Softraid on OpenBSD
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Softraid
Inspired by a book from MWL - OpenBSD Mastery Filesystems, here some Notes ..
Target
build a RAID with 3 Disks, add some Data, destroy one Disk, and rebuild the Raid (and it’s Data).
Requirements
- OpenBSD 7.2 Running
- added 3 Disk with 20G each: sd0, sd1, sd2
Find Disks
root@puffy # dmesg |grep -i sec
wd0: 64-sector PIO, LBA, 20480MB, 41943040 sectors
sd0: 20480MB, 512 bytes/sector, 41943040 sectors
sd1: 20480MB, 512 bytes/sector, 41943040 sectors
sd2: 20480MB, 512 bytes/sector, 41943040 sectors
sd0, sd1, sd2 are New Disks for RAID
Write GPT Table
fdisk -gy sd0
fdisk -gy sd1
fdisk -gy sd2
Set Filesystem to Raid
root@puffy # disklabel -E sd0
Label editor (enter '?' for help at any prompt)
sd0> a
partition: [a]
offset: [64]
size: [41942943]
FS type: [4.2BSD] raid
sd0*> w
sd0> q
No label changes.
Dump Disklabel, apply the Label to other Disks
if your disks have different sizes, you need to find the smallest one and apply that schema to the other disks
disklabel sd0 > disklabel.sd0.softraid
disklabel -R sd1 disklabel.sd0.softraid
disklabel -R sd2 disklabel.sd0.softraid
Create Raid5
root@puffy # bioctl -c 5 -l sd0a,sd1a,sd2a softraid0
softraid0: RAID 5 volume attached as sd3
Zeroize Raid
root@puffy # dd if=/dev/zero bs=1m count=1 of=/dev/sd3c
1+0 records in
1+0 records out
1048576 bytes transferred in 0.068 secs (15227879 bytes/sec)
make Partition on Raid
root@puffy # fdisk -gy sd3
Writing GPT.
# disklabel -E sd3
Label editor (enter '?' for help at any prompt)
sd3> a
partition: [a]
offset: [64]
size: [83884703]
FS type: [4.2BSD]
sd3*> w
sd3> q
No label changes.
Build new FileSystem
root@puffy # newfs sd3a
/dev/rsd3a: 40959.3MB in 83884672 sectors of 512 bytes
203 cylinder groups of 202.50MB, 12960 blocks, 25920 inodes each
super-block backups (for fsck -b #) at:
160, 414880, 829600, 1244320, 1659040, 2073760, 2488480, 2903200, 3317920, 3732640, 4147360, 4562080, 4976800, 5391520,
5806240, 6220960, 6635680, 7050400, 7465120, 7879840, 8294560, 8709280, 9124000, 9538720, 9953440, 10368160, 10782880,
11197600, 11612320, 12027040, 12441760, 12856480, 13271200, 13685920, 14100640, 14515360, 14930080, 15344800, 15759520,
16174240, 16588960, 17003680, 17418400, 17833120, 18247840, 18662560, 19077280, 19492000, 19906720, 20321440, 20736160,
21150880, 21565600, 21980320, 22395040, 22809760, 23224480, 23639200, 24053920, 24468640, 24883360, 25298080, 25712800,
26127520, 26542240, 26956960, 27371680, 27786400, 28201120, 28615840, 29030560, 29445280, 29860000, 30274720, 30689440,
31104160, 31518880, 31933600, 32348320, 32763040, 33177760, 33592480, 34007200, 34421920, 34836640, 35251360, 35666080,
36080800, 36495520, 36910240, 37324960, 37739680, 38154400, 38569120, 38983840, 39398560, 39813280, 40228000, 40642720,
41057440, 41472160, 41886880, 42301600, 42716320, 43131040, 43545760, 43960480, 44375200, 44789920, 45204640, 45619360,
46034080, 46448800, 46863520, 47278240, 47692960, 48107680, 48522400, 48937120, 49351840, 49766560, 50181280, 50596000,
51010720, 51425440, 51840160, 52254880, 52669600, 53084320, 53499040, 53913760, 54328480, 54743200, 55157920, 55572640,
55987360, 56402080, 56816800, 57231520, 57646240, 58060960, 58475680, 58890400, 59305120, 59719840, 60134560, 60549280,
60964000, 61378720, 61793440, 62208160, 62622880, 63037600, 63452320, 63867040, 64281760, 64696480, 65111200, 65525920,
65940640, 66355360, 66770080, 67184800, 67599520, 68014240, 68428960, 68843680, 69258400, 69673120, 70087840, 70502560,
70917280, 71332000, 71746720, 72161440, 72576160, 72990880, 73405600, 73820320, 74235040, 74649760, 75064480, 75479200,
75893920, 76308640, 76723360, 77138080, 77552800, 77967520, 78382240, 78796960, 79211680, 79626400, 80041120, 80455840,
80870560, 81285280, 81700000, 82114720, 82529440, 82944160, 83358880, 83773600,
Mount Raid
root@puffy # mkdir /raid
root@puffy # mount /dev/sd3a /raid
make mount persistent
echo "/dev/$(bioctl softraid0 |awk '/softraid0/{ print $5 }')a /raid ffs rw,softdep,noatime,nodev,nosuid 1 2" >> /etc/fstab
df
root@puffy # df -h
Filesystem Size Used Avail Capacity Mounted on
/dev/wd0a 600M 224M 346M 39% /
/dev/wd0l 3.7G 63.7M 3.4G 2% /home
/dev/wd0d 848M 1.7M 804M 0% /tmp
/dev/wd0f 2.3G 1.2G 1.0G 54% /usr
/dev/wd0g 643M 271M 339M 44% /usr/X11R6
/dev/wd0h 2.3G 1.7G 493M 78% /usr/local
/dev/wd0k 5.2G 2.0K 4.9G 0% /usr/obj
/dev/wd0j 1.6G 2.0K 1.5G 0% /usr/src
/dev/wd0e 1.2G 49.8M 1.1G 4% /var
/dev/sd3a 38.7G 2.0K 36.8G 0% /raid
Create Data
root@puffy # tar czf /raid/all.tar.gz / &
root@puffy # df -h /raid/;
Filesystem Size Used Avail Capacity Mounted on
/dev/sd3a 38.7G 2.2G 34.6G 6% /raid
root@puffy# ls -al /raid/
drwxr-xr-x 2 root wheel 512 Feb 4 11:18 .
drwxr-xr-x 14 root wheel 512 Feb 4 11:18 ..
-rw-r--r-- 1 root wheel 2374055353 Feb 4 11:22 all.tar.gz
Raid Status
root@puffy 130 # bioctl softraid0
Volume Status Size Device
softraid0 0 Online 42949017600 sd3 RAID5
0 Online 21474516480 0:0.0 noencl <sd0a>
1 Online 21474516480 0:1.0 noencl <sd1a>
2 Online 21474516480 0:2.0 noencl <sd2a>
let’s reboot, remove one disk and replace it with an empty, bigger one …
New Disk
root@puffy # dmesg |grep -i sect
wd0: 64-sector PIO, LBA, 20480MB, 41943040 sectors
sd0: 20480MB, 512 bytes/sector, 41943040 sectors
sd1: 20480MB, 512 bytes/sector, 41943040 sectors
sd2: 30720MB, 512 bytes/sector, 62914560 sectors
sd3: 40959MB, 512 bytes/sector, 83884800 sectors
Check Raid Status
root@puffy # bioctl softraid0
Volume Status Size Device
softraid0 0 Degraded 42949017600 sd3 RAID5
0 Online 21474516480 0:0.0 noencl <sd0a>
1 Offline 0 0:1.0 noencl <>
2 Online 21474516480 0:2.0 noencl <sd1a>
Data still Safe ?
root@puffy # ll /raid/
total 4639136
-rw-r--r-- 1 root wheel 2374055353 Feb 4 11:22 all.tar.gz
Rebuild Raid
root@puffy # bioctl -R /dev/sd2a sd3
softraid0: sd2a partition too large, wasting 10737418240 bytes
softraid0: rebuild of sd3 started on sd2a
Rebuild Progress
root@puffy # bioctl sd3
Volume Status Size Device
softraid0 0 Rebuild 42949017600 sd3 RAID5 10% done
0 Online 21474516480 0:0.0 noencl <sd0a>
1 Rebuild 32211934720 0:1.0 noencl <sd2a>
2 Online 21474516480 0:2.0 noencl <sd1a>
seems working fine !
Problems
-
created more than one Bluescreen while reading and writing to the RAID
-
added 4.th Disk to VM -> RAID Volume (softraid0 -> sd3) got renamed to sd4, while the new Disk got inserted as sd3
-> RAID was broken until i remove the new Disk and did a reboot :(
softraid0: volume sd4 is roaming, it used to be sd3, updating metadata
Any Comments ?
sha256: d69126086aa0db837e03b8ad8b02f2e54a1642a265dc5d4d1f2ddc852b728d76