On Wed, 18 May 2005, Andy Mountford wrote:
Hi,
I am trying to configure an array of 12 disks in a RAID 10 configuration. All 12 disks are identical 146Gb drives.
First off, on each disk I created a single partition which spanned the whole disk with a system id of 0xFD. After writing the partition table, a print confirmed all looked good.
Secondly, I used mdadm to create 6 RAID 1 pairs. (mirrored).
mdadm --create /dev/md0 --level=1 -n 2 /dev/sda /dev/sdb mdadm --create /dev/md1 --level=1 -n 2 /dev/sdc /dev/sdd mdadm --create /dev/md2 --level=1 -n 2 /dev/sde /dev/sdf mdadm --create /dev/md3 --level=1 -n 2 /dev/sdg /dev/sdh mdadm --create /dev/md4 --level=1 -n 2 /dev/sdi /dev/sdj mdadm --create /dev/md5 --level=1 -n 2 /dev/sdk /dev/sdl
cat /proc/mdstat showed the devices syncing. Once this had completed I created a final meta device which striped the RAID1 meta devices. e.g.
mdadm --create /dev/md6 --level 0 -n 6 /dev/md0 dev/md1 dev/md2 dev/md3 dev/md4 dev/md5
I could then create a filesystem on the new array and mount it - all looked good. However, 2 things concerned me:
1. After creating the RAID array, the partition table for all the disks involved was empty and an fdisk returned:
"Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)"
What's going on here?
2. How can I get the array to come up after a reboot? What needs to be done? Do I need an rc script that runs mdadm?
I had a similar problem with an AS3 box that has a large RAID 0 I'd built using mdadm. Took me half a day to track it down.
The rc.sysinit script for AS3 does not check for mdadm. It only looks for raidtab. so....
Create an mdadm.conf file:
$ echo 'DEVICE partitions' > mdadm.conf $ sudo mdadm --detail --scan --confin=mdadm.conf >>mdadm.conf $ sudo c p mdadm.conf /etc/mdadm.conf
Add to rc.sysinit:
if [ -f /etc/mdadm.conf ]; then
/sbin/mdadm -A -s
fiI added it right before the line that checks for /etc/raidtab but YMMV.
-- Stephen
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