Software RAID Configuration problem

Mathew Snyder theillien at yahoo.com
Sat Oct 28 03:28:08 UTC 2006


I posted this to rhn-users before realizing there is an actual sysadmin
list so I'm posting it here now.

I have an RHEL 4 AS virtual machine running under VMWare with the
following configuration:

/dev/sda1 /     650M
/dev/sda2 /var  500M
/dev/sda3 /home 500M (Linux raid autodetect for software raid)
/dev/sda4 Extended partition
/dev/sda5 swap  128M

/dev/sdb1 /usr  1.65G
/dev/sdb2 /tmp  100M
/dev/sdb3 Linux raid autodetect for software raid with /dev/sda3)

Here's the run down:  I started with a single /home partition on
/dev/sda and plenty of unallocated space on /dev/sdb.  I followed
directions in Michael Jang's RHCE book for mirroring the /home
partition.  They are as follows:

Copy the /home data to /tmp then

# unmount /home
# fdisk /dev/sda
Command (m for help) : t
Partition number (1-4)
3
Partition ID (L to list options): FD
Command (m for help) : w

# fdisk /dev/sdb
Command (m for help) : t
Partition number (1-4)
4
Partition ID (L to list options): FD
Command (m for help) : w

I then edit /etc/raidtab and add the following information:
raiddev /dev/md0
raid-level 1

nr-raid-disks 2
nr-spare-disk 0
persistent-superblock 1
chunck-size 4
device /dev/sda3
raid-disk 0
device /dev/sdb4
raid-disk 1


I then create the raid and format it:
# mkraid -R /dev/md0 (this runs to completion with no errors)
# mkfs -j /dev/md0

I then run e2label so I can apply a label to /dev/md0 and use the
LABEL=/home entry in /etc/fstab.  However, when I reboot it says it
can't mount the special device: LABEL=/home no such device, etc.

When I log in, I run e2label on /dev/md0 and it isn't found.  If I run
e2label on either /dev/sda3 or /dev/sdb4 it comes back with /home.

If I mount /dev/md0 it mounts fine.

I've changed the format command to `mke2fs -j -L /home /dev/md0`
thinking it would give me better results but they end up the same.  It
won't mound /dev/md0 based on the label alone.

What might I be doing wrong?

Thanks,
Mathew Snyder




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