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Questions tagged [mdadm]

A linux utility used to manage software RAID devices.

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40 views

Can I Increase raid 1 capacity by changing to raid 5?

My initial raid setup was 2x2TB RAID 1 using mdadm. I have bought a 3rd 2TB drive in the hopes to upgrade the RAID's total capacity to 4 TB using mdadm. I have already run the following two ...
3
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0answers
28 views

Hybrid RAID (SDD+HDD) gives unexpected results

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 (/...
4
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1answer
35 views

Shrink MDADM Raid 5 containing LVM

The plan: I've been growing a Raid5 array in a personal server for some years, and the time has come to move to something more suited to this application. I've accumulated 6x 8tb drives containing ...
3
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1answer
53 views

How to check/fix nvme health?

I'm running debian stable with a 2 x nvme Raid 1. Here is the hardware/hoster it's running on https://www.hetzner.com/dedicated-rootserver/ex62-nvme?country=us Almost every second day mdadm monitoring ...
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0answers
24 views

Server hangs up while building array

my goal I want to build a raid5 with 3 disks that I partitioned into 6 partitions. what I did so far I have 3 disks ST8000VN0022 (seagate iron wolf). I created 6 partitions on each of those disks. ...
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1answer
28 views

RAID 5 crash… trying to save what I can [closed]

I have a QNAP server with 8 disks. I have 2 backup/extra disks that are not in use. (I had the money an knew eventually the running ones would need replaced) The full array was across the 8 disks @6TB ...
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0answers
62 views

State of LVM raid compared to mdadm

LVM and mdadm / dmraid are both offering software RAID functionality on Linux. This is pretty much a follow-up post to this question from 2014. Back then, @derobert recommends to prefer mdadm over LVM ...
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45 views

Disk utilization on mdadm raid 5 is 100% even though none of the member disks is at 100%

I am currently confused about the disk utilisation of one of my machines. The setup: I have a machine containing 4 2TB HDDs. For those HDDs I used mdadm to configure a RAID 5 (called md2) On MD2, I ...
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0answers
60 views

MDADM can't automount existing RAID1 array

I recently reformatted my system and cannot get my RAID 1 array to load on boot. Would appreciate some help figuring out why this is. Using ubuntu 14 with MDADM. Its a very simple RAID1 array ...
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1answer
55 views

mdadm RAID 1 partitions on sda1 and sdb1

Quick background: I have a RAID 1 array, created using mdadm. Both drives are hard-drives. The RAID array is called md127. There are 3 partitions in this RAID array: 20G for /var, 20G for /opt and 891....
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0answers
83 views

Reducing disks from a RAID5 mdadm with LVM

Checking a system, I found a server with 12 4TB drives in Raid5, with LVM on top. Single VG, single PV, and a few LGs that wouldn't need more than 6TB of space (currently only 4TB). Read speed is no ...
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1answer
79 views

Why isn't a disconnected and then reconnected mdadm RAID1 disk automatically re-attached and re-sync?

I'm doing the following test with Debian 9 under Hyper-V: I have two (virtual) disks, each with one partition, and /dev/md0 defined as RAID1 of /dev/sda1 and /dev/sdb1. The root EXT4 file system ...
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18 views

ix2-dl soho software won't mount disks

TL;DR the web gui and event viewer as well as soho.log don't actually print when mounting disks. It mounted itself eventually after a few days of uptime. No log message, no warnings or errors. No idea ...
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1answer
178 views

Debian mdadm: No devices listed in conf file were found

My Debian sid machine had been booting kernel 4.13 from a raid array for several months without issue. 2 days ago I upgraded the platform and now booting fails like this: Additionally, the initramfs ...
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1answer
426 views

SW RAID-1 grub-install

I just changed /sda system disk in SW RAID using following steps, simply put: sfdisk -d /dev/sdb | sfdisk /dev/sda mdadm --manage /dev/md0 --add /dev/sda2 Now disk is initializing chcked by: cat /...
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0answers
71 views

mdadm - are there any downsides of mixing 512 B and 4 kB logical sector size disks in RAID 1 or RAID 5/6?

I have a mdadm RAID 1 and RAID 6 setup with 8 TB disks which are using 4 kB physical sector size but 512 B logical sector size. I want to add more 8 TB disks to these arrays and the way I usually do ...
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2answers
74 views

Persistence of home directory after deleting all partitions and reinstalling:

I was running Ubuntu Server on a mdadm RAID1 volume, and I ran into some problems so I decided to just do a clean install. I booted with Gparted, stopped the mdadm array, and ran --zero-superblock ...
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2answers
134 views

USB hard drive I/O slow speeds

I have several Mediasonic ProBox HF2-SU3S2 with 4 drives - all with the same symptoms - extremely slow I/O (at best, about 10MB/s write). Each unit is configured with a software RAID 5 using mdadm ...
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0answers
105 views

Coping with bad sectors on RAID disk

I have a RAID 1 of 2 hard drives managed with mdadm. Today, one of them failed. I figured out that this is because of bad sectors in /dev/sdb. According to badblocks, these sectors are affected: 1028, ...
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0answers
30 views

Cannot add partition back to RAID 1

I run an mdadm RAID 1 on my Raspberry Pi. The USB cables to the two hard disks (especially to /dev/sda) seem to provide somewhat loose connections or someone touches them. They are right next to the ...
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0answers
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HDD works with onboard SATA connectors but not behind LSI 9201-16e. Why is that? [closed]

I'm trying to build a NAS from scrap hardware I had laying around. It's current specs are: Motherboard: P5N32-E SLI Plus (latest bios as of writing) RAM: 3 GB generic DDR2 OS Storage: 80 GB Maxtor ...
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3answers
976 views

BTRFS Raid 1 vs. MDADM Raid 1

I'm currently in the process of setting up a NAS system mainly for backing up my computer and probably also for streaming media files to my devices. For these purposes, I decided to use ...
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1answer
37 views

Raid with faulty spare reference but with all physical devices good

I'm seeing sdt[6](F) but I cant remove or set it as failed device # mdadm /dev/md126 --fail /dev/sdt --remove /dev/sdt mdadm: cannot find /dev/sdt: No such file or directory /dev/sdt does not exist ...
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142 views

recover data from former RAID 1 drive

I had a RAID1 setup (md0), mirroring two 2TB drives (sdb, sdc). When trying to remove the RAID to use the disks individually with the data on them, I ran mdadm --stop /dev/md0 mdadm --zero-superblock ...
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1answer
119 views

How to set timeout for the systemd start job “dev-md125.device” (mdadm)

I've setup a RAID1 device with mdadm on CentOS 7. The system boots fine when both disks are inserted but hangs when there is only one. The error occurs at boot with the following message from systemd:...
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1answer
419 views

Add linux md raid write journal to and existing array

I have a raid5 array with quite large disks, so reconstruction is really slow in case of a power outage. Thankfully, there is the --write-journal option for linux md raid. The man page lists the --...
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1answer
57 views

Raid1 using Mdadm setup post-install Fedora

I have never messed with Raid before in Linux but while installing Fedora Desktop I tried to setup Raid1. All seemed well at first but alas I look to have failed. So here is how my disks came out. (...
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1answer
155 views

mdadm RAID comes up inactive each reboot

I have a mdadm software RAID6 that comes up inactive upon each reboot. All its disk are present but shown as spares. How do I make it start operational (active)? This is it's state after reboot: cat ...
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1answer
60 views

Build RAID 5 with mdadm and 1 disk with data

I have 3 exactly the same drives (4tb ironwolf) where i would like to make a raid-5 with using MDADM for a small degree of data security. Now the problem is, 1 drive is filled with data which i am ...
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1answer
228 views

linux “mdadm --write-journal” and lvmcache - how do they relate?

In linux mdadm man page I saw the option "--write-journal". How does this relate to lvmcache as lvmcache is built on top of dm-cache? Are they different things or does lvmcache do something like "--...
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2answers
762 views

How does write cache work with a filesystem spanning disks with different speeds?

On a modern Linux system with multiple disks and a software RAID spanning both slow (HDD) and fast (SSD) drives, how are writes to the filesystem cached? For md-raid RAID1 the array can be configured ...
2
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2answers
167 views

How many arrays can be created with mdadm?

For an experiment purposes, I need as many disks in a single system as possible. Since I have only six spare disks, I decided to partition them to 128 GPT partitions and create RAID0 array of one ...
1
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1answer
136 views

mdadm raid10 recovery - is this filesystem corrupted? Is it fixable?

Background: I had an Ubuntu Bionic system set up and running using 3x1tb disks. The disks were all partitioned with one circa 15gb partition and the remaining circa 983gb. 15gb partitions from two ...
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0answers
30 views

Can I enlarge a RAID partition?

I have an OpenSUSE 42.3 system with a RAID5 (mdadm) made out of four discs (2 2TB and 2 3TB). I'm growing the RAID by replacing the 2TB discs with larger ones. The 3TB discs have only 2TB partitions ...
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2answers
152 views

Rebuilding mdadm RAID 5 array with multiple failed drives

I had a 5 drive Raid5 array and I've had two drives fail. I have fresh drives to swap out, but when I'm trying to start it it complains '/dev/md/0 assembled from 3 drives - not enough to start the ...
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1answer
415 views

RAIDs disappearing on reboot (Centos 7.5)

I'm trying to create 4 RAID 0 disk arrays on my system running Centos 7.5 and have the RAIDs automount after a reboot. For some reason, only one of the RAIDs /dev/md0 is persistent between boots. The ...
2
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1answer
355 views

Extending RAID0 with `mdadm --create --assume-clean`?

I had a 1-disk RAID0 array that I created with a view of adding more disks to it eventually, that was working normally. I created it with (approximately): $ mdadm --create /dev/md0 --raid-devices=1 --...
2
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1answer
756 views

Backup existing mdadm array setup

I recently installed mdadm an set up a raid1 configuration involving 2 500GIO drives. Is there a way to backup a RAID configuration somewhere so I could re-load it using a single mdadm command in ...
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0answers
796 views

Unable to assemble existing RAID array with mdadm

I originally set up a RAID1 array on Windows with RST (not as a bootable disk). I recently started moving everything to xubuntu, so I tried mdadm on my xubuntu partition (dual boot). Installing and ...
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1answer
364 views

mdadm raid 1 how to remove raid and remove data offset to mount normally?

I have a disk that was in a mdadm raid1 with a btrfs partition. Now I want to use this partition without the raid stuff and mount it normally. I already zeroed the mdadm superblock, but now the ...
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1answer
265 views

Moving drives currently in software raid to LVM? [duplicate]

I have 3 drives currently set up in RAID 5 via mdadm. I just realized that I goofed and forgot to format them with LVM- is it possible to do this after RAID array creation without losing data?
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65 views

(Complicated) RAID hard drive issue

I have a (complicated) RAID hard drive issue: I have a Synology DS413j with 4 hds, hd 3 failed so I decided to replace them. The official support article says to replace them one by one, and being ...
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2answers
130 views

MDADM - adding a disk to RAID5 with slightly less sectors

Basically I have raid 5 with three disks that are 2TB each. I bought 2 extra 2TB drives however they are few sectors smaller on a newer model - old drives are no longer sold. When I issue /dev/md0 ...
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0answers
50 views

How to prevent spinning up standby drives on system shutdown?

I have an file archive server with 20+ hard drives attached to it. Since I don't access them very often, most drives are kept in the "standby" mode. This way, even though the server itself runs 24x7, ...
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1answer
82 views

Mounting an EXT4 partition that is marked as RAID 0xFD

I have one hard drive, with a GPT partition table and three partitions. One partition is SWAP. The other two partitions are marked as LINUX RAID 0xFD, but one of them should be an EXT4 file system. ...
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1answer
43 views

rebuilding mdadm raid5

I've dusted of a machine of which I want to repair an mdadm raid5 that I messed up. First the raid5 was 3 disks. A spare was added, just before one of the three started to fail. Spare one got used and ...
2
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1answer
228 views

What is the best way to explain this LVM output?

I bumped into the issue two days ago about RAID issue on my TS-251+ QNAP. I do not really bother the box until the problem comes. I explored details to find out what type of RAID, how RAID/LVM ...
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0answers
311 views

Can't run 'update-grub'

I've got some trouble with my Ubuntu-System: update-grub Generating grub configuration file ... grub-probe: error: disk `mduuid/c7ac5a8fef833db7b45d6c2ebb2e20e6,1' not found. But I'm still able to ...
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1answer
153 views

How to fix mdadm: inactive RAID1 arrays, after unplugging one of the drives in both cases?

TL;DR I need to read and write from / to 2 of my mdadm RAID1 arrays after unplugging one of the drives in both cases and commenting them out of /etc/mdadm/mdadm.conf + updating initramfs, of course. ...
2
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2answers
434 views

Slow Write Speed(<2 MB/s) on Unencrypted and LUKS Encrypted ext4 filesystems using mdadm Software RAID1 Debian 8 Dell PowerEdge T330 Server

We have installed Debian 8 on a new Dell PowerEdge T330, there are two partitions, / and /var, in a RAID1 array using mdadm. During testing the primary applications: mysql and tomcat were stopped. We ...