Performing an NSS poolrebuild, poolverify or nssscan without deactivating the pool

NSS Pools must be deactivated and put in to maintenance mode to run a pool verify, pool rebuild or nssscan.

How can these tools be run whilst the NSS pool remains accessible to users?

How long will a pool rebuild take to run?

Novell Support have requested an nssscan but this will take the pool offline disrupting service.

Take an NSS snapshot of the pool and run the relevant tool against the snapshot.

Important:  See Additional Information, below.

A summary of the procedure is as follows (assuming a pool named DATAPOOL and a snapshot named DATAPOOLSNAP):

• nssmu
  -> Snapshot
  -> <INS>
  -> <DATAPOOLSNAP>
  -> <Select DATAPOOL>
  -> <Select sufficient free space>
• Once created, mount the snapshot with <F7> and exit nssmu
• nsscon
  -> /poolmaintenance=datapoolsnap
  -> exit
  

Run the appropriate tool against the snapshot

• ravsui rebuild datapoolsnap
• ravsui verify datapoolsnap
• OES2: nssscan save DATAPOOLSNAP /dev/evms/DATAPOOLSNAP
• OES11: nssscan save DATAPOOLSNAP /dev/pool/DATAPOOLSNAP

This is only a quickstart summary.  For complete instructions on how to manage NSS Snapshots, refer the section Managing NSS Pool Snapshots in NSS File System Administration Guide for Linux available at https://www.novell.com/documentation

Important

NSS Snapshots cannot be used on shared (clustered) pools.

Pool Rebuild

• It is possible to run a rebuild on a snapshot, but what is actually being rebuilt is the snapshot pool, not the real pool.  The real pool is not changed at all.  The only things this will accomplish is to verify that a rebuild can be successfully run, an indication of how long it will take and some indications of the outcome from the resulting log files.  In order for the changes to happen on the real pool, the real pool must be rebuilt.

NSS Scan

• In most cases an nssscan can be run against a snapshot.  However, there may be a few blocks that will be different in the snapshot that will not be in the real pool, but most will be the same.  An example may be the superblocks.  If Novell Support has requested an nssscan check first whether such a scan taken against a snapshot will be sufficient.