A linux utility used to manage software RAID devices.

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create raid1 from existing lvm local volume

I have an existing LVM, with one physical drive (say /dev/sdb), and one volume group (say volgrp1), here I have three logical volumes (say lvSys, lvHome, lvSwap). Now I worry about my data and by a ...
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1answer
90 views

Dependency failed for mount after dist-upgrade

Last weekend, I ran an apt-get dist-upgrade on a home Debian 8.3 system, and was surprised to see that it entered emergency mode on the next boot. The server in question runs LVM on top of a mdadm ...
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0answers
23 views

MD RAID 5 module doesn't load at boot

I recently upgraded my NAS to kernel 4.4 and now my md raid 5 array doesn't assemble itself at boot. dmesg reveals this: [ 2.299666] md: personality for level 5 is not loaded! and doing lsmod | ...
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17 views

raid5 array reassembles as raid0

I found simmilar problem here: Missing mdadm raid5 array reassembles as raid0 after powerout, but mine is a bit different. Here too my raid5 reassembles as raid0, but i don't see any of my devices ...
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0answers
34 views

Ubuntu Server: How to make bootable bios_grub RAID device?

I have a stable Ubuntu (14.04.3) Server-powered file server that I have set up, and want to set up a RAID10 array for it. For reference, I have been following this guide so far, but using RAID10 ...
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0answers
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What chunks are mismatched in a Linux md array?

This is a repost of a question I asked on ServerFault and was automatically deleted for lack of activity. Let's hope it will have better luck here. After performing a "check" (by writing check to ...
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0answers
24 views

lsblk shows non-existent md partitions after reboot

I'm getting weird behaviour while setting up an mdadm RAID1 array on debian 8.2. After I set-up the array, lsblk shows: simon@debian-server:~$ lsblk NAME MAJ:MIN RM SIZE ...
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1answer
12 views

What happens if Host OS of MDADM md0 crashes

So I am debating getting software RAID. But I am trying to reduce the single point of failure problem. I don't think hardware raid is an option as I can't afford a high-end adapter, and I think I like ...
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13 views

mdadm raid 1 array superblock can't be ready

I have a ubuntu linux box, with a raid mirror, 2x3TB using mdadm It's not the system disk, but a raid 1 mirror that contains some files I really need to keep. After power cut, restarted and now ...
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1answer
24 views

Is there a way to rebuild only part of a disk in an mdraid5 setup?

Last night I accidentally used dd to overwrite the first ~20GB of a drive in a RAID5 array. When I noticed, I repaired the array with $ mdadm --fail /dev/md127 /dev/sdb $ mdadm --remove /dev/md127 ...
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33 views

RAID5 needs drive to be added every reboot

I have a 3 disk RAID5 mdadm array total 4TB on an Ubuntu Server 14.04.3 LTS. Since a kernel panic caused by an already replaced device unrelated to the array, after every reboot the array starts ...
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0answers
19 views

RAID1 superblock recovery

I have a big issue with my RAID1 array. I transferred my RAID1 (mdadm) to a new PC, but when I was installing it, I rebuilt the array as a RAID0. No data has been written to the disks. When I try ...
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1answer
24 views

What happens if my RAID fails while the swap is on it?

Today I removed swap from the system drive on my Debian. And created a swapfile on md0. So, I have a RAID1 array for data and a swapfile (the only swapfile). The system with boot partition is on ...
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2answers
40 views

I'd like to verify mdadm RAID1 is completely fine

Is there some mdadm --verify similar command, which would read all sectors of both disks in RAID1 to truly verify it's fine?
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0answers
12 views

How to make mdstat ignore specified devices

I have a hypervisor with KVM that uses zvols for virtual machine storage. One such virtual machine was moved from a physical one and has software RAID inside it. Zvols are detected as block devices on ...
4
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1answer
72 views

Why does mdadm believe my raid1 “has failed so using --add cannot work”?

TLDR: Trying to add a blank partition to a degraded RAID1 with mdadm 3.3.2 (Debian Jessie) fails, saying the (perfectly working!) array has "failed" and "--add cannot work". Is it telling me of a real ...
4
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1answer
127 views

Configuring a mdadm RAID-1 on SSD and HDD

I need to configure a RAID-1 on one SSD and one HDD. Both SSD and HDD has some preinstalled software, which I don't need so both can be fully wiped if that is any advantage. My research so far lead ...
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1answer
145 views

FIx RAID configuration after upgrade to Debian/Jessie with ICH9 chipset

I upgraded from Squeeze to Wheezy without problems. But after upgrading to Jessie the system cannot boot anymore (using LILO). LILO ERROR: Duplicated Volume ID O 24.1 Loading Linux ....(snip) BIOS ...
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2answers
141 views

MDADM RAID 0 Failure

Last night I noticed my system clock on my Ubuntu Server was 5 minutes fast so I ran an 'ntpdate pool.ntp.org' command and went to bed. This morning I noticed that SAMBA shares were not working. ...
2
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1answer
349 views

mdadm: /dev/md0 assembled from 3 drives - not enough to start the array

I had a drive in my raid5 fail a while back. I believe the problem was due to a power failure at the time, but originally thought it might be the hard drive controllers on the motherboard. (this is ...
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2answers
41 views

how to access data on RAID10 (consisting of 2 disks) using only 1 disk?

A long time ago I setup a RAID consisting of 2 disks. I wanted more than else safety/redundancy and indeed I think I wanted a RAID1. Now I have only access to one of those 2 disks and looking at it I ...
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40 views

raid10 “recovery aborted due to read error” drives being marked spare

I'm trying to recover my RAID10 array. All devices are plugged into a PCI controller that I've been using for a number of years now. I just replaced all of the drives in the system, as they all seemed ...
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1answer
59 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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1answer
154 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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3answers
33 views

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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1answer
79 views

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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0answers
79 views

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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1answer
210 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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1answer
150 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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2answers
1k 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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3answers
104 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 ...
2
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1answer
145 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 ...
2
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1answer
249 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 ...
2
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1answer
287 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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2answers
604 views

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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3answers
994 views

mdadm: can't remove components in RAID 1

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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1answer
1k 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 ...
3
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1answer
375 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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1answer
467 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 ...
2
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1answer
493 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 ...
3
votes
1answer
63 views

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 ...
2
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1answer
2k 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 ...
5
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1answer
346 views

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
133 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 ...
2
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2answers
59 views

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 ...
2
votes
1answer
69 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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3answers
935 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 ...
3
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1answer
316 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 ...
5
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1answer
4k 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 ...