Replace Mirror Drive on 2104-DU3

[ctoman]

I have a RAID 1 SCSI Array and a drive failed. Do I have to break the mirrors or can I just pull out the failed drive and insert the new drive in? What steps are needed to replace the failed drive? The drive is on a 2104-DU3 Expandable Storage Unit
thanks in advance!
AIX 4.3.3

 

[CrystalWizard]

raid 1 is just regular mirroring. if the drive failed, yeah, you best break the mirror. expect to have to restore when you're finished replacing the drive too.

also, before you pull the hardware, rmdev the failed drive from the aix odm.

why are you using raid 1 instead of doing lvm mirroring? it's a lot more reliable.

 

[ctoman]

Raid1 is hardware mirroring and i believe its the way to go , I did not have to break the mirror just replace the bad disk and it rebuilds.

thanks!

 

[CrystalWizard]

on a 2104, with a raid 1, you are quite likely going to have to restore the raid once you replace the drive.

 

[haxster]

break the mirror - rmdev drive - replace drive - remirror - - - should be no reason for restore (otherwise why mirror in the first place)

 

[ctoman]

Yes, did not have to do anything just replace the bad drive and then she rebuilds.

 

[CrystalWizard]

You were very fortunate in that case.

 

[haxster]

If you have to restore then what would be the point in mirroring????

 

[CrystalWizard]

good question. In all the time I've delt with AIX, I've never seen any real point to mirroring, lvm or otherwise. Mirroring is really only useful in the rare instance that a drive experiences hardware failure and dies, without corrupting the data, and thus without copying the corruption to the mirror.

Better to use both drives in the vg for a larger vg, and do daily backups to tape.

 

[ctoman]

Description: RAID 1 is usually implemented as mirroring; a drive has its data duplicated on two different drives using either a hardware RAID controller or software (generally via the operating system). If either drive fails, the other continues to function as a single drive until the failed drive is replaced. Conceptually simple, RAID 1 is popular for those who require fault tolerance and don't need top-notch read performance. A variant of RAID 1 is duplexing, which duplicates the controller card as well as the drive, providing tolerance against failures of either a drive or a controller. It is much less commonly seen than straight mirroring