Topic: RAID1 with mismatched drives ??

[Ray Mitchell]

Dear All

I installed v5.5 on a test server in software RAID1 with a 4.2Gb and a 4.3 Gb IDE drives, and after installing df -h reports 1.8Gb disk space.
As it is a test server and I do not happen to have exactly matching spare drives, the disk space loss is not a problem.

Is it OK to run the system like that in RAID1, I just want to have an actual RAID1 setup for pre production testing etc, but am concerned as to whether there is  likely to be any data corruption at all with this setup ?

I know that when setting up software RAID1 on sme v5.5 the advice is to use hard disk drives that have the same geometry.
I did go through the process of "clearing" the partition info with
dd if=/dev/zero of=/dev/hda bs=512 count=1
dd if=/dev/zero of=/dev/hdc bs=512 count=1
but after reinstallation I still got 1.8Gb reported disk space, but that is acceptable, it's enough space for test purposes.

cat /proc/mdstat
reports successful syncing of the drives.

Thanks
Ray Mitchell

[Ray Mitchell]

Dear All
For the benefit of others who may run into this problem, it was able to be resolved much more satisfactorily as follows.

Apparently the Red Hat installer does not always identify RAID configurations correctly and can create undesired partitions.
Using concepts from the v5.6 instal process, part of the ks.cfg file on the boot disk was edited as follows.

part raid.00 --size 10 --ondisk hda
part raid.01 --size 10 --ondisk hdc
part raid.10 --size 1 --grow --ondisk hda
part raid.11 --size 1 --grow --ondisk hdc
part raid.20 --size 256 --ondisk hda
part raid.21 --size 256 --ondisk hdc

Then I did a reboot using the boot disk and a reinstall of v5.5 in software RAID1.
After that the partitions were correct AND the reported disk space was now 3.6Gb rather than the previous 1.8Gb.

Many thanks to Charlie Brady for his assistance.

Regards
Ray Mitchell

[Angus]

Dear all,

Replace HDA and HDC with SDA and SDB for scsi disks on single controller works as well.

I had a Wester Digital and an IBM 9gb, and they would only get me 4gb.

Create the boot disk, and edit the sections as above, replacing with my drives worked a treat.

Thanks.
Angus