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Table of Contents
SW RAID Quick reference
Create a RAID 1 volume from two drives.
mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/sdc /dev/sde
To add RAID device 'md0' to /etc/mdadm.conf so that it is recognized the next time you boot.
mdadm -Es | grep '''md0''' >>/etc/mdadm.conf
View the status of a multi disk array.
mdadm --detail /dev/md0
View the status of all multi disk arrays.
cat /proc/mdstat
Note: add raid1 to /etc/initramfs-tools/modules and rebuild initrd
Grow sw raid
Situation: Raid 5, with 6 disks
Final: Raid 5, with 8 disks
# mdadm --add /dev/md127 /dev/sdh1 mdadm: added /dev/sdh1 # mdadm --add /dev/md127 /dev/sdj1 mdadm: added /dev/sdj1 # mdadm --grow --raid-devices=8 /dev/md127 mdadm: Need to backup 1344K of critical section.. mdadm: ... critical section passed. #
Nekdy se muze hodit:
tags: 3ware tw_cli replace drive
echo "0 0 0" > /sys/bus/scsi/devices/0\:0\:4\:0/rescan
Links
Frozen spare
# mdadm --detail /dev/md0
/dev/md0:
Version : 1.2
Creation Time : Sat Feb 2 06:51:55 2013
Raid Level : raid6
Array Size : 11717889024 (11175.05 GiB 11999.12 GB)
Used Dev Size : 1952981504 (1862.51 GiB 1999.85 GB)
Raid Devices : 8
Total Devices : 8
Persistence : Superblock is persistent
Update Time : Mon Jul 15 20:30:57 2013
State : active, degraded
Active Devices : 7
Working Devices : 8
Failed Devices : 0
Spare Devices : 1
Layout : left-symmetric
Chunk Size : 512K
Name : tukan2:0 (local to host tukan2)
UUID : bf36da8d:5009d151:4f3ee49d:92059128
Events : 1535927
Number Major Minor RaidDevice State
0 8 17 0 active sync /dev/sdb1
1 8 33 1 active sync /dev/sdc1
2 8 49 2 active sync /dev/sdd1
3 8 65 3 active sync /dev/sde1
4 8 97 4 active sync /dev/sdg1
5 0 0 5 removed
6 8 129 6 active sync /dev/sdi1
7 8 145 7 active sync /dev/sdj1
8 8 113 - spare /dev/sdh1
# cat /sys/block/md0/md/sync_action frozen
echo repair >/sys/block/md0/md/sync_action
Result:
# mdadm --detail /dev/md0
/dev/md0:
Version : 1.2
Creation Time : Sat Feb 2 06:51:55 2013
Raid Level : raid6
Array Size : 11717889024 (11175.05 GiB 11999.12 GB)
Used Dev Size : 1952981504 (1862.51 GiB 1999.85 GB)
Raid Devices : 8
Total Devices : 8
Persistence : Superblock is persistent
Update Time : Mon Jul 15 20:38:59 2013
State : active, degraded, recovering
Active Devices : 7
Working Devices : 8
Failed Devices : 0
Spare Devices : 1
Layout : left-symmetric
Chunk Size : 512K
Rebuild Status : 0% complete
Name : tukan2:0 (local to host tukan2)
UUID : bf36da8d:5009d151:4f3ee49d:92059128
Events : 1536481
Number Major Minor RaidDevice State
0 8 17 0 active sync /dev/sdb1
1 8 33 1 active sync /dev/sdc1
2 8 49 2 active sync /dev/sdd1
3 8 65 3 active sync /dev/sde1
4 8 97 4 active sync /dev/sdg1
8 8 113 5 spare rebuilding /dev/sdh1
6 8 129 6 active sync /dev/sdi1
7 8 145 7 active sync /dev/sdj1
Speed Up
echo 6144 > /sys/block/md3/md/stripe_cache_size echo 40000 > /proc/sys/dev/raid/speed_limit_min echo 256000 > /proc/sys/dev/raid/speed_limit_max
3ware Utility
- http://www.3ware.com/support/download.asp (the 900kB one!)
/c0 add type=SINGLE disk=0
3ware smart
smartctl -d 3ware,1 -a /dev/twa0 smartctl -d 3ware,8 -a /dev/twa0 -T permissive
IBM ServeRAID Utility
ibm_utl_aacraid_9.10_linux_32-64.zip
HP Smart Array
HP DL360 G6 P410i * http://h20000.www2.hp.com/bizsupport/TechSupport/SoftwareIndex.jsp?lang=en&cc=us&prodNameId=3902575&prodTypeId=329290&prodSeriesId=3902574&swLang=8&taskId=135&swEnvOID=4004
At Debian you need to
apt-get install ia32-libs
and hpacucli-8.75-12.0.noarch.rpm. Example:
controller all show config ctrl slot=0 create type=ld drives=1I:1:3 raid=0
RAID10 performance
mdadm -v --create /dev/md0 --level=raid10 --layout=f2 --raid-devices=4 ...
The trick is “layout=f2” as the man page says>
Finally, the layout options for RAID10 are one of 'n', 'o' or 'f' followed by a small number. The default is 'n2'. The supported options are:
'n' signals 'near' copies. Multiple copies of one data block are at similar offsets in different devices.
'o' signals 'offset' copies. Rather than the chunks being duplicated within a stripe, whole stripes are duplicated but are rotated by one device so
duplicate blocks are on different devices. Thus subsequent copies of a block are in the next drive, and are one chunk further down.
'f' signals 'far' copies (multiple copies have very different offsets). See md(4) for more detail about 'near', 'offset', and 'far'.
The number is the number of copies of each datablock. 2 is normal, 3 can be useful. This number can be at most equal to the number of devices in the
array. It does not need to divide evenly into that number (e.g. it is perfectly legal to have an 'n2' layout for an array with an odd number of
devices).
Setting up RAID10 with tw_cli
Generating the RAID10 field with disks in ports from 8 to 17:
./tw_cli /c0 add type=raid10 disk=8-17 noautoverify
Software way of removing a disk from port 14:
./tw_cli maint remove c0 p14
Taking a look of what has it done:
./tw_cli /c0/u0 show
“Adding” a disk back to the file system (more like identifying it):
./tw_cli maint rescan c0
Starting the verification process (if the unit was not previously initialized, it will be):
./tw_cli /c0/u0 start verify
If you need to check which disk is connected to each port, you can use this command, it will light the external GUI light:
./tw_cli /c0/p16 set identify=on
Add disk to raid:
tw-cli /c0/u0 start rebuild disk=16
If the disk is in another unit (i.e. u1), just delete the unit
tw-cli /c0/u1 del
Problem: after physically removing a disk and installing it back, RAID started re-initializing by its own will without letting the master know. It's just bad.