Break raid 0 on hpux

 
Frank Lomabrdo
Occasional Contributor

Break raid 0 on hpux

hello, I have an hp9000 L class server, it has two 73gb scsi disks in it that are mirrored in raid 0. The OS is stored on a seperate 9gb hard disk. I want to break the raid 0 mirror on the two 73gb disks and just have two 73 gig drives to use, can this be done without destroying the data?

And if so, does anyone have any info on how to do so? We are using Mirror UX on the server.

Thanks
6 REPLIES 6
Michael Steele_2
Honored Contributor

Re: Break raid 0 on hpux

Dear Frank:

RAID 0: Striped Set
RAID 1: Mirrored Set
RAID 5: Striped Set with Distributed Parity
Common nested RAID levels:
RAID 01: A mirror of stripes
RAID 10: A stripe of mirrors
RAID 30: A stripe across dedicated parity RAID systems
RAID 100: A stripe of a stripe of mirrors

If you want to remove a mirror then use the lvextend -m 0 /dev/vg##/lvol# /dev/dsk/c#t#d#' command.
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Frank Lomabrdo
Occasional Contributor

Re: Break raid 0 on hpux

Thank you for the reply, my boss simply said it is 'mirrored' So I am guessing then it is raid 1?

And those commands do not destroy the data?

Patrick Wallek
Honored Contributor

Re: Break raid 0 on hpux

To reduce a mirror from a disk you need to do:

# lvreduce -m 0 /dev/vg??/lvol? /dev/dsk/c?t?d0

Where the /dev/vg??/lvol? is the VG and LVOL as appropriate and /dev/dsk/c?t?d0 is the 73GB disk you want to free.

You must do the lvreduce command for EACH LVOL on the disk.
Patrick Wallek
Honored Contributor

Re: Break raid 0 on hpux

I should add that the lvreduce command will remove the data from the disk you specify, BUT the data will remain on the other 73GB disk.

So your data is relatively safe.

However, if this is a production machine, why would you want to be without a mirror for your data? This is putting your system at great risk for data loss. If the 73GB drive that the data is still on fails, then you are facing a restore of all of your data.

If your OS disk is not mirrored you really should mirror it as well. If that disk were to fail, your entire machine would crash putting everything at risk!
Frank Lomabrdo
Occasional Contributor

Re: Break raid 0 on hpux

Patrick, Thank you for your posts.


This is only a testing/development machine, so it is not mission-critical. The OS is mirrored on two 9gb drives, the data on the 73gb drives is important, just not as important as our production server. It has just company data/programs.

Bill Costigan
Honored Contributor

Re: Break raid 0 on hpux

You may be looking for.

lvsplit â split mirrored LVM logical volume into two logical volumes.

This will keep the data on both sides of the mirror, but splits the mirror and renames one side of the mirror to a differnent lvol name.