Veritas DMP and EMC PowerPath on the same server.

[Abimbola_Adegun]

Hi,

We have a system with EMC AX-45 array with EMC PowerPath. Now we need to extend with a Hitachi VSP SAN which is not supported in PowerPath.

Is it possible to use EMC PowerPath for the EMC storage and VxDMP for the Hitachi SAN?

Thanks in advance.

Best Regards,

Abimbola

[mikebounds]

Why do you want to use 2 different disk multipathing solutions on the same host - why not use DMP for both - this is one of the advantages of DMP, that you can use it with any array.

Mike

[Abimbola_Adegun]

I am concerned about any other dependencies on the existing applications. Please explain the risks associated with co-existing 2 disk multipathing solutions.

Abimbola

[gseibak]

you should be able to. You will just need to exclude the EMC devices from Veritas so it does not try to handle them.

[Leed_Engineer]

Yes you can do this , however , you will need to exclude the controllers that are connected to EMC storage from DMP control .

Add the controller in the file /etc/vx/vxdmp.exclude 

then make sure it is excluded by running #vxdmpadm listexclude

then rerun vxdctl enable

[bazi]

Abimbola,

Have you tried runnning powermt unamange againt the Hitachi class?

powermt unmanage class=hitachi

This should exclude HDS devices from being taken under controll of Power Path. As a result there should be no emcpowerX devices. VxDMP should then no longer for in TPD mode for HDS storage and shoule take over multipathing controll.

Leave EMC class managed so that VxDMP continues working in TPD mode for the EMC disks.

Thanks

Wojtek

[joseph_dangelo · Accepted solution]

Abimbola,

The inherent risk to using more than one Multipath solution is the unnecessary complexities associated with the management of the paths and storage resources,  VxDMP is fully supported on EMC and HDS arrays and will provide a number of advantages over that of PowerPath.  Most importantly will be in the representation of the devices themselves.  PowerPath uses path suppression and thus creates virtual disk devices that are labeled as emcpower###.  VxDMP does not suppress paths, however with our enclosure based naming scheme, you can reference the devices by names such as emc_vmax01_### or usp01_### where the last characters are the LUN Serial number as defined by the Array.  By using 2 multipath devices you will actually have to refer to the EMC luns and HDS luns in a completely different fashion. 

This can cause a lot of confusion when dealing with disk groups and volumes that span both arrays. Our vxdisk command hoiwever will list only a single device per Lun/Path grouping and therefore will ensure that the correct devices are chosen when creating new volumes.

Hope this helps.

Joe D 

[switchtech]

DMP and PowerPath can coexist on the same system managing different arrays. You can use DMP for the Hitachi, and PowerPath for the EMC array. If you plan to use the PowerPath devices in Volume Manager(create volumes with them) then you should not exclude the devices.

Regards,

Rich