A linux utility used to manage software RAID devices.

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“Spare” disk in a 2-disk mdadm RAID1 array?

I recently had a RAID1 volume fail. It had three primary partitions in it, all participating in separate, but similarly configured VGs. This configuration comes from the fact that the machine is ...
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10 views

mdadm RAID10 - change broken disk

Tonight my server stopped answering to ssh, ping, so I drove to the server room. Server did not respond to keyboard (even Ctrl-Alt-Del), there was no data on screen (it was black, no symbols on it), ...
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32 views

RAID mdadm virtual disk too small

sudo mdadm --build /dev/md0 --level=linear --raid-devices=3 /dev/loop0 /dev/sda1 /dev/sda2 After running the above command, /dev/md0 is smaller than /dev/loop0 + /dev/sda1 + /dev/sda2. Why is that ...
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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 ...
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Replacing a disk to RAID5 failed

I removed a faulty disk from my RAID5 with mdadm --manage /dev/md0 -r /dev/sdd1 and replaced it with a new one. I tried to add it with mdadm --manage /dev/md0 -a /dev/sdd1 but it's only added as a ...
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255 views

Shrinking LVM physical volume on top of mdadm degraded RAID array, adding a spare and rebuilding it

I have a Debian Wheezy system with a couple of 500 GB HDDs in RAID-1 (mdadm mirror), on top of which sits LVM logical volumes with 5 partitions (boot, root, usr, var and tmp), total size of 47.15 GiB. ...
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Is it sensible to use multiple LVM layers with mdraid

I'm building up a home server that will be used for a handful of different things. I'd really like to try a Btrfs raid 1 array for a large data store, but I'm using CentOS 7 (older kernel although ...
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Boot GRUB2 with Degraded RAID5

I am building a custom NAS with Debian Jessie. Has three 4TB hard drives in a software RAID5 configuration. Works perfectly when all three drives are present. I am trying to test what happens when if ...
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How to check mdadm raids while running?

I'm starting to get a collection of computers at home and to support them I have my "server" linux box running a raid array. Its currently mdadm raid1, going to raid5 once I have more drives (and ...
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36 views

mdadm raid filesystem differs from disk filesystem

I have created a raid 5 using mdadm on Debian. I used 2 new and 1 "old" disks. The old one had ext3 before. Using "parted -l" I noticed the raid has ext4 as filesystem but the old disk has ext3. I ...
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67 views

File transfer between SSD and RAID array uber-slow

It's really simple: this server has an SSD for the main drive, and a RAID array (mdadm) for storage. Intermittently, it has a problem writing to the array: the write speeds slow down to the point ...
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25 views

RAID boot drive not found after mdadm upgrade

I was having trouble getting a new RAID array to assemble on startup, and before anyone responded to that post, I tried updating mdadm, but this ended up taking a very long time because of all the ...
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60 views

New RAID array will not auto assemble, leads to boot problems

I had just asked this question where I was unable to boot after installing a new RAID1 Array. I was able to get to the terminal, but once I sorted that out I realized that my problem isn't so much an ...
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49 views

mdadm refuses to add second identical disk to array

I have a RAID 1 array which is in a degraded state and want to add another drive to it. # mdadm --detail /dev/md1 /dev/md1: Version : 1.2 Creation Time : Fri Mar 21 17:23:00 2014 Raid ...
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mdadm arrays referencing the same devices

I've a software RAID setup for one of my servers. Now there are two arrays that reference the same devices (md126/md127 - see below) where one of them is marked inactive. I want to understand what ...
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127 views

Resize MDADM/Software RAID underlying partition and filesystem

I am running out of space on my root partition and would like to steal some from a different partition. The drives are 2x120GB with mdadm software RAID. I am using CentOS 6.5 64-bit. I used the centos ...
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81 views

Data Recovery from a 4-Disk NAS RAID 10

I know there are similar questions to this but none specific to RAID 10 extracted from a NAS, so any help is greatly appreciated. So, basically the NAS is kaput but the drives are ok. Following the ...
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235 views

Missing mdadm raid5 array reassembles as raid0 after powerout

I had RAID5 array of three disks with no spares. There was a power out, and on reboot, the array failed to come back up. In fact, it the /dev/md127 device disappeared entirely, and was replaced by an ...
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131 views

How to assemble a specific RAID array without using /etc/mdadm.conf

Is it possible to assemble a specific RAID array using mdadm and its scan-functionality, but without the need for a configuration file? Background: I'm using a custom-made initramfs to setup my ...
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1answer
68 views

proper way to stop software RAID before system shutdown

This should be straightforward, but I have been unable to find a direct answer by searching. I find that if I unmount an mdadm-managed array and then either (1) unplug the array, (2) power off the ...
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85 views

Centos 7: /dev/md/root instead of /dev/md0

I have in mdadm.conf the following: ARRAY /dev/md/root level=raid1 num-devices=2 UUID=331de03d:8ba39777:3b664baf:36366f33 But here is mdadm.conf example with the following: ARRAY /dev/md0 ...
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Raid devices are mounted with different UUID

Centos 7.1 64. This is what I have: Two raids, but not md0 and md1 [root@localhost]# cat /proc/mdstat Personalities : [raid1] md126 : active raid1 sdb2[1] sda2[0] 974711616 blocks super 1.0 ...
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How to restore RAID5 Array

I have a RAID5 array consisting of 3 identical 2TB drives. Suddenly GRUB wouldn't boot anymore and gave the error out of disk. Eventually booted a livecd and ran some mdadm commands: mdadm --examine ...
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200 views

RAID6 scrubbing mismatch repair?

You can initiate a scrub of a mdadm array with echo 'check' > /sys/block/mdX/md/sync_action, and if a bad sector is found, it'll rewrite it automatically (from a mirror or from parity information ...
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mdadm - Can't Remove Components In RADI1

I have my /boot partition in a RAID 1 array using mdadm. This array has degraded a few times in the past, and every time I remove the physical drive, add a new one, bring the array being to normal, ...
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209 views

Required GRUB modules for booting on mdadm RAID1

I have a mdadm-managed RAID1 with a single EXT4 partition on it (having both the OS files and GRUB's files in /boot/grub), and I'd like to know what modules and what configuration do I need for GRUB ...
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185 views

Can BTRFS stripe RAID arrays?

I've been using an Ext3/4+lvm2+mdadm file system setup for about 5 years on a file server. This has grown (and moved processors a couple of times) and I've moved disks between systems ...
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703 views

mdadm RAID 5 and parted unrecognized disk label

I have three 3 TB drives that I am attempting to put together into a RAID 5 setup with mdadm, but I am running into some issues. (Actually, I have four 3 TB drives I will be using, but one of them ...
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3k views

bit rot detection and correction with mdadm

I'm about to re-organise all my HDDs in my linux box nas and would like to use mdadm raid for data protection and its flexibility for reshaping the arrays. However, before I use mdadm for this I'd ...
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/dev/md127 refuses to stop. No open files

So I'm trying to stop /dev/md127 on my Ubuntu 12.10 box. It was set up as RAID1, but I'm trying to move everything (well, rename) to md0. I read that renaming isn't possible, so I'm trying to remove ...
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134 views

Revert btrfs to ext4 on mdadm raid

I have a Raid 5 setup using devices rather than partitions. I recently converted the ext4 fs on the md device to btrfs. I was initially happy with btrfs, but to be short, it's eating up CPU cycles ...
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RAID resyncing automatically?

I rather randomly checked the status of my RAID arrays with cat/proc/mdstat and realized, that one of my arrays seems to be resyncing: md1 : active raid1 sdb7[1] sdc7[0] 238340224 blocks [2/2] ...
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1answer
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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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1answer
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How mdadm recognizes which device is right one to sync others with

Imagine you have mdadm raid1 with 2 disks. Then you turn off the server, split the disks each one to different machine and boot both of them, so they will become slightly inconsistent Now you turn ...
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1answer
96 views

mount mdadm disk without partition table

I've a debian installation and during the installation I had made 3 mdadm raid disk: swap, root and home. I had done it with partman and it had made the mdadm disk without partition table. Now I want ...
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challenging failed raid5 recovery

I have a personal raid 5 array that is in rough shape. The failed array has eight 2 TB drives that were built up over time in my n-2 desktop machine. The array is from an in-house computer that ...
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1answer
52 views

Rebuild linux raid array?

I'm going to be building a media server soon and I want to know how hard it would be to rebuild an array in the event of an ssd failure. Here's what I'm doing. I'm going to have a 128GB SSD boot drive ...
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339 views

How to map a sata device name to a physical sata interface for RAID systems

I have a system with 10 SATA ports, and another SATA as the boot disk. The 10 SATA ports make up 5 software RAID1 arrays. The RAID disks may be removed between boots, and swapped in with arbitrary ...
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mdadm raid doesn't mount

I have a raid array defined in /etc/mdadm.conf like this: ARRAY /dev/md0 devices=/dev/sdb6,/dev/sdc6 ARRAY /dev/md1 devices=/dev/sdb7,/dev/sdc7 but when I try to mount them, I get this: # mount ...
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Grub multi-disk/RAID configuration not booting

I have a system with 2 SSDs configured in BIOS as a Raid 0 volume. The system came with Windows 8 pre-installed. I would like to multi-boot Windows 8 and Debian 7. The Debian installation disk ...
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1answer
210 views

Unable to check a mdadm RAID1 array, says the file system's read only?

I recently migrated a RAID1 from a CentOS 5 system to a CentOS 6 system and ever since when I attempt to perform a check I get the following: $ echo 'check' > /sys/block/md127/md/sync_action ...
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1answer
2k views

Grub-install: embedding is not possible in Bios/GPT

I am struggling with setting up an encrypted NAS for some days now. The basic plan is to have btrfs on lvm on luks on raid1 with lvmcache in writeback mode thrown in for the root partition to reduce ...
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563 views

Reassemble mdadm-raid5

A friend of mine has a mdadm-raid5 with 9 disks which does not reassemble anymore. After having a look at the syslog I found that the disk sdi was kicked from the array: Jul 6 08:43:25 nasty ...
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An existing mdadm RAID5 is not mounting, Either a problem drive or Superblock

I have 4 x 3TB NAS setup as RAID5 which has been working great for almost a year. After a recent abrupt shutdown (had to hit the power button) the RAID will no longer mount on boot up. I've run: ...
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Backup and restore of raid1 device, after OS upgrade

We have a physical RedHat server with two 60GB local disks, and two RAID 1 devices on them. There are also a few multipathed SAN luns. Disk /dev/sda: 60.0 GB, 60022480896 bytes Device Boot ...
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Raid 5 not starting

I had a raid 5 with 3 disks in my old computer, but the motherboard died. I put all the disks in a New computer, but the raid doesn't want the start anymore. When booting the pc, i can see all ...
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1answer
634 views

RAID-1 doesn't Assemble, elements listed as SPARE, how to recover?

I recently moved my Kubuntu 12.04 workstation to a new location. It was shutdown normally but when I rebooted it in its new home the RAID-1 array /dev/md0 was GONE! The Elements of the array are ...
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114 views

Degraded RAID1 array boots with one drive, not with the other

UPDATE It seems initramfs fails to properly mount the array. If I stop and reassemble them, they works: mdadm --stop /dev/md124 mdadm --assemble --run /dev/md124 /dev/sda6 Maybe initrd tries to ...
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Mdadm not adding all disks to raid

A couple of years ago, I installed a raid 5 with mdadm on a fedora box. The old hardware died recently, and I have put the boot disk in a newer desktop pc, and added the thee raid disks via usb. So ...
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602 views

Using Grub2 to boot linux mdraid whole device RAID6

Linux mdraid supports device RAID (as opposed to partition RAID). The new superblock versions are also smart enough to not put the meta data right at the start of a disk. Does that mean it's possible ...