Limitations with SF on VMGuests


Limitations with SF on VMGuests
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The Cross Platform Data Sharing (CDS) feature is enabled by default. The HP VMGuest does not support CDS. This restriction renders some of the CDS related features unusable. The CDS feature relies on SCSI mode sense data from the backend disk. HP IVM virtualizes the backend devices. As a result, the actual mode sense data is not available in the VMGuest. To create a VxVM disk group in the IVM environment, disable the CDS feature before creating a new diskgroup. To disable CDS, edit the /etc/default/vxdg file, and set the attribute-value pair cds=off. Alternatively, you can use the following command to set this attribute for a disk group:
```
# vxdg -g diskgroup set cds=on|off
				
```
Note:

To migrate from a non-HP IVM environment to an HP IVM environment using CDS disk groups, migrate all the CDS disk groups to non-CDS disk groups. This migration involves data movement.
The VMGuest does not support the Enclosure Based Naming scheme (EBN) feature. As a result, some features like the following are not supported:
- Enclosure information is not available in the VMGuest. Therefore, all LUNs are claimed under the DISKS category.
- Mirroring across enclosures is also not supported.
SCSI-3 PGR-based I/O Fencing is not supported in the VMGuest. CFS is only supported when fencing is disabled. HP IVM does not support SCSI-3 PGR in the VMGuest for virtualized disks. However, Non-SCSI-3 Fencing with CP Server is supported.

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