Breaking hardware disk mirror to duplicate a system

Mansell, Gary GRMansell at ricardo.com
Mon Mar 17 11:43:00 CST 2003


As a means of protection, I would periodically like to break the mirror of my server and place it into an identical spare machine that I have as a "cold spare". I currently have a 2 PE2650's with identical mirrored system disks.

This is the procedure that I envisage, please can someone confirm whether this is safe to do:

1) On the "cold spare" machine, at the Adaptec BIOS level, initialise both disks then remove them.
2) Pull the second drive from my production machine whist the machine is running.
3) Put the drive from 2) into my spare machine and boot from it.
4) put the two spare disks from 1) into each machine and wait for them to re-sync.

Some questions come to mind:

1) Is this OK to do or are there command line tools that I should use to offline a disk before pulling it from a live running system? If so how do I do this?
2) I am presuming that initialising the disks (step 1) will ensure that the machine synchronises in the correct manner - ie, the machine will not try and mirror the initialised disk over the live system disk?
3) When the machine has rebuilt the degraded mirror, is the machine safe again or is there any settings that I need to change to tell the server that it is OK again. Do i need to reboot the server etc?

Thanks in advance for any help

Gary Mansell
Senior Technical Analyst
IT Department
Ricardo Consulting Engineers Ltd




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