Software RAID1 problems, won't take /dev/sdb2 ?

michaelsanford · 06-20-2005, 02:07 PM

http://slacksite.com/slackware/raid.html

I have only two partitions, swap and /, which ar identical in every respect on both disks. I boot from /dev/sdb2. I've managed to create the /dev/md0 device and add /dev/sda2 but when I try to issue `raidhotadd /dev/md0 /dev/sdb2` I get the error /dev/md0: can not hot-add disk: invalid argument.

Why is it an invalid argument? I can add /dev/sdb (which I did accidentally a few times) which of course just wipes the whole disk.

Is it because it's still a failed-disk in /etc/raidtab ?

marvin00001 · 06-20-2005, 02:17 PM

Please can you post your partition table

michaelsanford · 06-20-2005, 02:25 PM

Gladly

Code:

gateway:~# fdisk -l /dev/sda

Disk /dev/sda: 122.9 GB, 122942324736 bytes
255 heads, 63 sectors/track, 14946 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1           14823       14946      996030    5  Extended
/dev/sda2   *           1       14822   119057683+  fd  Linux raid autodetect
/dev/sda5           14823       14946      995998+  82  Linux swap

Partition table entries are not in disk order
root@gateway:~# fdisk -l /dev/sdb

Disk /dev/sdb: 122.9 GB, 122942324736 bytes
255 heads, 63 sectors/track, 14946 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1           14823       14946      996030    5  Extended
/dev/sdb2   *           1       14822   119057683+  fd  Linux raid autodetect
/dev/sdb5           14823       14946      995998+  82  Linux swap

Partition table entries are not in disk order

EDIT I may have just totally fluked myself the answer. I'll post more when the recovery is done--around 32 minutes.

SECOND EDIT Yeah I got it working. I also found a MUCH simpler way of doing software RAID than that guide above (though it relies on a clean system). I'll write a how-to later.

kicko · 01-08-2006, 04:35 AM

Could you please post your guide to make RAID?

michaelsanford · 01-08-2006, 07:46 PM

Yeah, guess I never got around to doing that

My guide is simple. Make both disks the same partition scheme, type RAID Autodetect (except for the swap partitions) and THEN install the system as you would normally. Slackware should recognize only one installation device: md0. You'll; have to play around with the installation location of lilo to get it to work on your setup. I believe I installed mine on the 'root partition (potentially unsafe)'.

Additional: The first time you boot it will warn you that "The RAID array md0 is not clean! Repairing" or somehting like that. You'll then notice the HD access lights going nuts for a good long time, and a process called 'raidchk' or 'repair_raid' or something of that nature taking up some CPU cycles. That's normal; it's rebuilding your RAID array, let it finish ! And don't worry, it may take a long time, but it won't take forever.

On my Athlon64 2.4 GHz with 2 GB RAM and nothing running it took something like 3 hours...