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16
votes
2answers
31k views

How to recover a crashed Linux md RAID5 array?

Some time ago I had a RAID5 system at home. One of the 4 disks failed but after removing and putting it back it seemed to be OK so I started a resync. When it finished I realized, to my horror, that 3 ...
6
votes
2answers
1k views

Will the system make sure that mdadm is sync-ed before completing a reboot?

This is a follow up to my crazy mdadm problem. I'm trying to figure out what might have caused sda to get out of sync in the first place. The only thing I can think of is that I had just run a bunch ...
3
votes
3answers
270 views

How to safely replace a not-yet-failed disk in a Linux RAID5 array?

I have a software RAID5 array (Linux md) on 4 disks. I would like to replace one of the disks with a new one, without putting the array in a degraded state, and if possible, online. How would that ...
6
votes
2answers
5k views

How to raid-mirror existing root partition?

I'd like to mirror my existing root (and only) partition on an SSD to another disk. It should be a sort of RAID-1, just asymmetric*. I know there's the option mdadm --write-behind, which should do it. ...
10
votes
4answers
6k views

Linux - Repairing bad blocks on a RAID1 array with GPT

The tl;dr: how would I go about fixing a bad block on 1 disk in a RAID1 array? But please read this whole thing for what I've tried already and possible errors in my methods. I've tried to be as ...
5
votes
1answer
9k views

mdadm raid1 and what chunksize (or blocksize) on 4k drives?

I want to use two 3 TB drives in a mdadm raid1 setup (using Debian Sequeeze). The drives use 4k hardware sectors instead of the traditional 512 byte ones. I am a bit confused because on the one hand ...
2
votes
1answer
342 views

Drive was unable to assemble into the array

I ran mdadm -A /dev/md0 /dev/sda1 /dev/sdb1 Only /dev/sdb1 was loaded into the array though. I have a few more arrays on the same two drives too. Each time the partition on sda failed. dmesg told ...
3
votes
2answers
958 views

What does mdadm's “spare” number mean?

I created a mdadm-based RAID 5 from six hard drives using the following command: # mdadm --create /dev/md0 --level=5 --raid-devices=5 \ /dev/sdb1 /dev/sdc1 /dev/sdd1 /dev/sde1 /dev/sdf1 \ ...
3
votes
2answers
5k views

Does Grub2 support putting /boot on a RAID5 partition?

It looks like currently most OS installers insist on putting /boot on a non-RAID partition (or the kind of RAID1 partition that "looks like" a non-RAID partition), even the installers that support ...
1
vote
2answers
243 views

Copying linux install from non-RAID/x86 to RAID/x86-64

I'm copying an Ubuntu Server install from an x86 machine with a single hard disk to a new machine with x64 and two identical disks. Two partitions will span the new disks: One small-ish RAID1 for ...
0
votes
2answers
246 views

Migrate an entire volume group LVM2 to RAID5

I have a Virtual Host server build with Ubuntu and Xen SO Ubuntu 12.04.1 LTS 64Bits xen-hypervisor-4.1 Disk Hitachi SAS 15K 147GB (x2) in a Volume group sda1 1GB /boot sda2 146GB lvm sdb1 ...