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Questions tagged [md]

Multiple Device driver aka Linux Software RAID

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Raid 5 replace with read errors

I have a software RAID 5 with 3 disks. For a few days, sda has been giving errors, and today the new disk arrived. I launched mdadm --replace and the process started correctly, but due to read errors ...
Gabriel Rolland's user avatar
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Imported Linux raid (raid 5) assembled ok but cannot access data

This setup is a little convoluted. I have images of three 8TB drives from another Linux system that contain an md raid-5 setup. I have mounted these images as physical drives in windows (...
Walter ZAMBOTTI's user avatar
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md0 mount comes read-only after some writing

So I got a RAID 6 array (monitored) and I mount it to my filesystem (/mnt/mounting_point for this example). After some writing, for example: sudo fio --name=seqwrite --filename=/test/seqwrite.0.0 --rw=...
user2143364's user avatar
2 votes
3 answers
396 views

mdadm --zero-superblock for all devices of a mdraid?

I found no way to remove a mdraid from a server with one command. I can stop it via mdadm --stop /dev/md0 But the superblock is still in the devices. mdadm --zero-superblock DEVICE needs every device (...
guettli's user avatar
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Cancel `md --grow` operation

I added drives to an md RAID5 array, and quickly realized that I forgot to create a partition as is best practice (something I’ve also learned from bitter experience). How can I cancel this operation ...
Aleksandr Dubinsky's user avatar
-1 votes
1 answer
330 views

How do I resize the filesystem on a RAID0 array?

My server consists of 2x512GB and 1x3.5TB disks. root@bb2 ~ # lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT nvme0n1 259:0 0 476.9G 0 disk ├─nvme0n1p1 259:3 0 10.7G 0 part │ └─...
Mike S's user avatar
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Disk pair not usable after moving from hardware RAID (Windows) to software RAID (Linux)

A long time ago I created a RAID1 pair from the boot menu of a JMicron JMB363 card. All was working fine under Windows and the RAID1 array was recognized as a single disk. I don't remember exactly how ...
Bemipefe's user avatar
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14 votes
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When adding a new disk to RAID 1, why does it sync unused space?

I recently set up RAID 1 on Linux with mdadm. When adding a new HDD to RAID 1, data started to sync between my drives which is expected. I didn't expect that it started syncing the entire drive, ...
idunnololz's user avatar
0 votes
1 answer
207 views

Why do md array rebuilds start?

I've recently made mdadm report about the events and yesterday I received a number of rebuild events. Why was the rebuild started? I don't see anything relevant in the journal. Also I'm concerned ...
x-yuri's user avatar
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RAID is healthy but one device is unpartitioned - should I replace it?

I have a RAID5 array with 3 devices as follows: ~$ cat /proc/mdstat Personalities : [raid1] [linear] [multipath] [raid0] [raid6] [raid5] [raid4] [raid10] md127 : active raid5 sdb[4] sdc1[2] sda1[3] ...
TommyPeanuts's user avatar
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sudo mdadm --assemble --run /dev/md0 /dev/sdc1 mdadm: /dev/sdc1 is busy - skipping

I am able to mount /dev/md0 device but not sdc1. While mounting sdc1 getting below error. sudo mount /dev/sdc1 /mnt/s1/ mount: /mnt/s1: unknown filesystem type 'linux_raid_member'. janardha@saankhya-...
Janardha Veeramreddy's user avatar
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recovering lost access to RAID5

I had perfectly working RAID5 and added another device. I lost power during the RAID recovery. Now I have no access to it - it does not exist - lsblk does no longer recognize it as RAID5 - just ...
Jan Hus's user avatar
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4 votes
1 answer
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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/...
Paul Brannan's user avatar
2 votes
2 answers
3k views

Recover BTRFS? bad magic on superblock on /dev/md2

so after a recent power outage my DS718+ RAID crashed. After investigation with Syno Support we also identified that my RAM was broken (already removed) and as it was not a officially supported RAM ...
UnrealSlimShady's user avatar
2 votes
1 answer
175 views

How does Linux MD software RAID avoid assembling old and new devices into the same array?

On a Linux MD software RAID1 I removed a failed drive and added a new one. (All fine now.) The old drive and the new were never in the system at the same time. Do I see that right, that adding the old ...
Robert Siemer's user avatar
4 votes
1 answer
607 views

mdadm: power failure during raid1 rebuild

RAID1 array created with mdadm; array was rebuilding when there was a power failure. On coming back up, the array seems to be dead. # cat /proc/mdstat Personalities : [raid1] md0 : inactive sdb1[2](S) ...
user5416's user avatar
1 vote
0 answers
48 views

CentOS7 GPU cluster, expanding partition volume

I have a question. I'm trying to increase the disk partition to more than 50G, which I recall was the default given by CentOS7 during installation. I'm wondering how to go about doing so, since I have ...
Ming Lee's user avatar
2 votes
2 answers
964 views

2 disk raid0, move all data to one disk, so the other can be removed

I have a raid0 md disk made up of 2 equalized disks. I would like to remove & replace one of the disks (with a disk of the same capacity), without losing any data. Since the md filesystem is only ...
Amandasaurus's user avatar
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4 votes
1 answer
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How do I make grub install on a software-raid disk?

I am running Debian 9 with mdadm RAID 1 on it. Previously both hard-drives could boot into the OS, now only one of them can. I have recently had a faulty disk which needed to be replaced, so replace ...
Oleg's user avatar
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2 votes
0 answers
213 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
  • 151
4 votes
1 answer
6k views

mdadm: Resume initial sync

I have a new md RAID10 that I created (on a Synology DS416slim, which is besides the point), which was in the process of initial sync: root@ds416slim:~# cat /proc/mdstat Personalities : [linear] [...
Samveen's user avatar
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6 votes
2 answers
3k views

MD RAID - disable NCQ

Why is it recommended in a MD RAID (mdadm) to disable NCQ per-disk? echo 1 > /sys/block/sdX/device/queue_depth I read this tip in many articles regarding RAID tuning but nobody explains why.
Javier Franck's user avatar
3 votes
1 answer
336 views

(Why) Does lvmraid6 need 5 drives?

I'm investigating using LVMRAID instead of MD+LVM. In my case, I'm looking at a RAID6. As expected, the docs say you need N+1 devices for RAID5, and a minimum of 3 drives. The docs say for RAID 6 ...
tudor -Reinstate Monica-'s user avatar
1 vote
1 answer
415 views

How to pre-emptively repair/replace drive in linux md array without going degraded first?

I have (had, it's already been swapped out, asking this for future use) a drive that is indicating pending failure with internal SMART tests and bad block remaps. It is straightforward to mdadm --...
Nathan Neulinger's user avatar
1 vote
1 answer
116 views

Teaming a drive in multiple RAID groups [closed]

I've setup a home RAID for a friend in the past from a heap of old and new 2T and 3T drives. seems very much like what BeyondRAID does. I made a 7 member RAID5 group of the 2T volumes and the first ...
Ira's user avatar
  • 139
3 votes
1 answer
1k views

Data scrubbing and repairing a RAID1 mirror?

In Linux, if I have a software RAID1 mirror /dev/md1 with N ≥ 1 active devices, what are the semantics of the repair command? echo "repair" >/sys/block/md1/md/sync_action Am I correct to ...
jotik's user avatar
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1 vote
2 answers
3k views

md raid fails to boot with missing drive

I got a server with Debian Jessie, 4 Drives sda to sdd all of which are partitioned likewise. The system is in a raid1 md raid over all drives. All drives do have grub and I can swap discs with each ...
bardiir's user avatar
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21 votes
3 answers
39k views

How to re-add a drive when RAID is in degraded mode?

I am running an unmanaged Ubuntu server and due to recent performance issue and sent a request to the provider only to receive the following response: "Dear Client, as requested we have checked ...
captain lizard's user avatar
2 votes
1 answer
1k views

GPT, grub and mdadm. sda drive replaced, raid rebuilt in recovery mode, but now server won't boot

This is how partition table loooks like: (parted) print Model: ATA TOSHIBA DT01ACA2 (scsi) Disk /dev/sda: 2000GB Sector size (logical/...
Mladen Adamovic's user avatar
1 vote
1 answer
590 views

How to keep md-raid from blocking IO?

I run a server with md-raid (software) level 1 (2 HDDs mirroring) and several different applications run on it. The problem arises when file-intensive jobs (e.g. extracting large archives) run while ...
Cobra_Fast's user avatar
-1 votes
2 answers
1k views

Degraded md RAID5 won't boot

I'm running a Ubuntu server on a md RAID5. I started to have some issue with one disk, I received the following email from mdadm: A DegradedArray event had been detected on md device /dev/md/0. md0 : ...
Xantra's user avatar
  • 55
0 votes
1 answer
877 views

raid0 (soft-RAID using Linux md drivers) hosting XFS: how to repair after replacing bad disk?

So the latest configuration of our Nova compute nodes are using raw /dev/sdX devices (no labels nor partitions) as components for an md0 (raid0) array on which they're hosting an XFS filesystem. When ...
Jim Dennis's user avatar
2 votes
1 answer
1k views

SSD fstrim on CentOS 6.x with software raid5

I have some CentOS 6.x servers. They have software raid1 and fstrim works well there. On one of the servers, I decided to do software raid5 and ext4. I can mount it with discard and there is no error ...
Nick's user avatar
  • 882
2 votes
1 answer
934 views

dracut-pre-trigger rd.md=0 removing md raid activation boot fails

The system is Fedora 22, recently upgraded from Fedora 21. The remaining kernel from Fedora 21 boots. The two kernels installed after the upgrade fail to boot. The system is an Intel S-5000 PAL with 5 ...
dan sawyer's user avatar
0 votes
2 answers
94 views

Can I convert a single-disk system to software RAID1 without double-copying?

I have read this question: Can I create a "soft" RAID1 array without nuking data? as well as many other tutorials that layout this general process: Create degraded RAID1 array on new drive ...
Shelvacu's user avatar
  • 426
0 votes
2 answers
464 views

md raid10: how to make sure that replicated data is stored in right place?

When creating classic mirrored raids, it's usual to locate copies of data on disks of different kinds. In this case you would use a mix of disks of different series and manufacturers. That reduces the ...
michi.0x5d's user avatar
4 votes
1 answer
924 views

Debian server has degraded mdadm array on every boot

I have a Debian server with MD raid (2 actives, one spare): Personalities : [raid1] md1 : active raid1 sdc2[0] sdb2[1] sda2[2](S) 1068224 blocks [2/2] [UU] md0 : active raid1 sdc1[2](S) sdb1[...
Halfgaar's user avatar
  • 8,234
3 votes
1 answer
519 views

recover highly degraded raid array

I have a Linux RAID6 array (mdadm) composed of 8 disks. 2 disks failed. I replaced them, now I have 2 new empty disks. I would like to rebuild the raid but when I start a raid rebuild, the rebuild ...
exeral's user avatar
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MD RAID Array Often Starts Without All Drives

I find that, when I start/restart my system, my MD array often doesn't start with all of the drives even though the device-names haven't changed at all. I'll have to stop the array and reassemble it, ...
Dustin Oprea's user avatar
0 votes
3 answers
1k views

In a software RAID1, why does tune2fs -c 0 /dev/sda1 not throw an error but change is not seen in tune2fs -l /dev/sda1?

The Title pretty much says it all. Turn off mount count fsck seems to succeed: tune2fs -c 0 /dev/sda1 tune2fs -c 1 /dev/md0 But listing out via tune2fs -l /dev/sda1 shows mount count is set back to 1 ...
rjt's user avatar
  • 594
-1 votes
1 answer
2k views

Can RAID 6 support 3 or more parities? [closed]

It doesn't seem right to me that people are using RAID 1+0, RAID 5+0, or RAID 6+0 instead of using a RAID with 3 or more parities (akin to RAID 6) because the latter has a better reliability given the ...
James Haigh's user avatar
4 votes
1 answer
577 views

Best way to RAID 4 x Intel SSD 910 for PostgreSQL

I have a Linux (debian/ubuntu) server with 4 x Intel SSD 910 800GB pcie that I need to RAID together. The biggest problem with these card is that they give you 4x200GB drives that you cant hardware-...
Linus's user avatar
  • 41
6 votes
2 answers
3k views

MD RAID sector repair

This article states that RAID controllers are smart about unrecoverable read errors, and try to rewrite such sectors with the redundancy of the component drives. If the sector is bad, the disk's ...
Halfgaar's user avatar
  • 8,234
1 vote
1 answer
490 views

Force server to use all resources for resync

I need to resync my RAID and noticed that it isn't a big consumer. I have booted my system with the Rescue CD and started the resync. Looking at top it seems that the processes doesn't take much ...
CSchulz's user avatar
  • 243
1 vote
1 answer
2k views

Software-RAID with ext4 but without 64bit support

last year I set up a Software-RAID5 with 5x3TB yielding 12TB of usable capacity. Just today, needing more storage, I have finished growing the RAID to two more 3TB disks: Personalities : [linear] [...
Frederic Beister's user avatar
0 votes
1 answer
145 views

Raid1+0: create stripe over two /dev/mdx on partition or not?

Given that I haven't found a way to define how a Raid10 is created with mdadm, i went the Raid1+0 solution. How to display/define Mirror/Stripping pairs with mdadm mdadm --create /dev/md0 --level=1 -...
Chris's user avatar
  • 104
1 vote
1 answer
1k views

How to display/define Mirror/Stripping pairs with mdadm

I want to make a standard linux software Raid10 over 4 HDD. The server has 4HDDs, 2 pairs from different vendors in order to avoid batch problems. I want to have the mirror over two different Vendors,...
Chris's user avatar
  • 104
3 votes
2 answers
2k views

md raid1 reading from one disk only

I have two identical HDD in a linux software raid 1. I observed a mostly reading load on this raid device, with the process showing mostly iowait. iotop shows about 75% disk utilisation overall. If I ...
michael's user avatar
  • 31
0 votes
1 answer
611 views

System wont boot from degraded RAID6

I have a Debian Wheezy with 3 Partitions as RAID6. MD0 is for Root and OS, MD1 is for SWAP and MD2 for Files. While copy files to MD2 the system reports kernel panic and halts. I have had shutdown on ...
Sunghost's user avatar
5 votes
1 answer
672 views

reusing existing RAIDs on preseeded installation

I'm trying to automate the reinstallation process of existing Ubuntu installations. Partition layout: md0( raid1, /dev/sda1#/dev/sdb1 ) - swap (2G) md1( raid1, /dev/sda2#/dev/sdb2 ) - / (20G) md2( ...
Frank's user avatar
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