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Checkdisk on VA7400 BC LUNs

Patrick Greuter
Occasional Visitor

Checkdisk on VA7400 BC LUNs

Hello,

during the startup phase my W2k Backup Server (W2K Server SP2) performs a checkdisk on the BC LUNs (VA7400 HP16). The Security for the backup server is permanently enabled. After the Data has been written to the Tape Library the BC LUNs will be dismounted. This strategie works fine but if a server restart is required a checkdisk will be performed.
Are there any effects to the BC LUNs after chkdsk ?
Or is that a known problem and there are no effects ?

Kind regards

Patrick Greuter
3 REPLIES
Vincent Fleming
Honored Contributor

Re: Checkdisk on VA7400 BC LUNs

Hi Patrick! Welcome to the forums!

Changes made to BCs are not written to the parent LUNs, so chkdsk will not harm your production data.

If your backup software is operating properly, it should be putting the parent LUN into a steady state (quiesse the database for example) before snapping the BC. This will ensure that chkdsk doesn't invalidate your backup.

Good luck!

No matter where you go, there you are.
Patrick Greuter
Occasional Visitor

Re: Checkdisk on VA7400 BC LUNs

Hi Vincent,

thanx for your answer. The most important thing is to know, if a chkdsk on the BC LUNs will damage any data, and if the BC LUNs can be recovered to the parent LUNs with a valid state.

Furthermore is there a possibility to prevent this chkdsk at startup procedure ?

Why is there a chkdsk at the server startup procedure ?

Thanx

Patrick
Vincent Fleming
Honored Contributor

Re: Checkdisk on VA7400 BC LUNs

Filesystems have a bit on them that is flipped when the filesystem is either mounted or unmounted. If the host system comes up and sees a filesystem on a LUN that has it's bit set to "mounted" already, it checks it before mounting it - it's an indication of a system crash.

In your case, the BC is snapped from a mounted filesystem, so the bit is set in the BC. Normally, chkdsk will not need to "fix" anything (since there was no system crash) and just resets the bit. Again, modifying the BC will NOT modify the parent LUN. Also, if your backup software is operating properly, it will make sure there's nothing wrong with the FS structure when the BC is created.

Good luck!
No matter where you go, there you are.