VERITAS Storage Foundation 4.1 Cross-Platform Data Sharing Administrator's Guide

Chapter 2, Setting up Your System

Converting a Non-CDS Disk Group to a CDS Disk Group

Use the CDS conversion utility (vxcdsconvert) to make a VxVM non-CDS disk group (DG)

portable between different operating systems that are running versions of VxVM with the CDS

feature. This allows existing data to be made shareable in a CDS environment.

# vxcdsconvert -g diskgroup [-A] [-d defaults_file] \

[-o novolstop] alignment [attribute=value] ...

# vxcdsconvert -g diskgroup [-A] [-d defaults_file] \

[-o novolstop] group [attribute=value] ...

CDS provides the alignment and group keywords for disk group conversion:

◆ Use the alignment keyword to specify alignment conversion. In this case, disks are not

converted, and an object relayout is performed on the disk group. A successful completion

results in an 8K-aligned disk group. You might consider this option, rather than converting the

entire disk group, if you want to reduce the amount of work to be done for a later full

conversion to CDS disk group.

◆ Use the group keyword to specify group conversion. This implies alldisk, and will

perform that function prior to object relayout. All the non-CDS disks in the disk group are

converted.

In addition, you can use the -o novolstop option to perform the conversion on-line (that is,

while use of the disk group continues). However, for a group conversion, this may greatly increase

the amount of time (and work) required for conversion.

Alternatively, stop the application, and perform the conversion off-line. This requires minimal

offline time.

Note the following:

◆ The disk group must be in pristine condition. That is:

◆ It has no dissociated or disabled objects.

◆ No sparse plexes are present.

◆ There are no volumes requiring recovery or having pending snapshot operations.

◆ There are no objects in an error state.

◆ Stopped (but startable) volumes will be started, for the duration of the conversion only.

◆ Conversion has the following side effects:

◆ Any objects created with layout=diskalign can no longer be disk aligned.

◆ Encapsulated disks may lose the ability to be unencapsulated.

◆ Fine performance tuning may be lost as data may have migrated (and even migrated to

different disks).