How to start broken Linux Software RAID ?


May i know how to start broken linux software raid ?

I have the following :

[root@vps-svr1 ~]# cat /proc/mdstat
Personalities : [raid1]
md0 : active raid1 sdb1[1] sda1[0]
      200704 blocks [2/2] [UU]

md1 : active raid1 sdb3[1] sda3[0]
      2048192 blocks [2/2] [UU]

md3 : active raid1 sdb5[1]
      473845056 blocks [2/1] [_U]

md2 : active raid1 sdb2[1] sda2[2](F)
      12289600 blocks [2/1] [_U]

unused devices: <none>
[root@vps-svr1 ~]#

I have tried the following but no luck ?

[root@vps-svr1 ~]# mdadm --manage /dev/md3 --fail /dev/sdb5
mdadm: set /dev/sdb5 faulty in /dev/md3
[root@vps-svr1 ~]#

[root@vps-svr1 ~]# mdadm --manage /dev/md3 --remove /dev/sdb5
mdadm: hot remove failed for /dev/sdb5: Device or resource busy
[root@vps-svr1 ~]#

[root@vps-svr1 ~]# mdadm --manage --stop /dev/md3
mdadm: fail to stop array /dev/md3: Device or resource busy
[root@vps-svr1 ~]#

[root@vps-svr1 ~]# mdadm --add /dev/md3 /dev/sdb5
mdadm: Cannot open /dev/sdb5: Device or resource busy
[root@vps-svr1 ~]

Appreciates if anybody can provide a step by step on how to update/start the raid.

Thank you.

Shamsul KamalJunior TechAsked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Hmm I did this not long ago with a RAID 5 array....

If i can remember properly, I just force started the array with the 2 drives and then added the 3rd after...

I think the command your looking for is:

mdadm --manage --run /dev/md3 /dev/sdb5


mdadm --manage /dev/md3 --add /dev/sdXX

give that a shot...

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
Shamsul KamalJunior TechAuthor Commented:

I've tried that but no luck, the following is the result :

[root@vps-svr1 ~]# mdadm --manage --run /dev/md3 /dev/sdb5
mdadm: internal error - devmode[/dev/sdb5]=0
[root@vps-svr1 ~]# mdadm --manage /dev/md3 --add /dev/sdb5
mdadm: Cannot open /dev/sdb5: Device or resource busy
[root@vps-svr1 ~]#
"mdadm: Cannot open /dev/sdb5: Device or resource busy"

Same error I was getting for a bit...

Hmm what do you get when you type:

# mdadm --detail /dev/md3

The Ultimate Tool Kit for Technolgy Solution Provi

Broken down into practical pointers and step-by-step instructions, the IT Service Excellence Tool Kit delivers expert advice for technology solution providers. Get your free copy for valuable how-to assets including sample agreements, checklists, flowcharts, and more!

Shamsul KamalJunior TechAuthor Commented:

I managed to rebuild using "mdadm --manage /dev/md3 --add /dev/sda5"

It seems the active raid was sdb5 , i gues that is why the first command did't work.
Ahh... Well, glad to hear its back up.
Shamsul KamalJunior TechAuthor Commented:
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today

From novice to tech pro — start learning today.