Copy partition layout from sdb to sdc and so forth:
# sfdisk -d /dev/sdb | sfdisk /dev/sdc
Let the kernel probe the new partitions:
# partprobe
Create RAID5 from sd[bcde]1. The -a yes instructs mdadm to create the device file if needed, possibly allocating an unused minor number:
# mdadm -C -a yes /dev/md0 --level=5 --raid-devices=4 /dev/sdb1 \
/dev/sdc1 /dev/sdd1 /dev/sde1
Or create RAID0 (just change the --level):
# mdadm --create /dev/md0 --level=raid0 --raid-devices=4 /dev/sdb1 \
/dev/sdc1 /dev/sdd1 /dev/sde1
Add a disk to the existing raid5 array. The disk will be added as a spare:
# mdadm --add /dev/md1 /dev/sda8
To make disk regular part of an array (disk will not longer be a spare):
# mdadm --grow /dev/md1 --raid-devices=4
Resize the filesystem:
# resize2fs /dev/md1
Check the status og the newly created RAID:
# cat /proc/mdstat
Detailed statistics about your RAID:
# mdadm --misc --detail --test /dev/md0
Run backgroudn monitor of your RAID setup with mdadm. Add the RAID monitoring into /etc/rc.local. Linux box will mail you an message when the thing goes wrong.
/sbin/mdadm --monitor --mail=root@localhost \
--delay=300 /dev/md0 /dev/md1 &
Or enable monitoring with daemon:
# chkconfig mdmonitor on
# echo "MAILADDR root@mydomain.tld " >> /etc/mdadm.conf
# /etc/init.d/mdmonitor start
To test if the background monitoring works generate a test alert.
# mdadm --monitor /dev/md0 --test
Remove failed disk from the array:
# mdadm /dev/md1 -r /dev/sdc2
Put the disk back:
# mdadm /dev/md1 -a /dev/sdc2
Check the /etm/mdadm.conf after building raid. If the /etc/mdadm.conf is empty then you can regenerate:
mdadm --detail --scan > /etc/mdadm.conf
If the radid is not visible after reboot:
# mdadm --assemble /dev/md0 /dev/sd[e-h]
or
# mdadm -A -s (-s scan)
Stop the array (f.x. rebuilding array):
# mdadm --manage -S /dev/md0
Detailed info about /dev/md0:
# mdadm --detail /dev/md0
If you want the mirrored rootdisks will ableo to boot even with second mirror then you have to write the boot loader as well to the second disk. Some distros does not do that.
# cat /proc/mdstat
Personalities : [raid1]
md1 : active raid1 hdd2[1] hdc2[0]
2048192 blocks [2/2] [UU]
md2 : active raid1 hdd3[1] hdc3[0]
16546880 blocks [2/2] [UU]
md0 : active raid1 hdd1[1] hdc1[0]
20482752 blocks [2/2] [UU]
# cat /etc/grub.conf | grep "root (" | uniq
root (hd0,0)
Then run "grub" and type:
grub> root (hd1,0); setup (hd1)
To apply bootloader.
Zero supeblock:
# mdadm --zero-superblock /dev/sdb
Filesystem benchmarking tool bonnie++ on SourceForge.org + RMP bonnie++ for CentOS.
Scan for RAID:
[root@xen stopped_xen]# mdadm --detail --scan -vv
/dev/md0:
Version : 00.90.03
Creation Time : Fri Mar 27 16:36:52 2009
Raid Level : raid6
Array Size : 1953535744 (1863.04 GiB 2000.42 GB)
Used Dev Size : 488383936 (465.76 GiB 500.11 GB)
Raid Devices : 6
Total Devices : 6
Preferred Minor : 0
Persistence : Superblock is persistent
Update Time : Sun Mar 29 20:46:28 2009
State : active
Active Devices : 6
Working Devices : 6
Failed Devices : 0
Spare Devices : 0
Chunk Size : 64K
UUID : 78f01f82:67630b8b:5eaaf972:4ecf197a
Events : 0.17
Number Major Minor RaidDevice State
0 8 33 0 active sync /dev/sdc1
1 8 49 1 active sync /dev/sdd1
2 8 65 2 active sync /dev/sde1
3 8 81 3 active sync /dev/sdf1
4 8 97 4 active sync /dev/sdg1
5 8 113 5 active sync /dev/sdh1
Remove RAID:
mdadm --manage /dev/mdfoo --fail /dev/sdfoo
mdadm --manage /dev/mdfoo --remove /dev/sdfoo
mdadm --manage --stop /dev/mdfoo
985 mdadm --detail --scan -vv
986 mdadm --manage /dev/md0 --fail /dev/sdc1
987 mdadm --manage /dev/md0 --fail /dev/sdd1
988 mdadm --manage /dev/md0 --fail /dev/sde1
989 mdadm --manage /dev/md0 --fail /dev/sdf1
990 mdadm --manage /dev/md0 --fail /dev/sdg1
991 mdadm --manage /dev/md0 --fail /dev/sdh1
992 mdadm --detail --scan -vv
993 mdadm --manage --stop /dev/md0
994 mdadm --detail --scan -vv
995 reboot
996 cat /proc/mdstat
997 ls -la /dev/md0
998 mdadm --detail --scan -vv
999 mdadm --remove /dev/md0
1000 cat /proc/mdstat
1005 fdisk /dev/sdd (t82)
1006 fdisk /dev/sde (t82)
1007 fdisk /dev/sdf (t82)
1008 fdisk /dev/sdg (t82)
1009 fdisk /dev/sdg (t82)
1010 fdisk /dev/sdh (t82)
1021 mdadm --zero-superblock /dev/sdc
1022 mdadm --zero-superblock /dev/sdc
1023 mdadm --zero-superblock /dev/sdc1
1024 mdadm --zero-superblock /dev/sdd1
1025 mdadm --zero-superblock /dev/sde1
1026 mdadm --zero-superblock /dev/sdf1
1027 mdadm --zero-superblock /dev/sdg1
1028 mdadm --zero-superblock /dev/sdh1
[ add comment ] ( 4 views ) | [ 0 trackbacks ] | permalink
Calendar
