LinuxQuestions.org
Review your favorite Linux distribution.
Go Back   LinuxQuestions.org > Forums > Linux Forums > Linux - Newbie
User Name
Password
Linux - Newbie This Linux forum is for members that are new to Linux.
Just starting out and have a question? If it is not in the man pages or the how-to's this is the place!

Notices


Reply
  Search this Thread
Old 02-03-2013, 06:39 AM   #1
alieblice
Member
 
Registered: Jul 2011
Posts: 80

Rep: Reputation: Disabled
recovering raid 5


hi
i was playing with mdadm command to learn setting up raid on linux so i did this

i setted up a raid 5 on vmware (virtual Debian 6 )with 3 disks /dev/sdb /dev/sdc /dev/sdd
and it was working fine . then i ran these 2 commands to see what happens

Code:
mdadm /dev/md0 --fail /dev/sdb
mdadm /dev/md0 --fail /dev/sdc
after that i restarted the virtual machine.
and when the system booted there was no raid like there wasn't any raid .

so i was thinking is it possible to recover the raid since there wasn't a real failure .
 
Old 02-03-2013, 07:16 PM   #2
chrism01
LQ Guru
 
Registered: Aug 2004
Location: Sydney
Distribution: Centos 6.8, Centos 5.10
Posts: 17,240

Rep: Reputation: 2324Reputation: 2324Reputation: 2324Reputation: 2324Reputation: 2324Reputation: 2324Reputation: 2324Reputation: 2324Reputation: 2324Reputation: 2324Reputation: 2324
RAID5 can only handle ONE disk failure; you need RAID6 for 2 disk failures.
https://en.wikipedia.org/wiki/Standard_RAID_levels
https://en.wikipedia.org/wiki/RAID
http://linux.die.net/man/8/mdadm

You can try to use the --remove option, then re-add them back, using the force option also.
(see 3rd link)
In a real system, you'd better have a backup first....
 
Old 02-04-2013, 05:57 AM   #3
alieblice
Member
 
Registered: Jul 2011
Posts: 80

Original Poster
Rep: Reputation: Disabled
thanks for replying .

I used this tutorial and i was able to recover it easily.
https://raid.wiki.kernel.org/index.php/RAID_Recovery

I'm steel newbie to raid is tacking backup from output of this command enough ?
Code:
# mdadm --detail /dev/md0
 
Old 02-04-2013, 07:58 AM   #4
chrism01
LQ Guru
 
Registered: Aug 2004
Location: Sydney
Distribution: Centos 6.8, Centos 5.10
Posts: 17,240

Rep: Reputation: 2324Reputation: 2324Reputation: 2324Reputation: 2324Reputation: 2324Reputation: 2324Reputation: 2324Reputation: 2324Reputation: 2324Reputation: 2324Reputation: 2324
I was talking about backing up the data stored on the RAID array; that just shows the RAID structure.
 
  


Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off



Similar Threads
Thread Thread Starter Forum Replies Last Post
RAID 1 Failure - Recovering krazybob Linux - Hardware 2 12-12-2012 12:54 AM
Recovering Raid 1 disk astroboy771 Linux - Software 0 06-17-2012 05:50 AM
Recovering software 5 RAID wesleywest Red Hat 1 02-09-2005 03:35 PM
recovering data from an old RAID -0 dominant Linux - Software 1 01-26-2005 03:42 AM
Recovering Software RAID Mirror rootking Linux - Software 1 11-01-2004 08:32 PM


All times are GMT -5. The time now is 08:54 PM.

Main Menu
Advertisement
My LQ
Write for LQ
LinuxQuestions.org is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
Syndicate
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration