Data Integrity Validation and Splitting Mirrors

Data Integrity Validation and Splitting Mirrors
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Recovery from Data Integrity Loss
Any inconsistencies reported by FCHECK -SCAN require special handling to determine
the correct course of action to properly recover the data set. As a general rule, an
FCHECK without the –SCAN option should be performed if the reported file or table is
structured.
The first step is to identify if one of the disks in the mirrored pair is defective or contains
all the inconsistencies. If this can be determined, the defective or inconsistent drive
should be the target of a revive operation to correct the inconsistencies.
WARNING: If there is any doubt as to the location of the inconsistent or
mismatched data, contact your HP support representative for assistance. Removing
the wrong drive from service, or removing either drive from service when both
contain inconsistencies, may result in an inability to recover the suspect data.
If the file or table cannot be otherwise recovered via standard data recovery mechanisms
such as RESTORE or TMF RECOVER FILES, contact your HP support representative
for assistance.
FCHECK -SCAN Instructions
The FCHECK -SCAN operation for data validation associated with splitting mirrors is
performed by running the FCHECK process:
FCHECK [/ PRI nnn /] –SCAN [-RATE <nnn>] –VOL <$volume>
-SUBVOL <subvol>
-FILE <filename>
Every file and table on the volume will be scanned when the –VOL option is specified.
The user can specify –FILE for a specific file or –SUBVOL for the set of files contained
within a sub-volume.
A priority should be specified to avoid impact to production activity. The specified
priority should be less than the priority of the production workload, and should also be
less than 151.
The –RATE option should also be considered for environments when production
response time increases cannot be tolerated. The default rate is 100. It can be reduced to
a value between 1 and 99. The lower the rate, the smaller the impact will be to
production activity.
A reduced RATE and a reduced PRIORITY will not typically slow the pace of the scrub
when there is no concurrent activity.