Adding mirror disk to an A class

[Mark McDonald]

Hi

I have an A500 machine with 2 internal disks (18Gb) 1 for the unix and 1 for the aplication.

I wish to add mirror disk to this (using MirrorUX) . Can i sinply attach an external disk exclosure with 2 disks and mirror to this? Is there a better way?

What would be a suitable disk enclosure?

Thanks in advance

Mark McDonald

[Mark Grant]

You don't mirror disks as such, you mirror logical volumes. Logical volumes live within volume groups. So what you need to do is have all the disk you need within the same volume group and then mirror the logical volumes you want.

If your unix stuff is in vg00 and your applications are in vg01 I would suggest you actually moved vg01 to the new externals disks. THe simplest way to do this would be to add the new disks to vg01 (using vgextend) and then mirror all the logical volumes of vg01 onto one of the new disks (see lvextend -m) then mirror it again onto the second external disk. In effect you then have three mirrors. Break the original mirror (see lvreduce -m) so that you end up with vg01 mirrored on your external disks. Then remove the internal disk from vg01 with vgreduce and vgextend vg00 to include it. You can then mirror your "unix" disk onto the newly freed up internal disk.

I hope this helps in some way.

[Stefan Stechemesser · Accepted solution]

Hi,

I would recomend to obtain a DS2100 (Product No: A5676A, 4 slot enclosure) with two 18 GB disk (f.e. PN A6537A) and attach it to the external Ultra2 SCSI connector on the A-Class. Then you can mirror your disks (your logical volumes) and you have redundancy against a disk failure and a SCSI bus problem.