Questions tagged [mdadm]

A linux utility used to manage software RAID devices.

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Linux MD RAID with btrfs stuck and consume 100 % CPU

The issue During last several weeks, I am experiencing annoying issue on my physical server with Linux software RAID 6 (md, mdadm) with btrfs file system on it. Once in several days (irregularly, as ...
Vojta Myslivec's user avatar
2 votes
1 answer
211 views

Raid software (mdadm) has unexpected size

I have a server with 4 hard drives at 4 To (3.7 TiB). I first created a partition on each drive with type "fd" (Linux Raid Autodetect). Then, I configured a RAID 10 using mdadm with the following ...
Cyril N.'s user avatar
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Is my mdadm RAID1 running?

Sorry for the stupid question but I'm really confused. Is my RAID1 running and in a good health? lsb_release -a No LSB modules are available. Distributor ID: Debian Description: Debian GNU/Linux ...
Trayan Momkov's user avatar
34 votes
7 answers
13k views

How beneficial are self-healing filesystems for general usage?

I have recently looked into advanced filesystems (Btrfs, ZFS) for data redundancy and availability and got interested in the additional functionality they provide, especially their "self-healing" ...
Prototype700's user avatar
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Recovering mdadm 4-disk RAID5 array with 2 out of date disks

Edit: The scenario in this wiki, where 1 drive has a slightly lower and another a significantly lower event count than the rest of the array, suggests assembling with --force while leaving out the ...
guyyst's user avatar
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mdadm raid1 with three disks where two disks would be a subset raid [closed]

I currently have two disk of the same size (4TB each) in raid1. I'm wondering if it's now possible to add an additional disk of size 8TB and have it as raid 1 with the other two disks acting as raid ...
Chris Stryczynski's user avatar
2 votes
2 answers
406 views

Rebuild a temporary disconnected RAID device

If I build a RAID 5 array (specifically MD RAID on Linux) and then 1 of the drives disconnects for whatever reason, does that drive need to be rebuilt from scratch if: No data has been written to the ...
Livy's user avatar
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mdadm raid5: All disk appear as spare

I had a power plug removed for 2 of the 4 disks of my raid 5. Since then it cannot start. Even with --run --force, --readwrite, etc. I quickly saw it so the data should not be (too much) corrupted. ...
MappaM's user avatar
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Have I lost data? Can I copy a MD superblock from one drive to another?

My friend's RAID5 has lost two disks -- one failed months ago, apparently, but the other dropped out and the data is believed to be okay. I can run mdadm --examine on (clones of) the two surviving ...
Steve Almond's user avatar
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How to resolve a DegradedArray event when one drive has been permanently removed from RAID array?

When I installed my VPS some months ago (Ubuntu 18.04), the default RAID configuration was relying on 3 disks. I removed /dev/sdc from the array to create a new partition. RAID array is now as below: ...
Ken Addams's user avatar
4 votes
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MDADM Raid10 event mismatch after restart

I made a raid10 with 8x8TB drives the file system on it is XFS. I never had any issue with it. The raid is configured as near2 and internal bitmap. The drives are connected to a LSI-9211-8i in HBA ...
Jacob Dorais's user avatar
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873 views

nullmailer - Diagnostic-Code: SMTP; 550 5.1.0 <root@external_email_server.com> sender rejected (497)

What did I miss-configure to be getting MAILER-DAEMON errors? (I was trying to keep this post short, but it got a bit out of hand.) I am setting up an email alert system for when my RAID1 should go ...
MeSo2's user avatar
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1 answer
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mdadm raid5 starts recovery right after creation

just for getting some experience with mdadm I've put some HDD together and try a bit. I have 2 250 GB and one 500 GB HDD. I know thats not optimal for RAID5 and I'll only get 500 GB capacity in total. ...
Hannes's user avatar
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How to Install CentOS8 on LVM on Software RAID

I'm trying to do something that should in my mind be simple - I've done this plenty of times on other distros, but can't make any headway. I'm trying to Install CentOS8 on an LVM partition on ...
davidgo's user avatar
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unable to clear superblock on drive

I have a USB thumb drive that I briefly used in a raid 1 array. I don't need it in that array anymore (but need to add it to a different array) and hence would like to get rid of the old superblock ...
stdcerr's user avatar
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Is it possible to use software RAID inside a Docker container?

Before anyone asks why you'd want to do that, I'm using molecule to test my "infrastructure as code" locally before deploying it to actual machines. Start by creating two block devices: # dd if=/dev/...
Mike Conigliaro's user avatar
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1 answer
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Grow an mdadm RAID5 array with fewer, larger disks

I have a linux software RAID 5 array, made up of 5 x 3 TB drives, giving me roughly 12 TB in total. I want to replace the disks with newer 8 TB drives, but since these are still quite expensive, I ...
Jure Merhar's user avatar
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53 views

Working Nginx-PHP-FPM setup; then switched from RAID1 to RAID10, and now setup doesn't work

Converted a RAID 1 volume to RAID10. The file system appears to be exactly the same on the new RAID 10 volume as the previous RAID 1 volume. For some reason PHP-FPM won't take a symbolic link to ...
Dark Phoenix's user avatar
1 vote
1 answer
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Using raid-1 madm to shrink an existing 8TB EBS disk live. Possible ? Risks?

Initial situation I have a 8 TB EBS drive on Amazon (ext4, directly mounted without partitions) I didn't use sw-raid for ages, so my assumption might be wrong that I can shrink the disk that way. ...
John's user avatar
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Single software RAID partition missing after replacing failing HDD

I have a raid-1 with 5 partitions (md0 - md4). Last night one of the HDDs failed (the faulty RAID partition was md4), I removed it, replaced it with a new one and now in the rescue system suddenly ...
Tek's user avatar
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2 answers
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Software linux raid using physical passthrough disks

I'm using Vmware ESXI and I followed this guide to pass through 2 physical disks for a raid 1 array. If I set up an mdadm software raid using these two physical passthrough disks will something go ...
Moptop's user avatar
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Debian10 , RAID : did it changed since Debian9?

I'm installing a backup server with a Debian10 installed and running on its NVMe disks. It also has 4x6TB SATA hard drives, and I'm trying to set these up as a RAID0 array. I'm usually following the ...
BxlSofty's user avatar
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mdadm: failed to set writable for /dev/md126: Device or resource busy

yesterday my one of SSDs on my server came into a faulty state. Well at least mdadm --detail /dev/md126 said that. Also mdstat showed [2/1] [_U] on one of raid partitions (md126 specifically). I ...
N. G.'s user avatar
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mdadm doesnt't work in secure mode

Im trying to mount /dev/sda1 in secure mode (cause of troubles with boot loader), but i cant do it without mdamd. root@rescue / # mdadm mdadm will not execute and completion _mdadm exists. So, how ...
user1964654's user avatar
1 vote
0 answers
157 views

How to configure RAID-5 for OS root (Ubuntu Server 18.04)

I have a fresh dedicated server I have provisioned running Ubuntu Server 18.04 and with 3x480GB SSDs (no hardware RAID controller though). The UI of the hosting provider will not allow the “/boot” or “...
nickz's user avatar
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874 views

Can I make a mdadm raid on a file, not a block device?

I would like to play with mdadm, the Linux RAID system. I want to see what happens when you fail a drive, when you grow the raid etc etc. My initial thought was to create 4 equally sized files (...
Amandasaurus's user avatar
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How create RAID 1 on working Slackware 14.2?

I use Slackware 14.2 (with kernel 4.4.14-smp) on sda and I'm trying to create the RAID 1 with additional sdb. I'm using the VM VirtualBox. First, I have cleaned the sdb: dd if=/dev/zero of=/dev/sdb ...
infernalcucumber's user avatar
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usb jbod enclosure, software raid1; after reboot, mdraid using wrong devices

I mirrored two disks in a USB enclosure on my Arch box, created a filesystem, mounted it, copied a bunch of data over. Everything was great. Then I waited until the md sync was done and rebooted... #...
John Cholewa's user avatar
1 vote
0 answers
174 views

Recover a linux raid array after running "mdadm --create"?

So I did something stupid and I'm wondering if I have any options. I lost my OS drive (centos 7) but was able to keep my 4x 3tb raid drives. So I reinstalled centos on another drive and tried to ...
Bryan's user avatar
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1 vote
0 answers
176 views

Replaced raid controller, raid config missing, server not booting

My raid controller went bust, and my hoster OVH replaced it. They only offer hardware support, so after replacing the controller they left the machine in Rescue mode. When I put it in normal HD boot ...
Mr.Boon's user avatar
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733 views

Broken RAID Array, no superblock detected

I run a CentOS system with 2x SSD in RAID1 and 4X SAS drives in RAID10. Linux is installed on the RAID1 array. This morning I noticed that my RAID10 array (md4) had gone missing, and that my RAID1 ...
Mr.Boon's user avatar
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4 votes
1 answer
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RAID10 array check slow, and slowing

I run a new CentOS 7 machine. Linux runs on 2x SSD setup, and I also have 4x SAS drives setup in software RAID10. The RAID10 array is large, 4x 12TB drives, so 24TB usable. File system is: ext4 Now ...
Mr.Boon's user avatar
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1 vote
2 answers
242 views

Degraded soft raid1 not booting and showing raid0

I created a server setup with uefi boot and encrypted lvm partitions as you may can see here: root@debian:~# lsblk -o name,uuid,type,size NAME UUID ...
user543229's user avatar
3 votes
1 answer
211 views

mdadm raid5 was added as a spare to itself

I have a raid 5 device created with mdadm. I was working on it and long story short, I wanted to type mdadm --manage /dev/md127 -a /dev/sdd, but I accidentally typed mdadm --manage /dev/md127 -a /dev/...
qspitzer's user avatar
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4 votes
1 answer
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While RAID1 is resyncing after create, can i write files to it immediately?

I searched but i just found this. How to interrupt software raid resync? My question is can i write files to my raid1 device while... [root@centos ~]# cat /proc/mdstat Personalities : [raid1] ...
ShenLin's user avatar
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1 answer
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Access clean RAID5 on new machine using 2 of 3 disks

A server of mine is dead. On the server I had 3x disk with a software raid on the second partition of every HD. Now I have inserted two out of three HDs in a PC (no place for the third!). Here what I'...
PeptideChain's user avatar
0 votes
0 answers
925 views

How do I mount a linux_raid_member filesystem with my Ubuntu machine?

We have a server that just died after ten years of service. It has four hard drives. Two are in one Raid 1 array and two are in another. I have managed to merge the firs two back into being one ...
Nicholas Tucker's user avatar
0 votes
1 answer
367 views

Is it possible to reboot server from /dev/sdb while RAID 1 rebuilds /dev/sda?

I have a dedicated server with a Raid I with /dev/sda and /dev/sdb in which /dev/sda started to fail so I ordered its replacement. After the intervention the server went into rescue mode and I was not ...
Javi Prieto's user avatar
3 votes
2 answers
4k views

Kickstart CentOS 7 with software RAID 1, but no LVM needed

I am going to Kickstart a CentOS 7.x installation with software RAID 1 remotely for the first time. So I am kinda inexperienced at this and wondering what I need to make this work correctly. A CentOS ...
HudsonHawk's user avatar
1 vote
0 answers
1k views

Mdadm Create array on partitioned disks - failed to write metadata to disk

I'm trying to setup a raid array for a server. The array is going to be RAID 5, consisting of 4 disks, sdc, sdd, sde, sdf I need three partitions of specific sizes (2gb 200gb 700gb) and they need to ...
Sgt_Breakneck's user avatar
1 vote
0 answers
205 views

Dismounting MD RAID1 LUKS-encrypted volume with partitions

Fedora 29. I created a 5TB RAID1 volume using mdadm. I then encrypted the volume with cryptsetup luksFormat. I then created ext4 partitions on the encrypted volume. (I did it this way so I can add ...
RoUS's user avatar
  • 141
6 votes
1 answer
388 views

Storage Setup for iSCSI/NFS servers

We are preparing to replace our storage servers (iSCSI+NFS). The current servers are Debian Wheezy using mdadm+lvm2 for storage, and failover using drbd and heartbeat (never got heartbeat to work). ...
Rod's user avatar
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1 vote
0 answers
55 views

How can I find a broken disc?

I have a problem. I got 1 broken disc in RAID6. How can I find which one broke down? I've tried # cat /proc/mdstat <--- to check condition of raid. I want to know if this command mdadm –...
kernels's user avatar
  • 11
-2 votes
1 answer
731 views

Hybrid RAID (SDD+HDD) gives unexpected results [closed]

I am doing some experiments with hybrid RAID in Linux. My test consists of the following: 2x256GB SSD in RAID 0 (/dev/md1) 2x256GB HDD in RAID 0 (/dev/md2) Then I made md1 and md2 into a RAID 1 (/...
Daniele Testa's user avatar
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0 answers
1k views

Reload of mdadm.conf live server

Is there a way how to make system to use updated mdadm.conf without reboot? I added spare group, but its not used yet - when there is a disk missing, spare is not automatically attached. I was told ...
J B's user avatar
  • 93
0 votes
1 answer
652 views

mdadm does not show every device as active

Recently, I had to resize a linux software RAID array. It has been a little bit complex as I was forced to do many steps to grow the device size while shrinking the number of members from 14 to 6. It ...
user3693367's user avatar
0 votes
1 answer
112 views

Unwanted md arrays created while creating SW RAID6 pool

I ran into issue where while i am creating bunch of RAID6 arrays on storage server, some unwanted random arrays were created with them for no reason. I am using old disks but i ran mdadm --zero-...
J B's user avatar
  • 93
6 votes
1 answer
2k views

How to recover mdadm raid6 array? mount: can't read superblock. 8/13 drives show all drives present, 5/13 drives show only 5 drives present

I rebooted my server today to find it hanging. I commented out the entry in fstab that loads /dev/md0 and the machine proceeded to boot. The raid was accessible and working prior to the reboot, I only ...
Jieiku's user avatar
  • 181
1 vote
0 answers
369 views

mdadm array does not assemble correctly

After a hard reboot, my raid10 array (made of 4 disk partitions) failed to reassemble. After many trials, i attempted the "nuclear" option of zeroing the superblocks and re-creating the array with the ...
orionbelt's user avatar
1 vote
1 answer
226 views

Ubuntu Not Starting Second RAID Array

Before I start let me say that I am by no means an expert with this stuff, if you see something that you would have done differently let me know. Ok, so I have a Ubuntu 18.04 server with a boot drive ...
Jacob Larsen's user avatar

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