Questions tagged [mdadm]

A linux utility used to manage software RAID devices.

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CentOS: What steps are needed to move my entire server (OS/boot/storage) from one mdadm raid 1 array to a new one?

I have a pair of large nVME drives in my CentOS 8 Stream server, configured in mdadm raid 1. I wish to install a pair of smaller (cheaper) nVME drives, move everything across, and then remove the ...
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Weekly RAID check affecting my system - any way to mitigate?

I recently got my webhost (Hetzner) to add a paid of 16TB SATA drives to my webserver. Currently using 2.5TB of them. They're RAID 1 mirrored. I also have two 4TB nVME drives with 700GB currently on ...
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RAID5 compatability: zeroed superblock: WD Red 8TB drives: wd80efax-68LHPN0 and 2x 68KNBN0

Summarizing the problem: I have been scraping by with JBOD for years, but finally need a real 'micro data center'. I bought 3 drives for my centos8-stream box over a couple months, but I have heard it ...
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centos7.9 mdadm raid0's performance which is only 50% of centos8 mdadm raid0

I use the same PC and same NVMe SSDs do the raid performance test on different OS. The steps are as follows: mdadm -C -v /dev/md0 -l0 -n4 /dev/nvme[0123]n1 mkfs.xfs /dev/md0 mount -o discard /dev/md0 ...
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What does `mdadm --manage /dev/md1` do? Do I need to "undo" it?

I ran this hoping to find out a bit about my array (I now know I should have used --detail). But I'm not clear what the --manage option does. It gave no output, and just put me back to the bash ...
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DegradedArray Event Detected - U_ but only one drive listed

I got this email from the dedicated server hosting company: A DegradedArray event had been detected on md device /dev/md/0. The /proc/mdstat file currently contains the following: Personalities : [...
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mdstat mismatch cnt unsynchronized blocks

Both of our servers suffer from mdstat mismatch cnt unsynchronized blocks Every start of the month we got this error and we have to repair the raid using echo 'repair' >/sys/block/<md id>/md/...
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How to move a Linux software RAID setup from 1 server to another (Debian)

Currently, I have three USB drives running as a RAID-5 set on a Debian-9 server. All is well. I would like to safely move them to a different server, running Debian-10. The host name of the current ...
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Can you install GRUB on an MDADM Raid 1 device before it's added to the MD array?

So we have our 2 OS drives in a Raid 1 MDADM mirror. One of these drives has failed. Typically after replacing the failed drive, we do a sfdisk command to match the partition table, and then add the ...
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PCI NVMe mdadm RAID1 performance too slow

I know this has been discussed multiple times but I have not found any solution so far that worked so posting here hoping there is some solutions in Dec 2021… I have a Dell R640 server with dual Xeon ...
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Attempting to create an RAID array in Ubuntu server 20.10

I'm attempting to create a RAID 0 RAID array on Ubuntu server 21.10, but I keep getting the following error: mdadm: An option must be given to set the mode before a second device Here is the syntax I ...
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FAILED md RAID10, confusing output

I'm testing a RAID10 array here with mdadm. I wanted to see how many failed devices it could tolerate, rebuild times, etc. At one point I had it doing a resync on 5 or 6 devices, then I rebooted it, ...
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Does Linux md-raid store backup metadata anywhere on the disk?

I know that with ext2/3/4 and other filesystems, copies of the superblock are stored throughout the disk in case the primary superblock is corrupted (https://ext4.wiki.kernel.org/index.php/...
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How do I resize the filesystem on a RAID array?

I've recently added a 5th drive to my software raid array -- and mdadm has accepted it: $ lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT nvme0n1 259:0 0 894.3G 0 disk ├─...
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Openmediavault assemble raid6 with mdadm

I have a raid 6 with 1 hot spare. I the initial config was with 5 6TB drives then I added 2 more 6TB drives with the openmediavault web interface. Everything was fine after that. But the last time ...
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How to increase speed of RAID 5 with mdadm + luks + lvm

I think I am kinda lost with my current server setup. It is an HP Proliant dl160 gen 6, and I put 4 spinning disks with a setup that has mdmadm + luks + lvm and on top of it btrfs (maybe I went too ...
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Properly Boot a Software-Based RAID1 with a Missing or Improperly Failed Drive

tl;dr. Is there a way to properly boot a software-based RAID1 with a missing or failed drive (that wasn't failed by the user first)? To be clear, booting a software-based RAID1 without a hard drive ...
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RAID1 Recovery after Degradation

Below is the output from lsblk, mdadm and /proc/mdstat for my 2 disk Raid1 array anand@ironman:~$ lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 ...
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Is it safe to use dmcrypt on top of software raid?

I'm designing a machine, to serve as a NAS. My interest is hobby-level. I would use mdadm to software raid a couple of same-size hdds. At first I'd use raid1, but in the future I'd add another disk ...
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mdadm RAID: Stuck at 0% Grow (Shrink) reshape due to bad geometry

I have a linux software Raid5 array (md1), containing 4 x 16TB + 2 x 8TB hard drives. 2 x 8TB hard drives were merged together (Raid0 array; md0), working as a (fifth) 16TB device. This is just for ...
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Have to manually build RAID array every boot and cannot add third drive - MDADM

I have a RAID1 array that I've had to manually rebuild every time the system boots for a long time. Never had time to figure out why. This is the command I've been using to rebuild it every boot: sudo ...
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Replaced all mdadm RAID1 drives with new, larger drives. Now can not boot from the RAID1

I have simply replaced all of my mdadm array hard drives with some larger drives. I then went to reboot the system and upon booting it comes up with a grub error. I'm not sure what is needed to be ...
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How to create LVM RAID 1 with 4 disks of 2 different sizes?

I have a system with 2 x 1TB (NVMe SSDs) 2 x 2TB (SATA SSDs) disks and would like to create a RAID 1 system using all available disks (so I have a 3TB RAID1 system at the end). Unfortunately, most ...
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Rebuild RAID5 with uncorrectable sectors on multiple disks

My software RAID5 (mdadm) system consists of five disks. Recently, I get I/O errors when reading certain files. Most of the other files are still readable. At first, I was planning to find out which ...
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Separating /boot from the rest of the System

I have a theoretical system configuration question; If I build my system on a software RAID1 but put /boot on a USB.. could there be problems if the RAID becomes dirty? The setup would be as follows: ...
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How can I migrate soft RAID array made by mdadm to new server and new OS?

I have a RAID array which level is raid0 and made by mdadm, in my old server. The member of this array is 6 NVMe SSD, and I create this array with below command: sudo mdadm -C /dev/md0 -l 0 -n 6 /dev/...
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Why is mdadm unable to deal with an "almost failed" disk?

Multiple times in my career now I've come across mdadm RAID sets (RAID1+0, 5, 6 etc) in various environments (e.g. CentOS/Debian boxes, Synology/QNAP NASes) which appear to be simply unable to handle ...
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RAID10 software raid converted as RAID0

On one of the server, The RAID10 software raid volume had became RAID0 after one the disks in the RAID10 disk group failed. Also the converted RAID0 volume has become inactive. How can we recover the ...
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RAID 10 not showing full capacity

I am currently in the process of trying to setup a software raid using mdadm on my linux machine. My system has 4x 8TB (all are exact same model) which I would like to put into a RAID 10. However, ...
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mdadm - cant read superblock - can I zero the superblocks without erasing data and recreate a raid?

Today I had to fix a Server Fan by disassembling and rebuild it. After booting the server I had the problem that all disks where not at the same location they have been yesterday. So the system ...
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Linux mdraid resync speed on 36 drive array

I have some performance issue with mdraid. I have one 18x10TB soft raid6 array that is resyncing at ~70MB/s: kernel 5.8.13-1.el8 /dev/md0: Version : 1.2 Creation Time : Mon Oct 5 15:...
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How to delete an inactive RAID array - Centos 6

I have recently resized a logical volume group and a logical volume to fit into a RAID-0 configuration on Centos 6.10 system. Everything seems to be working fine. However, the disk utility shows two ...
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mdadm partitions gone after reboot

I had a RAID 6 setup in Cockpit UI with multiple partitions. There was one partition in particular that I wanted to extend from 10TB to 11TB using available space and attempted on /dev/md127p6 using &...
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Recover Linux RAID1 - FAT32 but shows ext2, can't assemble, but shows backup superblocks...I am STUCK

I have 2 physical disks in linux RAID1, I am not sure what happened, I think someone who should not have been in the system partitioned the md0 by mistake while the system was running while trying to ...
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Mount a HDD from a RAID to recover some data

I'm struggling to mount a HDD from a Synology DS214 RAID1 on my computer to backup some data from it. I can't mount directly because this HDD come from a raid mount /dev/sda1 /mnt mount: unknown ...
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Rebuilding an inactive RAID5

I have a 7 x 14TB RAID5 in my workstation with Centos 7. Last week one of the drives was marked as faulty by SMART (/dev/sde). I used mdadm to mark this drive as faulty and to remove it from the array ...
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How to use mdadm to assemble arrays from crashed windows server

I got 12 hard disks from completely crashed server, some of them are failing, too. I successfully saved bit copy of all of them, even not always error free. I found 512MB superblock on each end of ...
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different mdadm RAID on same disk?

I am looking for factual knowledge or actual measurements to validate or not my idea. Please, hold answers without data just saying it is a weird idea because not the most common setup. short question:...
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mdadm how to use an array as a "member disk" in another array

I HAD a 4-disk RAID 5 array with MDADM. One of the disks failed. I bought a new disk three times the size of original disks as replacement. I now have 3x5TB disks in a degraded RAID5 1x16TB disk free ...
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MDADM Raid 5 stuck on "Check Status 98% Complete"

I have an ubuntu server running that works like a NVR and stores recordings from a IP Camera over the network. It worked fine for a little over a month, then today when I went to check on it, it hadn'...
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Raid-10 mdadm - How to Manually Configure Mirrored Drive Order?

How do I configure a new mdadm software RAID-10 to use a specific order for its drive mirroring? Say I have 4 hard drives: A, B, C, and D. For my own reliability and performance reasons, I want drive ...
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Does Software RAID-1 Double The Writes Over The Controller/Interface?

Say I have two hard drives that max at 200 MBytes/sec writes per hard drive. Now let's say both drives are in a USB enclosure that maxes at 300 MBytes/sec writes for the entire enclosure. When ...
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mdadm : assemble raid5 created with missing disk

2 years ago i've created a raid5 array with 2 disks like this : mdadm --create /dev/md0 --level=5 --raid-devices=3 /dev/sdb1 /dev/sdc1 missing Now i've rebuilt my system with latest ubuntu server LTS,...
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mdadm RAID5 RAID6 how to check consistency on running array

On mdadm softraid 6 (about 12 disks, 60TB) there appeared accidental misswrites in large files (>100GB). All system was checked - RAM, NIC, LSI RAID card. The most suspected is the LSI because its ...
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Better way to share HDD between KVM guests

Is there a better way to share HDD between multiply KVM guests at the same time then NFS? I have MDADM RAID 1 with all of my info and also I'm planning to take my Nextcloud to a KVM guest and want ...
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Recover mdadm array

I had a raid5 array built with mdadm and btrfs filesystem on top of it. My sata card failed and all my drives dropped at the same time. What should I do if I wanted to rebuild the array or restore ...
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High avgqu-sz & utilisation on madadm RAID 0 in AWS EC2 I3.8x large instance

I have an AWS EC2 i3.8xlarge with 4x1.9TB ephemeral storage volumes tied in mdadm RAID-0 (Yes, RAID 0) with XFS file system mounted using noatime and inode64 options. I am running an IO intensive ...
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Are my drives being utilized equally with Linux Software RAID 0 array?

I have four NVMe drives in a RAID 0 configuration. I am attempting to determine how many IOPS the array is handling. When I run iostat, it appears that one drive is handling more IO than the other ...
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RAID1 array always degraded when rebooted after changing SATA controller

My software RAID1 arrays (/boot, /) always become degraded when restarted after adding SATA controller. It's CentOS 7. Here is what happening and what had been done: I made 4-disks RAID1 arrays with ...
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Ways to make a backup on RAID5 filesystem (mdadm) with many files

I have a NAS containing RAID5 array (5.4TB in total, 2.9TB in use) using mdadm. Now I plan to modify some hardware of it (especially SATA controller), so I'd like to have a whole backup of this RAID5 ...
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