socom1985
asked on
Software RAID 5
We have an existing raid 5 from a snap nas server which brock down that we must connect with ubuntu. In this server we have only a raid controller for raid 1,2. So we have to make a software raid. We can see all the discs but not the partitions.
Is it possible to connect this raid 5 with ubuntu without losing data?
How can we do that?
Is it possible to connect this raid 5 with ubuntu without losing data?
How can we do that?
ASKER
Snap server is a nas type server with linux. Im not completly sure but I think the raid 5 was also handled by linux on the server. How can add the array to ubuntu?
Do you have the disks attached to the ubuntu server already?
Try this command (as the root user):
It should list the arrays you have attached (if recognized) in a format suitable for adding to /etc/mdadm.conf
Then to start the array you can do:
edit: this is not specific to Ubuntu, and there may be ways to achieve the same using a GUI of some sort. I'm not using Ubuntu myself though.
Try this command (as the root user):
mdadm --examine --scan
It should list the arrays you have attached (if recognized) in a format suitable for adding to /etc/mdadm.conf
Then to start the array you can do:
mdadm --assemble --scan
edit: this is not specific to Ubuntu, and there may be ways to achieve the same using a GUI of some sort. I'm not using Ubuntu myself though.
ASKER
The disks are attached to ubuntu.
The first command returns: No devices to examine
??
The first command returns: No devices to examine
??
(assuming you have restarted the server since attaching the disks) there is nothing more I can suggest on this approach unfortunately.
ASKER
After reboot we could see the arrays and attend them to the mdadm conf file and also the second command seems to work but where can we find the disk now?
oh.. great.
Let's see the output from
# cat /proc/mdstat
In the rightmost column you will see the meta device name
e.g md0
You will have a corresponding device file as /dev/md0
If the snap nas created a file system ontop of this device then you can mount it as is..
e.g mount /dev/md0 /mountpoint
If on the other hand there is logical volumes defined on this device you may need to activate them.
If the md device is shown when you run "pvscan" then this is probably the case. More about that later if necessary.
Let's see the output from
# cat /proc/mdstat
In the rightmost column you will see the meta device name
e.g md0
You will have a corresponding device file as /dev/md0
If the snap nas created a file system ontop of this device then you can mount it as is..
e.g mount /dev/md0 /mountpoint
If on the other hand there is logical volumes defined on this device you may need to activate them.
If the md device is shown when you run "pvscan" then this is probably the case. More about that later if necessary.
ASKER
For the first command we have this output (# cat /proc/mdstat)
Personalities : [raid1] [raid6] [raid5] [raid4]
md0 : inactive sde4[1] sdc4[2] sdd4[0] sdb4[3]
1949109760 blocks super 0.91
md101 : active raid1 sde5[1] sdd5[0] sdc5[2] sdb5[3]
273024 blocks [4/4] [UUUU]
md100 : active raid1 sde2[1] sdd2[0] sdc2[2] sdb2[3]
819200 blocks [4/4] [UUUU]
second comman we have this output
can't read superblock :(
Some additional information..
administrator@snapserver:/ etc$ sudo mdadm -D /dev/md0
/dev/md0:
Version : 0.91
Creation Time : Tue Feb 20 13:07:19 2007
Raid Level : raid5
Used Dev Size : 487277440 (464.70 GiB 498.97 GB)
Raid Devices : 4
Total Devices : 4
Preferred Minor : 0
Persistence : Superblock is persistent
Update Time : Sun Feb 5 21:50:36 2012
State : active, Not Started
Active Devices : 4
Working Devices : 4
Failed Devices : 0
Spare Devices : 0
Layout : left-symmetric
Chunk Size : 64K
New Level : raid0
New Chunksize : 0K
UUID : 8c4707de:35781ade:d371f49d :65ac14b1
Events : 0.26137743
Number Major Minor RaidDevice State
0 8 52 0 active sync /dev/sdd4
1 8 68 1 active sync /dev/sde4
2 8 36 2 active sync /dev/sdc4
3 8 20 3 active sync /dev/sdb4
Personalities : [raid1] [raid6] [raid5] [raid4]
md0 : inactive sde4[1] sdc4[2] sdd4[0] sdb4[3]
1949109760 blocks super 0.91
md101 : active raid1 sde5[1] sdd5[0] sdc5[2] sdb5[3]
273024 blocks [4/4] [UUUU]
md100 : active raid1 sde2[1] sdd2[0] sdc2[2] sdb2[3]
819200 blocks [4/4] [UUUU]
second comman we have this output
can't read superblock :(
Some additional information..
administrator@snapserver:/
/dev/md0:
Version : 0.91
Creation Time : Tue Feb 20 13:07:19 2007
Raid Level : raid5
Used Dev Size : 487277440 (464.70 GiB 498.97 GB)
Raid Devices : 4
Total Devices : 4
Preferred Minor : 0
Persistence : Superblock is persistent
Update Time : Sun Feb 5 21:50:36 2012
State : active, Not Started
Active Devices : 4
Working Devices : 4
Failed Devices : 0
Spare Devices : 0
Layout : left-symmetric
Chunk Size : 64K
New Level : raid0
New Chunksize : 0K
UUID : 8c4707de:35781ade:d371f49d
Events : 0.26137743
Number Major Minor RaidDevice State
0 8 52 0 active sync /dev/sdd4
1 8 68 1 active sync /dev/sde4
2 8 36 2 active sync /dev/sdc4
3 8 20 3 active sync /dev/sdb4
The array was not started it seems (may need entries in mdadm.conf for that to happen - not sure)
Try
# mdadm --run /dev/md0
Try
# mdadm --run /dev/md0
ASKER
mdadm: failed to run array /dev/md0: Invalid argument
am I missing something?
am I missing something?
ASKER
I also tried this:
sudo mdadm --assemble /dev/md0 /dev/sdd4 /dev/sde4 /dev/sdc4 /dev/sdb4
mdadm: Failed to restore critical section for reshape, sorry.
Possibly you needed to specify the --backup-file
sudo mdadm --assemble /dev/md0 /dev/sdd4 /dev/sde4 /dev/sdc4 /dev/sdb4
mdadm: Failed to restore critical section for reshape, sorry.
Possibly you needed to specify the --backup-file
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If the "snap nas server" used a hardware raid controller you are not likely (not without writing drivers to emulate the controller anyway) going to be able to read the data using software raid.
What more can you tell us about the original "snap nas server" setup?