A linux utility used to manage software RAID devices.

learn more… | top users | synonyms

4
votes
1answer
364 views

3 drives fell out of Raid6 mdadm - rebuilding?

i had an mdadm raid6 array with 13x1TB drives. Within 10 minutes 3 of these drives fell out of the array... we assume bad cable to the controller card and replaced, however now we need to get the ...
4
votes
1answer
436 views

Debian installation on software RAID (lilo.conf configuration)

Debian installation program has created lilo.conf: boot=/dev/md1 root=/dev/md1 raid-extra-boot=mbr-only But when i configure lilo i usually put these lines disk=/dev/md1 sectors=63 heads=255 ...
4
votes
2answers
3k views

Failed MDADM Array With Ext.4 Partition - “e2fsck: unable to set superblock flags on /dev/md0”

Had a power failure and now my mdadm array is having problems. sudo mdadm -D /dev/md0 [hodge@hodge-fs ~]$ sudo mdadm -D /dev/md0 /dev/md0: Version : 0.90 Creation Time : Sun ...
4
votes
1answer
492 views

EC2 disk goes to 100% util, but fine after reboot

We've been running some production services on Amazon EC2 for a while, using mainly t1.large and t1.xlarge instances (non-EBS). Every so often one of the attached (ephemeral disks) will get into a ...
3
votes
2answers
776 views

Mdadm won't create an array larger than 10TB

I have a server with six 4TB drives running Ubuntu 14.04 LTS. One of the drives is used for the system/OS I wanted to use the other 5 drives to get as close to 20TB of storage as possible It's a ...
3
votes
2answers
20k views

How do I get mdadm to auto assemble my raid array?

After upgrading to Ubuntu 9.04, my raid 5 array is no longer being assembled correctly. Right now, from boot, it will start a raid array using ata-MAXTOR_STM3500630AS_9QG03T0L-part1, at /dev/md0, but ...
3
votes
3answers
292 views

Degraded partition in RAID5 system

I've got a server running Debian Squeeze and a 3x 500 GB-drive RAID5 system which I haven't set up myself. When booting, the status of one partition in the RAID-array seems to be bad. md: ...
3
votes
1answer
540 views

mdadm RAID1 to RAID6

I've got a RAID1 array. I'm buying 4 more disks of equal size (they're the same model drives) and I'm trying to enumerate my options for a safe upgrade. Ideally they'll be one large ext3 volume. ...
3
votes
1answer
276 views

Does growing a RAID 5 destroy the data on the RAID?

For a linux software RAID using madadm, does adding a harddrive and growing onto the RAID, destroy the data that's already on the RAID or does it preserve everything?
3
votes
2answers
1k views

Raid 5 with 4 disks on Debian automatically creates a spare drive

I'm trying to to create a RAID 5 with 4x 2TB disks on Debian 6. I followed the instructions from: http://zackreed.me/articles/38-software-raid-5-in-debian-with-mdadm I created the raid with following ...
3
votes
1answer
831 views

Growing a RAID5 using mdadm with multiple drives?

I have a RAID5 array that consists of 3, 2TB drives. I want to add 2 more drives. The tutorials involve adding a single drive to an array, such as this: https://raid.wiki.kernel.org/index.php/Growing ...
3
votes
3answers
1k views

Is mdadm Raid-1 Over A Network File Share Possible?

I am using 64bit CentOS 5.5 I know it's possible to set up software RAID1 using mdadm using a physical hard disk and a RAM disk. Is it possible to set up software RAID1 with mdadm using a NFS mount ...
3
votes
6answers
4k views

Recover RAID-5 that was already running in degraded mode (lost a second disk)

this is silly, this has happened before and I figured out how to fix it and it was fine. I'm running 4 500GB SATA drives in a RAID-5 on Ubuntu 7.10 server. One of the disks failed (actually I think ...
3
votes
2answers
567 views

Linux Software RAID1 Rebuild Completes, but after reboot, its degraded again

I have been beating my head with an issue here, and I'm now turning to the internet for help. I have a system running Mandrake Linux, with the following configuration: /dev/hda - This is a IDE ...
3
votes
2answers
339 views

Reading off of MDADM drives after server died

I had a 2-drive RAID-1 array running on ubuntu, which I had forgotten about. The host I was running them on is now dead, leaving me with these two disks. How can I get data off of them? If I dump ...
3
votes
1answer
281 views

reshaping raid and growing raid

This is a two part question. 1) Can you reshape raid 5 to 6 with mdadm on linux (fairly sure you can, but cant get mdadm to accept it) 2) Can you do 1) while also growing the array in one go ?
3
votes
3answers
555 views

What are the advantages and disadvantages of constructing an mdam array from whole disks vs. partitions?

Let's say I've got six identical drives and I'm going to use them all in a RAID10,f2 array constructed using mdadm. I've always put a single partition on each disk and constructed the array from ...
3
votes
1answer
464 views

Software RAID1 ready to fail - How can I degrade manually?

I have a Centos 5.4 server in production with 2 drives in software RAID1. The last days /var/log/messages has a lot of messages, showing that one of the drives is ready to fail: Sep 23 00:48:38 ...
3
votes
2answers
832 views

How to diagnose intermittently slow raid data transfer rate?

I have an encrypted RAID6 set up on Centos 5.5. When I transfer a large 10gb file from the raid to my computer it will pause at around 4-5gb and again at 9gb. The data transfer drops from 25mb/sec to ...
3
votes
1answer
3k views

Linux Mdadm + LVM recovery

I recently reinstalled my Ubuntu server with 10.04, and am having trouble reactivating the LVM partition which houses all my non-critical data. /dev/sda, /dev/sdb, /dev/sdc, and /dev/sdd are all ...
3
votes
1answer
27 views

Reading /proc/mdstat

I just built my first raid5 yesterday (with 4 hds) and was reading about monitoring with /proc/mdstat. My understanding is an ideal dispaly with 4 drives should be [UUUU] however mine reads [UUU_]. ...
3
votes
3answers
721 views

Slow disk I/O in KVM with LVM and md raid5

I have been battling with a kvm setup under debian for two weeks now, specifically with guest I/O disk performance. The system: -Supermicro 1018d-73mtf (X10SL7-F motherboard) -16GB ECC/UB -Intel ...
3
votes
1answer
1k views

How do you set up RAID1 with both disks bootable on Debian/Ubuntu?

In Debian 6, new installation, what is the recommended way of setting up a software RAID1 array so that the system is bootable from both disks? I have heard that people that don't know what they are ...
3
votes
1answer
584 views

Removing a device in “removed” state from Linux software RAID array

My workstation has two disks(/dev/sd[ab]), both with similar partitioning. /dev/sdb failed, and cat /proc/mdstat stopped showing the second sdb partition. I ran mdadm --fail and mdadm --remove for ...
3
votes
1answer
306 views

mdadm kernel log messages explained

Welcome. I try to recover from linux software raid failure. I am in a process of recreating the superblocks based on a syslog from the system when it was healthy. The log speaks about 2 md devices, ...
3
votes
1answer
2k views

Linux raid controller (LVM/MDADM)

Today I'm in a very bad place. A production raid array went down. The controller failed. After unmounting the file systems and killing all processes, I changed the hardware controller. On restarting ...
3
votes
1answer
868 views

Unresponsive mdadm

I have a raid 5 mdadm raid array set up with 6 drives and a hot spare on an Ubuntu 11 server. There are a couple samba shares on the drive, and until today, they were working well. A couple hours ago ...
3
votes
2answers
1k views

Odd mdadm output: --examine shows array state failed, --detail shows everything clean

The setup: 8 disks in a mdadm-managed RAID5 array (/dev/md0, made from /dev/sdc through /dev/sdj). One disk (/dev/sdh) is showing SMART errors (increasing pending sector count) so I'm looking to ...
3
votes
3answers
1k views

ext3 format options

I'm creating a ext3 filesystem on top of a software raid5 (md) and I'm wondering what are the best parameters when creating the filesystem (with mkfs.ext3) and while mounting. RAID5 chunk size is ...
3
votes
1answer
668 views

Linux RAID mdadm: what does 'Events' mean?

When I type mdadm --detail /dev/md0 I get a lots of useful information most of which I understand. However I also get a line that reads: Events : 0.710 Where the number varies. Naively, I ...
3
votes
1answer
463 views

reliably and automatically determine connection path of physical position of HDD from /dev/sdX device file

This is kind of a FAQ, but all the answers I found so far are not suited for full automation, which is what I need. So here it goes again. In Linux: Is there a reliable way to resolve the udev ...
3
votes
3answers
2k views

Why is my mdadm raid-1 recovery so slow?

On a system I'm running Ubuntu 10.04. My raid-1 restore started out fast but quickly became ridiculously slow (at this rate the restore will take 150 days!): dimmer@paimon:~$ cat /proc/mdstat ...
3
votes
1answer
192 views

mdadm raid6 recovery reads more from one drive?

I just replaced a fault drive in my raid6-array (consisting of 8 drives) during the recovery I did notice something strange in iostat. All drives are getting the same speeds (as expected) except for ...
3
votes
1answer
265 views

Putting a spare Raid device back to active state

I have a problem with my Raid setup. I have 3 disks in my Raid: md2 : active raid5 sdc3[3](S) sdb3[4](S) sda3[0] 2925532672 blocks level 5, 64k chunk, algorithm 2 [3/1] [U__] md1 : active ...
3
votes
1answer
100 views

RAID-5 array being split on reboot (ubuntu)

I've set up a RAID-5 array on Ubuntu 13.04 (kernel 3.8.0-27-generic) using mdadm - v3.2.5 - 18th May 2012. It appears to work fine and be in high spirits: $ cat /proc/mdstat Personalities : ...
3
votes
1answer
158 views

MDADM Rebuilding

I'm currently rebuilding a RAID6 MDADM array from 5 devices to 9. cat /proc/mdstat: Personalities : [raid6] [raid5] [raid4] md0 : active raid6 sde1[0] sdg1[9](F) sdh1[8](F) sdi1[6](F) sdj1[7](F) ...
3
votes
1answer
145 views

How to get rid of a stubborn 'removed' device in mdadm

One of my server's drives failed and so I removed the failed drive from all three relevant arrays, had the drive swapped out, and then added the new drive to the arrays. Two of the arrays worked ...
3
votes
1answer
576 views

flashcache with mdadm and LVM

I am having trouble setting up flashcache on a system with LVM and mdadm, I suspect I am either just missing an obvious step or getting some mapping wrong and hoped someone could point me in the right ...
3
votes
2answers
879 views

Is it safe to interrupt a mdadm --grow operation?

I recently changed the disks in my RAID5 from 3x2TB to 3x3TB. I also wanted to change the chunk size from default 512k to 128k. I have added all new devices to the array and I run: mdadm /dev/md1 ...
3
votes
1answer
571 views

Resize openSUSE 12.3 GPT ext4 partitions in a RAID1 disk array

I have a software raid configured (/dev/md2) which has assigned the partitions sda3 and sdb3 from two 3TB disks (sda and sdb). The partition types are GPT not LVM and file system is ext4. Now, the ...
3
votes
1answer
222 views

Cannot get at data in my NAS

I've got a bit of an issue that I'm hoping you can help me with. I have an Iomega ix4 as my NAS. This runs Linux and each drive in the box has 2 partitions: one for the OS and RAID info, and the ...
2
votes
3answers
2k views

How to undo an mdadm RAID 1 without losing data

I have a two disk, RAID 1 set up from mdadm. Long story short, turns out this server has an actual RAID controller, so a hardware raid would be more preferable than the software raid. In addition, the ...
2
votes
2answers
124 views

Linux RAID 1: How to make a secondary HD boot?

I have the following RAID 1 on a Centos 6.5 server: # cat /proc/mdstat Personalities : [raid1] md0 : active raid1 sdb1[3] 974713720 blocks super 1.0 [2/1] [_U] bitmap: 7/8 pages [28KB], ...
2
votes
1answer
2k views

Why does MDADM Raid 5 require a spare

From the mdadm man page: "When creating a RAID5 array, mdadm will automatically create a degraded array with an extra spare drive. This is because building the spare into a degraded array is in ...
2
votes
3answers
148 views

mdadm - Remove disk from RAID0

So, I'd like to know, is is possible to do the following with mdadm: I start with RAID0 configuration on 2 disks: sda and sdb. I would like to add one more disk to array, sdc and move all data from ...
2
votes
3answers
931 views

Can I convert a raid10 array to raid0?

I have created a raid10 array using mdadm. Metadata version is 1.2. I want to convert this to a raid0 array, is it possible? P.S. I am having terabytes of data, I want to avoid copying the data over. ...
2
votes
3answers
259 views

What happen when you replace a broken harddrive with a bigger one into RAID5

Given I have a raid 5 of /dev/sda, dev/sdb, /dev/sdc, now with the same size (said 250G) But later, /dev/sda failed, so I replaced it with /dev/sdd of 500G. What happens? If Later I replace /dev/sdb ...
2
votes
7answers
8k views

What tells initramfs or the Ubuntu Server boot process how to assemble RAID arrays?

The simple question: how does initramfs know how to assemble mdadm RAID arrays at startup? My problem: I boot my server and get: Gave up waiting for root device. ALERT! /dev/disk/by-uuid/[UUID] does ...
2
votes
5answers
390 views

Future proof RAID-like storage solution in Linux

I'm currently running my storage server on 4x1TB disks in RAID5. There are no issues here, no lack of speed, no lack of performance. But now these disks are getting out of free space and I have the ...
2
votes
5answers
467 views

RAID level 1 of 2 Network Block Devices

I currently have a RAID level 1 of 2 500 GB HDs. The RAID is managed by server 1 and the drives are in 2 different servers. The RAID works great once I get it setup, however, at random times the ...