Software RAID1 on a Running Debian System

[amras86]

Hey,

I recently tried the software RAID1 tutorial for Debian Etch on a virtual machine, it worked flawlessly. Now when I tried to implement it into a working environment with a real server and 2x80 GB SATA hard drives, the /boot and swap partitions synchronize properly, but when it do the root partition, I get an error saying that the device is busy or unavailable. I tried forcing it, unmounting and remounting it, nothing works. I've searched Google for people having the same problem and nobody can fix it for some reason, any ideas? Just something I think I should mention though I doubt it makes a difference, the hard drives are a Seagate and a Western Digital. I tried this with 2 20 GB Maxtors of the same model and still a no go.

[falko]

Do you mean this tutorial? http://www.howtoforge.com/software-r...ot-debian-etch

At which step exactly are you facing this problem?

[amras86]

Yeah, thats the tutorial I am having trouble with. The particular section that I am talking about is in section 7, Preparing /dev/sda. Its these steps in particular,

mdadm --add /dev/md0 /dev/sda1
mdadm --add /dev/md1 /dev/sda2
mdadm --add /dev/md2 /dev/sda3

The first two commands work flawlessly and I can use the watch command to view the synchronization in progress, but when I do the sda3 command I get an error saying the device is busy or unavailable. Again I've search around Google with people with the same problem and it seems to be a serious problem. I've tried remounting, forcing the synchronization with the --force attribute.

[falko]

What's the output of

fdisk -l

?

[rodti]

Hi Falko,

Sorry to hijack an old thread but I'm having a similar problem with this how-to.

I have two partitions, a 2GB swap and a 150GB+ ext3 partition. I'm trying to make md0 (sda1+sdb1) and md1 (sda2+sdb2) respectively out of these.

Following the how-to I've managed to make a RAID1 md0 swap volume. Unfortunately I get the following error when attempting to add sda2 to md1:

root@lime:~# mdadm --add /dev/md1 /dev/sda2
mdadm: Cannot open /dev/sda2: Device or resource busy

Here is the output of /proc/mdstat:

root@lime:~# cat /proc/mdstat
Personalities : [linear] [raid0] [raid1] [raid5] [multipath] [raid6] 
md1 : active raid1 sdb2[1]
      154191744 blocks [2/1] [_U]
      
md0 : active raid1 sda1[0] sdb1[1]
      2096384 blocks [2/2] [UU]

And fdisk -l:

root@lime:~# fdisk -l

Disk /dev/sda: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1               1         261     2096451   fd  Linux raid autodetect
/dev/sda2             262       19457   154191870   fd  Linux raid autodetect

Disk /dev/sdb: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1         261     2096451   fd  Linux raid autodetect
/dev/sdb2             262       19457   154191870   fd  Linux raid autodetect

Disk /dev/md0: 2146 MB, 2146697216 bytes
2 heads, 4 sectors/track, 524096 cylinders
Units = cylinders of 8 * 512 = 4096 bytes

Disk /dev/md0 doesn't contain a valid partition table

Disk /dev/md1: 157.8 GB, 157892345856 bytes
2 heads, 4 sectors/track, 38547936 cylinders
Units = cylinders of 8 * 512 = 4096 bytes

Disk /dev/md1 doesn't contain a valid partition table

Any help appreciated!

[falko]

Did you boot the system from /dev/sdb or /dev/sda? Should be /dev/sdb.

[Leszek]

Hi,

I'm having the same problem.
After installing CentOS there's almost nothing I can do with my arrays.
I always get:

mdadm: cannot open /dev/sda1: Device or resource busy

Please help.

[falko]

Is it possible that the system is currently running on /dev/sda1?

[Leszek]

Yes it is but I get the same error for /dev/md1 and /dev/md2.
Booting from CentOS DVD (by entering linux rescue) doesn't actually help. Everything remains the same.

[falko]

What's the output of

mount

when the system is running on md1 and md2?