Page 1 of 1

Adding a disk to a raid 5

Posted: 2005/08/19 16:10:46
by justinc
I have a server at home running CentOS 4.x

Currently there are 4x160GB sata drives in a raid 5 configuration. I want to add another 160 GB disk because i'm running low on space. Is there a good how-to out there to do this, I just want to make sure everything is correct and don't loose data. LVM2 is also on top of the Raid 5 (software raid). All of my data is backed up to an external SATA 2x250GB LVM2 box, so I'm not real worried about the raid5 exploding, but i would rather not loose it all and rsyn 300GB+ of data.

md2 is the raid 5 I want to add another disk to and VolGroup01 is the raid 5

# cat /proc/mdstat
Personalities : [raid1] [raid5]
md1 : active raid1 hdd2[1] hda2[0]
38973568 blocks [2/2] [UU]

md2 : active raid5 sdd1[1] sdc1[3] sdb1[0] sda1[2]
468864768 blocks level 5, 256k chunk, algorithm 2 [4/4] [UUUU]

md0 : active raid1 hdd1[1] hda1[0]
104320 blocks [2/2] [UU]

# vgdisplay VolGroup01
--- Volume group ---
VG Name VolGroup01
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 16
VG Access read/write
VG Status resizable
Cur LV 2
Open LV 2
Max PV 0
Cur PV 1
Act PV 1
VG Size 447.12 GB
PE Size 32.00 MB
Total PE 14308
Alloc PE / Size 12640 / 395.00 GB
Free PE / Size 1668 / 52.12 GB
VG UUID ecefLX-oL6e-G10i-Hbu1-bRSy-RWJf-VkWpCG

cat /etc/mdadm.conf

# mdadm.conf written out by anaconda
DEVICE partitions
ARRAY /dev/md1 super-minor=1
ARRAY /dev/md2 super-minor=2
ARRAY /dev/md0 super-minor=0