Restrictions On Database Validator - Hitachi VSP F1500 User And Reference Manual

• Data block address corruption: The OS (file system, LVM, Disk driver)
might write blocks to the wrong location. The RAID storage system can
check the validity of the data block address to verify that the Oracle data
block is written to the correct location on disk.
• Protection of Oracle volume: Oracle data files might be overwritten by a
non-Oracle application or by human operation using a command. The
RAID storage system can protect volumes storing Oracle files by
preventing the volumes from being modified by another application or by
human error.

Restrictions on Database Validator

• Oracle® tablespace location
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• Restoring Oracle® files
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Old blocks can exist on disk without checksum information in them if the
database was running without checksum enabled in the past.
• Oracle® on LVM(VxVM)
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7-4
File system-based Oracle files are not supported by Database
Validator. All Oracle database files must be placed on raw volumes
(including LVM raw volumes) directly.
If host-based striping is used on raw volumes, then the stripe size
must be an exact multiple of the Oracle block size.
Oracle redo log files (including archive logs) must be on separate
volumes with respect to the data files (including control files). In other
words, Oracle redo log files and the data files must not be mixed on
the same LU.
Before restoring Oracle data files from a backup, data validation might
need to be temporarily turned off for those data files that were backed
up prior to the Oracle checksum being enabled.
LVM block size must be a multiple of the Oracle block size. The Oracle
block size must be less than or equal to the minimum of the LVM
stripe size and the largest block size at which LVM will not fracture
(known as "Logical Track Group" in LVM), which is 256 KB in LVM.
When adding new physical volumes (PVs) to a logical volume (LV) to
be used as an Oracle data file, control file, or online log, the data
validation should be re-enabled in order to have HARD checking take
effect on those new PVs.
Similarly, in order to have HARD checking no longer performed on PVs
that have been removed from an LV that had previously been used by
Oracle, HARD checking should be explicitly disabled on the device
corresponding to the PV.
If host-based mirroring is used such as LVM mirroring, all component
PV mirrors must be HARD-enabled, otherwise the entire logical
volume (LV) is exposed. That is, if a user takes an unmirrored HARD-
enabled LV, then makes it mirrored on the fly without HARD-enabling
all sides of the mirror, that entire LV is exposed to data corruption.
Data protection operations with CCI
Command Control Interface User and Reference Guide