Can't add missing member back in???
Hi,
Interesting problem. I'm setting up an all software RAID system and after a few fits and starts have reached some success. I started to do some testing and have run into a problem. What I was doing is I was one by one unplugging one of the SCSI drives and then powering up the system to make sure it would power up properly. The first time I did this everything worked great. I plugged the drive back up and used raidhotadd to recover and got everything to UUU. I then powered off and unplugged another drive, system boots up great with only two drives. Now its time to plug the drive back in and rebuild the array to be ready to unplug the last of the three drives for a thorough test. Only, now I can ONLY boot up if I DO NOT have the missing drive plugged in. This is really weird. If I have all three devices attached then it claims that 2/3 of the devices that make up md2 (my root) are unavailable and well then we are screwed. WTF?
Anyway, here's my setup, let me know what else you need to know:
/boot /dev/md0 RAID1 (/dev/sda1 /dev/sdb1 /dev/sdc1)
swap /dev/md1 RAID1 (/dev/sda2 /dev/sdb2 /dev/sdc2)
/ /dev/md2 RAID5 (/dev/sda3 /dev/sdb3 /dev/sdc3)
/home /dev/md3 RAID5 (/dev/sda5 /dev/sdb5 /dev/sdc5)
/var /dev/md4 RAID5 (/dev/sda6 /dev/sdb6 /dev/sdc6)
The drive that is currently "failed" is /dev/sdb. Again, the system boots up happily with sdb disconnected. But has fits if it is reconnected and all 3 drives are connected.
All help is appreciated,
Ken Causey
Quoted 16 lines · On June 26, [email protected] wrote:
Hi,
Interesting problem. I'm setting up an all software RAID system and after a few fits and starts have reached some success. I started to do some testing and have run into a problem. What I was doing is I was one by one unplugging one of the SCSI drives and then powering up the system to make sure it would power up properly. The first time I did this everything worked great. I plugged the drive back up and used raidhotadd to recover and got everything to UUU. I then powered off and unplugged another drive, system boots up great with only two drives. Now its time to plug the drive back in and rebuild the array to be ready to unplug the last of the three drives for a thorough test. Only, now I can ONLY boot up if I DO NOT have the missing drive plugged in. This is really weird. If I have all three devices attached then it claims that 2/3 of the devices that make up md2 (my root) are unavailable and well then we are screwed. WTF?
Let me guess... you are using "raidstart" to start the arrays?
If so, that is your problem. It is broken.
Either change the partition type to use auto-detect, or use mdadm:
http://www.cse.unsw.edu.au/~neilb/source/mdadm/
If you aren't using raidstart, tell me and I try harder.
NeilBrown
Quoted 18 lines · Neil Brown
Quoted 16 lines · On June 26, [email protected] wrote:
Hi,
Interesting problem. I'm setting up an all software RAID system and after a few fits and starts have reached some success. I started to do some testing and have run into a problem. What I was doing is I was one by one unplugging one of the SCSI drives and then powering up the system to make sure it would power up properly. The first time I did this everything worked great. I plugged the drive back up and used raidhotadd to recover and got everything to UUU. I then powered off and unplugged another drive, system boots up great with only two drives. Now its time to plug the drive back in and rebuild the array to be ready to unplug the last of the three drives for a thorough test. Only, now I can ONLY boot up if I DO NOT have the missing drive plugged in. This is really weird. If I have all three devices attached then it claims that 2/3 of the devices that make up md2 (my root) are unavailable and well then we are screwed. WTF?
Quoted 1 line
Let me guess... you are using "raidstart" to start the arrays?
Exactly.
Quoted 1 line
If so, that is your problem. It is broken.
Ok. Good to know.
Quoted 4 lines
Either change the partition type to use auto-detect, or use mdadm:
http://www.cse.unsw.edu.au/~neilb/source/mdadm/
mdadm it will have to be. I'm using an initrd kernel and autodetection is very specifically removed in the raid modules.
Quoted 1 line
If you aren't using raidstart, tell me and I try harder.
This is a very good start and I suspect it will fix me. Now if only mkinitrd would use mdadm automatically rather than raidstart... Oh well, that's a battle for another day.
Ken Causey
Quoted 3 lines
NeilBrown