Breaking RAID5 to RAID1-- How?

[Sailesh Pokal]

Hi,
We have RAID5 (Model20) diskarray, but we want to break it to RAID1. Is it
possible -- Is there any documentation or site where I can get any information.
Has anyone undergone this -- .What steps and precaution needs to be taken to
achieve this.

Thanks.
Sailesh.

[Mike Seerden_3]

Sorry, but there is no way to migrate from RAID5 to RAID1. The only thing you
can do is backup the data, create your RAID1 sets and restore the data.

[Sailesh Patel]

The question pertains to the hardware configuration and not to data restore.
Breaking of RAID5 and configuring it back to RAID1. What software tools are
required to accomplish this.

[Shyam Kishore]

You can very well do that, if data is not the major problem.

You can use the console port of the model20 BOX and configure as you require.

or

You can even configure the same Box with SAM if you are using 10.00 or later.

-Shyam

[Emmanuel Eyer]

I would prefer using GridManager (the one guy you connect to thru the serial port of your model 20).

First unmount the filesystems and stop swapping on the RAID 5 PVs (may need to reboot). Deactivate the VG. Export the VG (or do the whole fuss to vgremove).

Now connect to GridManager (or use SAM, assuming proper patches and drivers). Unbind the RAID-5 LUN. Now it's too late for your data...

Then, still thru GridManager (or SAM), bind new RAID-1 LUNs (take care about the various options, especially caching wich is disabled by default). Notice the LUN numbers (must be below 7). Wait for binding to be done (can be pretty long, one hour or more); you can check this in GridManager Presentation Utility.

Once done, get back to your HP/9000. If you can reboot it, do it. If not, do an ioscan -fCdisk (do NOT use the -k flag). It may be a bit long (a couple of minutes). Don't worry about the NO_HW devices, if any (they will disappear on next reboot). Notice the disk devices for your new LUNs. Then run insf -eCdisk -Ix, where x is the instance# of your disk devices. This will create the device files - without rebooting.

Finally, you can pvcreate, and do all remaining LVM activity to integrate the new LUNs.

All this should run smoothly. I did it dozens of times without any problem. Just ensure you have enough time, and your data are in a safe place ;-)

[Charles Akonnor]

What you want to do is achievable, but this is option is not cost effected since only 1/2 of the total disk space will be available to you.Raid 1 is mirrorring.

1. back up everything on the disk array
2. remove all the filesystems and logical volumes on the disk array.
3. Unbind all the raid 5 LUNs created on the disk array.
4. Rebind the disks selecting and even number of disks at a time and binding with raid level of 1.
5. recreate your logical volumes and filesystems considering the name and sizes of the filesystems before the start of the proceedure.
6. Restore all your data back and you should be there.

Note that you will have less disk space after RAID 1 than with RAID 5.
Also test your backup before you delete any infomation