Questions tagged [mdadm]

A linux utility used to manage software RAID devices.

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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 ...
Crash Override's user avatar
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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 ...
Crash Override's user avatar
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1 answer
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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,...
Alexandre Barth's user avatar
4 votes
1 answer
3k views

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 ...
schweik's user avatar
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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 ...
mailoo95's user avatar
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548 views

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 ...
warbaque's user avatar
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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 ...
SVH's user avatar
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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 ...
Vincent Saelzler's user avatar
1 vote
1 answer
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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 ...
NON's user avatar
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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 ...
NON's user avatar
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How to convert LVM on MDADM RAID1 on two MBR partitioned drives to GPT without data loss

I have an Ubuntu 18.04 LTS Server with two 3TB Fujitsu SATA disks with MBR partition tables. Output from fdisk -l and lsblk is shown below : sudo fdisk -l /dev/sd[ab] Disk /dev/sda: 2,7 TiB, ...
storestyggeulv's user avatar
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1 answer
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Partition of mdadm raid0 array passed through to win10 20H2 via virto driver is suddenly lost. How can I figure out why?

I have checked the logs. System has been working for a month then suddenly they could not see the drive on network. It is a linux file server with a virtual windows on top of it ... Virtual windows ...
Gediz GÜRSU's user avatar
6 votes
1 answer
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mdcheck hangs when attempting to stop check

I have a raid5 array that has a check run on it once a month. It is configured so that the check runs for 6 hours from 01:00 and then stops. The following nights it will resume the check for another 6 ...
Paranoid's user avatar
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Creative solution for a crippled zpool (aka help a dying raid to survive for 1-2 weeks)

I have a ZFS RAIDZ-7 made by 8x4TB on a Proxmox 6 (linux kernel version: 5.4.78-2-pve, openZFS version: 0.8.5-pve1). An unfortunate astral conjunction force me to remove 3 disk from my RAIDZ. In ...
Steve81's user avatar
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Can iostat output show mismatched read data for mdadm raid5 array?

I'm trying to understand this iostat output: tps kB_read/s kB_wrtn/s kB_dscd/s kB_read kB_wrtn kB_dscd Device 500.30 58.9M 19.4k 0.0k 329.1G ...
JoeSlav's user avatar
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How does mdadm decide which disk to read from in mirrored arrays?

What exactly is the logic used to decide which block to read from diskA vs diskB in a mirrored array? Thanks
JoeSlav's user avatar
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Raid 5 is brocken after replace a disk

My server mailed me that one of my disks failed to read a block. So I decide to replace it before it failed completely. I added a new disk and replace the failing one. sudo mdadm --manage /dev/md0 --...
CordlessWool's user avatar
-1 votes
1 answer
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mount: /dev/md0: can't read superblock

I have a Raid 5 with 4 disk and is not working, I can't detect what disk is failing for replacement Could you help me? Thanks in advance Here is some information root@debian:~# mount /dev/md0 /mnt/ ...
Daniel Segovia's user avatar
1 vote
1 answer
277 views

Moving raid array from USB to SATA

I have a raid 1 array of two 2TB drives which I set up a while ago, both of them were connected through a sata->usb adapter (external HDD cases). Now I moved them into a proper PC but mdadm does ...
strokeberry's user avatar
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1 answer
644 views

After Reboot Ubuntu 20.04 - RAID10 goes INACTIVE

I installed RAID 10 on a fresh Ubuntu 20.04 By the Following commands: 1. mdadm --examine /dev/sdc /dev/sdd /dev/sde /dev/sdf sudo parted /dev/sdc mklabel gpt sudo parted /dev/sdd mklabel gpt sudo ...
Mitra's user avatar
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From mdadm raid to LVM (raid or mirror) decisions and how to monitor

We are migrating some server from linux raids (0 and 1) to LVM with stripe or mirrors. At the moment our systems are mainly configured something like | /tmp - /home - /others |------------------------...
luison's user avatar
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How is 'mdadm' stopped from doing an auto scan at startup?

Debian 10 VM has no software based RAID config, neither is there any intention of creating a software based (mdadm) RAID array. mdadm is installed purely as a dependency for cockpit-storaged mdadm ...
Peek's user avatar
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4 votes
1 answer
535 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
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1 answer
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mdadm - Attempted to move raid array to new system, superblocks gone?

I attempted to move a mdadm raid 1 array to a different system this evening. I took the 2 SSDs out of one system and put them in another, then booted that system. I opened gparted to check what the ...
user3728501's user avatar
5 votes
4 answers
6k views

How to change the file system of a partition in a RAID 1?

First, sorry if the question has already been asked and correctly answered, I did not find anything that satisfies me. I rent a dedicated machine in a datacenter, the machine run with a Debian 10 and ...
Taine's user avatar
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7 votes
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2k views

Write performance is 5 times worse with LUKS on top of mdadm RAID10 than without LUKS

I have servers with many NVMe disks. I am testing disk performance with fio using the following: fio --name=asdf --rw=randwrite --direct=1 --ioengine=libaio --bs=16k --numjobs=8 --size=10G --runtime=...
tacos_tacos_tacos's user avatar
1 vote
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188 views

Debian 10: mdadm raid superblocks "dissappear" after reboot?

I'm very confused by some issues I'm having with a raid setup with mdadm. I have a Debian 10 system, which I installed a KVM VM on, to use as a NAS server. I had problems with the raid superblocks ...
user3728501's user avatar
1 vote
2 answers
218 views

mdadm RAID5 array recovery stops without SCSI errors

I have an md-based RAID5 array which has been working without issue for about 2 years. Yesterday I've had spontaneous disk and/or PHY resets on one disk (but not actual read errors). md marked the ...
Anton Tykhyy's user avatar
0 votes
1 answer
282 views

Increase space by growing mdadm RAID10 from 4 to 6 (and more)

I'm running Centos 7.8 with mdadm v4.1 I have 4 NVMe (3.2TB each) configured in a RAID 10, so 50% usable space (6.4TB): Personalities : [raid10] md0 : active raid10 nvme5n1p16 nvme4n1p15 nvme0n1p1[4] ...
Bastien974's user avatar
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Possible solutions for Linux mdadm "raid5" over devices with different sizes?

I have server with 5 disks of 4TB, 2 with 8TB, and 1 10TB. I'd like to bundle them all together into Raid5/Raid6. As far as I understand one cannot do it nicely with disks of varying sizes. But I ...
eijeze's user avatar
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0 answers
420 views

mdadm RAID 10 filesystem corruption -- recoverable?

PROBLEM: I had a degraded disk in my RAID 10 array which I created using mdadm. I first removed the disk, replaced it with a new one, but when I rebuilt, I got an error saying it couldn't detect the ...
user3787902's user avatar
1 vote
5 answers
2k views

Added 4Tb HDD to Iomega IX2-200 but cannot extend the volume

I have a Iomega IX2-200 which came with 2Tb (1.8Tb usable) space. It has two disks set up as RAID1. I am trying to upgrade this to 4Tb disks. So far this is the process I have followed: Remove the ...
TenG's user avatar
  • 153
1 vote
2 answers
1k views

MDADM RAID-1 "not large enough to join array" on identical partition tables

I have two disks with identical partition tables (sudo sfdisk -d /dev/sda | sudo sfdisk /dev/sdb) that mdadm refuses to merge as a RAID-1 array. $ sudo mdadm --manage /dev/md0 --add /dev/sdb1 mdadm: /...
Suuuehgi's user avatar
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Virtual disks raid 10 array with ramdisk cache using bcache

I was trying to simulate a scenario with mdadm and bcache. I created 4 raw img files using qemu-img. I have created raid 10 using mdadm and created tmpfs on /mnt/ramdisk and created a raw ramdisk.img ...
Gediz GÜRSU's user avatar
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1k views

Using Intel fakeraid (imsm) on Linux - can I move the drives to a new server?

I'm using Dell Precision T3610 towers as Linux servers for various applications. These have Intel "Rapid Storage Technology" controllers onboard, with a rudimentary RAID functionality, ...
wes's user avatar
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0 votes
4 answers
1k views

Using mdadm - RAID1 array doesn't mirror other disk

Currently I am building a nextcloud server on Ubuntu 20.04. I got one disk for the OS to run on a 320GB harddisk. And I want the data directory to be in a raid1 array, because if one drive fails we ...
Mike milkshake's user avatar
2 votes
1 answer
5k views

Recommended approach for booting from Linux software RAID for redundancy

I am looking for the recommended approach to setting up software RAID (using mdadm) on Centos 8 to provide redundancy. In my setup I have 4 identical disks, but I assume the answer should also be ...
maloo's user avatar
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0 answers
215 views

Is it possible to send mdadm alerts using s-nail instead of postfix?

I run a mailcow server. I am able to send mail using s-nail from the terminal. I'd like to tell mdadm to just use that when sending email alerts, but when I run mdadm --monitor --scan --test -1, it ...
Giant Frog's user avatar
1 vote
1 answer
188 views

How to take backups resilient to data corruption , fast and reliable on Linux? [closed]

I need a resilient backup solution. I was using tar with pigz, however I am afraid of tar.gz corruption and losing data. Projects are between 4TB - 25TB of data for each project folder. We are talking ...
Gediz GÜRSU's user avatar
1 vote
1 answer
763 views

Very bad write speed on mdadm RAID1 with SSDs

I have two Samsung 860 QVO in RAID1 with mdadm. The write speed of a single disc is around 450MB/s. I reach a maximum of 70MB/s on the RAID 1. The reading speed is normal. xfs is used as the file ...
DerFlo129's user avatar
2 votes
0 answers
337 views

mdadm alerts configuration

I have a dedicated server in OVH. mdadm is installed and configured automatically, but I need configure scans and alerts. I checked some guides in internet but I'm not safe that this is the correct ...
MindServer's user avatar
1 vote
1 answer
2k views

How can I configure Smartmontools in a server with SSD NVMe?

I have server with two SSD NVMe in RAID1. This server have CloudLinux and cPanel, and he installed automatically Smartmontools. What command I need use for Smartmontools monitorize the SSD?: -This?: ...
MindServer's user avatar
1 vote
2 answers
271 views

Why Megaraid-sas and mdadm Raid 1+0 = Raid 10 Slow actual read speeds?

One of raid cards were giving multibit ecc ram module failure , thats why I am moving 60TB of data from one server to another ... Getting 60-100 Mb/s read speeds 3 Megaraid sas raid1 s 8+8+6 x 10TB ...
Gediz GÜRSU's user avatar
0 votes
0 answers
161 views

Folder in Ubuntu Became a File and the other Show Question Mark in Owner/Group

I encountered a very weird issue, appreciate if someone could help. One of my folder stored in a LVM2 XFS filesystem (mdadm RAID6), silently became a file and a folder showing question mark on both ...
teclinux's user avatar
0 votes
2 answers
1k views

how to get disks on a PERC H310 visible again

My setup : small home server with Asrock H67M-ITX, CPU : i3-2120T, PERC H310 RAID with 7 disks all passthrough (I use MDADM for the raid functionality). The system (Ubuntu 20.04) is on a SSD connected ...
Memes's user avatar
  • 408
1 vote
0 answers
223 views

RAID 5 reshape halted after hardware failure, tried to add disk again but, now it is added as spare

I have a 4 disk RAID5 (at a system with centos7). Space was all used up, so decided to add another disk and grow the array. So purchased a SATA card, added it to the machine and added disk on it. Then ...
Sandesh Wanjari's user avatar
4 votes
0 answers
347 views

Rebooted Ubuntu, Raid6 degraded, Raid5 ok [closed]

Boot Drive is a WD 1TB SSD running Ubuntu 18.04 LTS... I have 2 arrays running off 1 LSI Card... 16 x 8tb IronWolf inside a RaidMachine (Raid 6) [my main data] 11 x 10tb Exos inside a SuperMicro (Raid ...
PerryCS's user avatar
  • 151
4 votes
1 answer
373 views

Struggling to grow my physical VDO size after MD grow

I'm hitting a bit of a brick wall here with vdo growPhysical -n pool. I've recently replaced my 3TB HDD's with 4TB HDD's in an md RAID5 array, which is now showing the correct capacity (8TB) but not ...
mcmeeking's user avatar
0 votes
1 answer
646 views

SMART failure of a 4 disk software RAID10, mdadm, 2 drives show REMOVED state

Running Fedora 32 connected to a 4-port e-sata. One of the drives is clearly failing, with this message in the logs: smartd[1169]: Device: /dev/sdd [SAT], FAILED SMART self-check. BACK UP DATA NOW! ...
RobbieTheK's user avatar
1 vote
1 answer
1k views

How to interpret conflicting status data between `smartctl` and `mdadm`?

I have a HDD which is a member of a RAID10 array. smartctl and mdadm give me conflicting indications of its status. smartctl claims that the disk is FAILED: $ sudo smartctl -H /dev/sdf smartctl 7.0 ...
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