Veritas DMP Vs EMC Power path

[victvishwa]

Hi,

I m a new bie to Storage Foundataion and High Availability.

We are configuring SFHA 5.1 SP1 in our setup with EMC Clarion as the storage, and would like to know the below

1. Can VxDMP and EMC Power path co-exist on the same server?

2. What should be set as the vxfenmode in /etc/vxfenmode for scsi3_disk_policy=? when EMC Power is used? Should it be used as dmp or raw?

3. When raw devices are used, how the situations like Split brain are handled?

Since we used as scsi3_disk_policy=dmp, the I/O fencing did not work, error stating V-16-1-10031 VxFEN drivers not configured, stopping VCS, Manually start VCS once the I/O fencing is configured.

Have also configured UseFence = SCSI3

Thanks

Kasi VPS

[joseph_dangelo · Accepted solution]

Kasi,

While yes you can coexist DMP with PowerPath, I would recommend against any configuration that uses more than one DMP software. Obviously I am partial to DMP in this case, but as matter of unnecessary complexity I would stick with a single solution.

VxDMP fully supports the Clariion array family and as it would appear you are using CFS, I would recommend using DMP outright for all devices. You can save on the cost of PowerPath for these particular host :o)

In terms of fencing with PowerPath devices, I recently came across a similar scenario where a customer was inquiring about the same support. I will have to follow-up to provide you a sufficient answer.

To answer you question about fencing and the use of RAW devices, it is fully supported as the SCSI-3 Reservations are not associated with a File System or Volume but rather the underlying disk device. During a network partition/split brain, the coordinator race for control of the disks will eject or fence the losing node that is no longer communicating over GAB/LLT

Hope this was helpful.

Joe D