HP 3PAR InForm OS 2.3.1 Extended MU5 Release Notes (QL226-96621, May 2013)

Downgrade Issues
The following are downgrade issues for all versions of InForm OS 2.3.1.
Issues Preventing Downgrades
These issues will prevent a storage system from downgrading from all versions of InForm OS 2.3.1 to
InForm OS 2.2.4. (These issues do not apply to a downgrade from 2.3.1 MU2 to 2.3.1.)
• Dual SD Space - Thin Provisioned virtual volumes can have two Snap Data (SD) volumes in 2.3.1
and 2.3.1 MU2. This is not a supported feature in previous InForm releases. Prior to a downgrade,
dual SD TPVVs must be converted to single SD TPVVs by removing all of the snapshots for those
TPVVs.
• RAID Multi-Parity (MP) - RAID MP (RAID 6) was not supported in InForm OS releases prior to
2.3.1, therefore any RAID MP Logical Disks (LDs) must be tuned to a supported RAID type or
removed prior to downgrade.
• SD Reclaim Space - SD Reclamation is not supported by InForm OS releases prior to 2.3.1. Before
a downgrade, SD volumes that have its space reclaimed must be removed. If that SD is used by
snapshots only, then all of its snapshots must be deleted so that SD can be freed. If that SD space
is used by the TPVV itself, then that TPVV would need to be copied over to a new single SD TPVV.
After the copy operation completed, the original TPVV can be removed.
• 256 Read/Write Snapshots - In InForm OS 2.3.1 and 2.3.1 MU2, the number of read/write
snapshots was increased to 256 per virtual volume. Previous release supported a smaller maximum
number of read/write snapshots per virtual volume. A downgrade will be prevented if any virtual
volume has more read/write snapshots than the maximum supported on the previous release.
When enough snapshots have been removed to meet this criterion the downgrade is allowed.
• Multiple Read/Write Snapshots per Read-Only Snapshot - In InForm OS 2.3.1 and 2.3.1 MU2,
the creation of multiple read/write snapshots per read-only snapshot is permitted. Previous releases
supported a single read/write snapshot per read-only snapshot. A downgrade will be prevented
if any read-only snapshot has more than one read/write snapshot. Once enough read/write
snapshots have been removed to meet this criteria, the downgrade is allowed.
• Synchronous Long Distance Remote Copy - If there are Remote Copy groups configured with
multiple targets, those groups must be removed or reduced to a single target before a downgrade
is allowed.
• 16 TB Support - Virtual volumes larger than the maximum size supported in a previous release
must be removed before a downgrade is allowed.
• Multiple Remote Copy Links per Node - InForm OS release 2.3.1 and 2.3.1 MU2 allow multiple
Remote Copy links to be configured on a individual node. Previous releases only allowed a single
link per node. Before downgrading, ensure that additional Remote Copy links are dismissed to
ensure a valid configuration for the downgrade. A check is run prior to downgrade to validate
the existing Remote Copy link configuration.
10 HP 3PAR InForm Operating System Release Notes