebounds]

I looked at information for 5.0 first as I didn't noticed you had changed to mentioning 5.1, so relevent info for 5.0 is:

You need ASL: http://www.symantec.com/business/support/index?page=content&id=TECH125246

DMP/RDAC info: http://www.symantec.com/business/support/index?page=content&id=TECH47728

For 5.1, the DS3000 is listed on HCL so supported with VxVM and http://www.symantec.com/business/support/index?page=content&id=TECH51507 gives "Guidelines on using OS Native Multi-pathing with DMP", but it does not mention RDAC.

Mike