A linux utility used to manage software RAID devices.

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How to recover an mdadm array on Synology NAS with drive in “E” state?

Synology has a customized version the md driver and mdadm toolsets that adds a 'DriveError' flag to the rdev->flags structure in the kernel. Net effect - if you are unfortunate enough to get a array ...
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96 views

mdadm array fails to start at boot, bad superblock on component drive

At boot my mdadm raid5 array fails to start, saying that one of my disks (sdi) has a bad superblock. However, once I log in, I can start the array no problem with mdadm --assemble /dev/md0 ...
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252 views

grub on debian wheezy doesn't recognise mdraid

We're having a really strange problem when trying to boot from an mdraid on Debian Wheezy. All references online that I can find tell me that grub 1.99 (which is part of Debian Wheezy) should have no ...
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92 views

expanded 8 drive RAID 6 fails to assemble in new server, 5 original devices show no md superblock

I am in desperate need of you help. Neil Brown does fantastic work, and I have relied on mdadm for years to run very stable server systems, never had major problems I could not solve. This time its ...
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2answers
181 views

How do I fix my server to boot properly after removing / adding a drive on my mdadm software RAID

I configured a RAID-5 array for a data partition mounted on /mnt/data. My system is not booting on it (/ and /boot is on a dedicated drive not part of any RAID array). I added a 4th drive to my 3 ...
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126 views

mdadm raid10 or nfs performance issues?

I have a fresh mdadm RAID10 device which is healthy, built from 4 x 7200rpm SATA 3 drives: # cat /proc/mdstat Personalities : [raid10] [raid1] md2 : active raid10 sdc3[5] sda3[4] sdb3[1] sdd3[3] ...
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1answer
74 views

Drawbacks with smaller fdisk partitions, mdadm RAID10, LVM and KVM?

I am setting up a new virtualized server with KVM and LVM. The KVM host and all guests will be installed on a SSD drive. Each guest will have access to a RAID10 array made of 4x3TB sata drives, used ...
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188 views

mdadm error: found two disks with the number 0

Im running a server deep in the forest , and after a hard disco failure i got this error. error: found two disks with the number 0. It a server with 2, 1 TB disc in raid 1 with mdadm 0.9 SDA failed ...
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1answer
34 views

MDADM RAID5 Size

I currently have 9x1TB disks in RAID5, which to me is 8TB worth of storage. However, I am not getting that at all. This was after moving from RAID6 to RAID5 and performing the necessary commands to ...
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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 : ...
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28 views

mdadm confused on minor number

Recently replaced a faulty disk in my Raid 6 group. All went as expected, no problem. After getting everything rebuilt using a new /dev/sdi1 as a replacement for the failing /dev/sde1 I decided to ...
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199 views

Restore LVM if VG is not consistent (XenServer 5.6.1)

i have a VG that uses the PVs /dev/md1 and /dev/md2. Now one hdd failed in /dev/md1: [root@xenserver1 ~]# cat /proc/mdstat Personalities : [raid1] md1 : active raid1 sda3[0] 382320128 blocks ...
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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) ...
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3answers
724 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 ...
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21 views

Harddrive check going-on?

I have a server that has suddenly become unusable (responds very slowly to requests). It seems to be related to some on-going RAID check. Here is what I get when I run cat /proc/mdstat : ...
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2answers
123 views

Recommended solution to join partitions (disks) into single partition [closed]

I have 4 hard disks (1 Tb each) on server. It's debian wheezy, amd64. Disks 2,3 and 4 are not partitioned yet. I have to join them into single partition, it must be single filesystem/mountpoint for ...
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2answers
81 views

Check health of RAID array

I have a server with RAID 1. Currently when I type in the following command: cat /proc/mdstat I get: Personalities : [linear] [raid0] [raid1] [raid10] [raid6] [raid5] [raid4] [multipath] [faulty] ...
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1answer
177 views

Is it safe to snapshot an mdadm RAID with only xfs_freeze?

Is mdadm guaranteed (and trusted via experience) to be safe for taking snapshots with only an xfs_freeze? I have encountered vague warnings about mdadm still working in the background, thus making ...
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1answer
30 views

mdadm grow operation giving nonstop libata errors

Running Debian 7, mdadm 3.2.5. I issued a command to grow a 5 disk, 3 spare raid 5 array to an 8 disk, 0 spare raid 6 array: mdadm --grow /dev/md0 --level=6 --raid-devices=8 ...
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1answer
302 views

How to delete removed devices from a mdadm RAID1?

I had to replace two hard drives in my RAID1. After adding the two new partitions the old ones are still showing up as removed while the new ones are only added as spare. I've had no luck removing the ...
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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 ...
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1answer
579 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 ...
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2answers
133 views

Path of md device wrong after reboot

I have to set up a software raid (level1) on a Ubuntu server 12.04. It should serve files in the network via Samba. The server has the following disks: 250gb Sata hdd (Ubuntu is installed on that ...
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2answers
88 views

Linux: How to restore data from failed disk from software raid

I have a disk failure in software RAID (1) and marked a broken disk as fault (mdadm --manage /dev/md0 --fail /dev/sda1). Unfortunately I destroyed data on the second disk after that. Is it possible to ...
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1answer
184 views

linux raid 1: right after replacing and syncing one drive, the other disk fails - understanding what is going on with mdstat/mdadm

We have an old RAID 1 Linux server (Ubuntu Lucid 10.04), with four partitions. A few days ago /dev/sdb failed, and today we noticed /dev/sda had pre-failure ominous SMART signs (~4000 reallocated ...
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41 views

Software (md) raid does not reuse new drive

I have software raid6 array, which failed today. I've removed failed disk. Here is status: /dev/md0: Version : 1.2 Creation Time : Sun Nov 4 04:26:03 2012 Raid Level : raid6 ...
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1answer
105 views

Expanding raid 5 luks partition

I have just bought 2 new drives to my raid 5 array. I have successfully added them to the array and resynced. I now have a /dev/md4 drive that is 16 TB, but the crypt-luks partition md4p1 is still 12 ...
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76 views

Replace a slowly dying drive in Linux software raid5

I have the same problem as in Can I "atomically" swap a raid5 drive in Linux software raid? i.e. a Linux software raid with 3 RAID5 disks where one disk is showing smart errors but isn't ...
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564 views

Fedora, fsck fails at boot

I'm facing a problem in my server during the startup. This is my actual configuration: 320GB each. Raid1 -> /dev/md127. Working. /dev/sda /dev/sdc 1000GB each. Raid1 -> Use to be /dev/md126, ...
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78 views

What is the correct way to create new raid5 in Linux?

I added some new disks, and tried to create new array, using: mdadm --create /dev/md/2 --level=5 -x 0 --raid-devices=4/dev/sd{a,b,c,g}2 It creates the array, but after reboot - it's gone. What ...
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145 views

Convert Raid 1 to Raid 10 with no new disks

I just got a new remote root-access server with 2 1TB disks in a Raid 1 configuration, running Debian (squeeze). Before installing my stuff on it, I'd like to switch to Raid 10 if I can. All the ...
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176 views

syncing mdadm event count

I had a disk die in my level 5 RAID and before I could replace it, my RAID crapped out while I was copying some data onto it. Reading the RAID kernel wiki on RAID recovery I've tried forcing an ...
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1k views

mdadm raid5 recover double disk failure - with a twist (drive order)

Let me acknowledge first off that I have made mistakes, and that I have a backup for most but not all of the data on this RAID. I still have hope of recovering the rest of the data. I don't have the ...
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2answers
177 views

M1015 pass-through and hot-swap in Linux with md raid (IBM x3620)

I'm setting up a small, but hopefully durable server for a student community, and the hardware is an IBM x3620 M3 with a builtin M1015 RAID card. To make the setup future proof and avoid vendor ...
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1answer
726 views

RAID Recovery on a QNAP TS-869U-RP

I've had my trusty QNAP NAS (T869-RU) fail on me over night with (apparently) two of the eight disks in the RAID5 MDADM array from /proc/mdstat: [/etc] # cat /proc/mdstat Personalities : [linear] ...
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1answer
222 views

Currently unreadable sectors on RAID 5 linux drive

I have every 30 minutes smartd messages on /var/log/messages: smartd[3588]: Device: /dev/sdc, 176 Currently unreadable (pending) sectors This drive (sdc) is part of RAID 5 configured with mdadm. ...
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1answer
365 views

How do I check if smartd and mdadm are running correctly?

I have a raid system on debian: Disk /dev/sda: 320.1 GB,... Device Boot Start End Blocks Id System /dev/sda1 * 1 2432 19535008+ fd Linux raid ...
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2answers
1k views

mdadm --zero-superblock on disks with other partitions on them

I have three disks which used to hold an MD RAID5 array. I have since removed (or so I thought) this array and created partions for btrfs and swap space. On rebooting the machine, MD still binds the ...
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146 views

How to disable MD RAID or prevent degraded arrays from starting. (Centos 6.4)

I am trying to disable software RAID at boot time. My ultimate goal is to prevent the system from starting raid arrays that are in a degraded state. rd_NO_MD is present on the kernel command line by ...
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2answers
304 views

Remake SW RAID1 from a new HDD and an old HDD with bad blocks

I have a SW RAID1 and I just replaced /dev/sda with a new HDD as the old one failed. Now, upon trying to recreate the RAID array I discovered that the "good" HDD (/dev/sdb) has bad blocks with prevent ...
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1answer
138 views

Saving data on a failing software RAID 1 setup

My CentOS 6 server is running a software RAID 1 configuration with two 1 TB disks. Yesterday trouble started happening when the server was very irresponsive. I checked the logs and noticed a whole ...
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1answer
179 views

Rebuild mdadm RAID5 array with fewer disks

I have a 4 disk RAID5 array, one of which is starting to fail according to smartd. However, since I'm using less than half the space on /dev/md0, I'd like to rebuild the array without the failing ...
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1answer
100 views

Re-mount EBS vol on EC2 instance

I am new to sysadmin. I am trying to launch a EBS-backed EC2 instance. I did the following based on mongodb docs: sudo mdadm --verbose --create /dev/md0 --level=10 --chunk=256 --raid-devices=1 ...
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1answer
731 views

Linux - dmraid (or mdadm) - Rebuild RAID 10

A while ago I had a raid10 config crap out on me, and am now just getting around to trying to salvage the array so I can rebuild and move on with my life. Basically a drive in each subset failed, ...
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2answers
205 views

Recovering RAID5 array after zeroing wrong superblock

I have a raid5 array on 4 disks, sda1, sdb1, sdd1 and sde1. sdd1 was removed but is a healthy drive. While attempting to re-add it, I accidentally zeroed out the superblock for sdb1. sdb1's data is ...
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2answers
78 views

erased md0, md1 and can't recreate them

I previously had a working RAID 1 array. I think as a result of running grub-install /dev/sdb and grub-install /dev/sdc I somehow wiped my computer of md0 and md1. I need to set them up again. When ...
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1answer
124 views

mdadm raid6 array reports incorrect size in df -h after grow

I've recently grown a 5x 3tb mdadm raid6 array (8tb) with a sixth disc in fedora 18, and after full rebuild and check, "mdadm --detail /dev/md127" returns the below: Version : 1.2 Creation ...
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1answer
315 views

How to boot after RAID failure (software RAID)?

Previously I had a software raid set up using (mdadm) of drives sda and sdb. sdb failed and the only way to reboot the system was by unplugging the second hard drive. Now I've added fresh sdb and sdc ...
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4answers
205 views

Hardware Acceleration for MD RAID?

Is it possible, or feasible, or even sensible to consider hardware acceleration for MD RAID? I am referring more here to RAID6 type levels where there is a computation overhead. My thinking is that ...
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1answer
397 views

Creating raid1 array with mdadm cuts space

I'm trying to create RAID1 mirrored disks on already deployed system (CentOS 6.4). I have two disks: source /dev/sda with the OS and /dev/sdb which will be the mirror. The disks are connected from ...