Learn how to a build a cloud-first strategyRegister Now


Replace failed RAID drive

Posted on 2008-11-03
Medium Priority
Last Modified: 2016-12-08
I have an old Redhat box running RAID 5. One of the drives failed and needs to be replaced.

I found instruction below on how to replace it but the instructions leave a few questions unanswered.

"3. Partition the new drive so that the partitions on it are identical to those on the other drive(s) in the array"
How do I do that?

"4. Issue the following command: raidhotadd <raid-device> <disk-partition>"
How do I find out what <raid-device> is and what <disk-partition> is?

Thanks. Rebuilding a RAID array with raidhotadd
Should /proc/mdstat show that a problem exists with one of the RAID arrays, the raidhotadd
utility program should be used to rebuild the array. Here are the steps that would need to be performed:
1. Determine which disk drive contains the failed partition
2. Correct the problem that caused the failure (most likely by replacing the drive)
3. Partition the new drive so that the partitions on it are identical to those on the other drive(s) in the array
4. Issue the following command:
raidhotadd <raid-device> <disk-partition>
5. Monitor /proc/mdstat to watch the rebuild take place. Here is a command that can be used to watch the rebuild as it takes place:
watch -n1 cat /proc/mdstat

Open in new window

Question by:xy8088
  • 2
LVL 43

Expert Comment

ID: 22869328
Hmm, I usually do
sfdisk -d /dev/currentMember | sfdisk /dev/newMember
before You ask how You find current and new member refer next question

cat /proc/mdstat # shows all software raids on Your system with members, pick the correct one (is should has failed disks).

You can bring the content here so we'll try figure it out for You.

Author Comment

ID: 22876900
Running "cat /proc/mdstat" gives me:

Personalities :
read_ahead not set
unused devices: <none>
LVL 43

Accepted Solution

ravenpl earned 2000 total points
ID: 22877024
Since You have no software raids defined, I suspect You have hardware raid implemented on the HW controller. Refer controller's guide then.

Featured Post

What does it mean to be "Always On"?

Is your cloud always on? With an Always On cloud you won't have to worry about downtime for maintenance or software application code updates, ensuring that your bottom line isn't affected.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Linux users are sometimes dumbfounded by the severe lack of documentation on a topic. Sometimes, the documentation is copious, but other times, you end up with some obscure "it varies depending on your distribution" over and over when searching for …
The purpose of this article is to demonstrate how we can upgrade Python from version 2.7.6 to Python 2.7.10 on the Linux Mint operating system. I am using an Oracle Virtual Box where I have installed Linux Mint operating system version 17.2. Once yo…
Learn how to find files with the shell using the find and locate commands. Use locate to find a needle in a haystack.: With locate, check if the file still exists.: Use find to get the actual location of the file.:
Get a first impression of how PRTG looks and learn how it works.   This video is a short introduction to PRTG, as an initial overview or as a quick start for new PRTG users.
Suggested Courses
Course of the Month21 days, 2 hours left to enroll

810 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question