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Questions tagged [mdadm]

A linux utility used to manage software RAID devices.

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Less painful way to resize/rearrange RAID1 backwards with mdadm

Got the following scenario in a two-disk RAID1 (mdadm) Debian-based server (no LVM involved): Partitions (same for mirror /dev/sdb): Unassigned space (formerly /dev/sda1 with Windows). /dev/sda2 ...
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15 views

smartd reporting intentionaly removed disk

Iam monitoring my SW RAID on server using smartd, the problem is i removed failed disk. The disk was already put out of any RAID and hotswap was put on his place. There fore i just simply took the ...
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2answers
33 views

PowerEdge T610 H700 controller upgrade

I have a PowerEdge T610 server with Perc H700 RAID controller. I wanna use the controller for non-raid, but I read some posts and the H700 controller doesn't support the non-raid operation. The ...
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1answer
42 views

Uneven disk load with mdadm RAID5 and ext4 filesystem with journal

Recently I created a RAID5 with mdadm: mdadm --create /dev/md0 -l 5 -n 4 -c 512 /dev/sdb /dev/sdc /dev/sdd /dev/sde The usual tuning to speed up the initial sync: echo 32768 > /sys/block/md0/md/...
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36 views

mdadm hardware raid-5 broken after dist-upgrade

We have intel raid-5 in motherboard, which was assembled in ubuntu as well and mounted as home in fstab. I read later somewhere I shouldn't use hardware raid in ubuntu. However it was working. But, ...
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27 views

How to setup bootable RAID 0 on remote server

I have a remote server with 2 identical 500Gb SSD, sda and sdb. A rescue mode is also available from the cloud provider's interface. How to get Debian installed on a bootable RAID 0? I understand I ...
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12 views

kpartx does not enumerate partitions properly on Software RAID

When I boot my system, partitions on a software raid group are not being enumerated automatically. As a temporary fix I added the instruction break=mount in grub, so I can run manually kpartx -a /dev/...
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34 views

Messy RAID Array creation Needs Clean-up

I'd like some help to understand problems I am currently experiencing with a RAID 1 Array, created from Intel RSTe and managed with mdadm. Overall RAID 1 Configuration Both /dev/sda and /dev/sdb are ...
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3answers
71 views

Missing mdam RAID1 array during scan

I have built a new server (Ubuntu 18.04.1) with 4 HDD. My plan is to use RAID1 overall and came up with this layout after investigation: sda, sdb four primary partitions (all as fd) with sda1/sdb1 ...
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1answer
15 views

mdadm RAID configuration changes disk sdXX naming randomly on reboot

I have an issue with software raid i build over 2 expanders with disks loaded as JBOD. After every reboot of server, the naming of virtual drives changes and also the array numbers and logic are ...
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62 views

Debian software raid 50

I was given task to build large SW RAID 50 array on debian 9. Since now i was using mainly HW controllers to do so, which managed a lot of by them selfs. I have few question now I managed to build ...
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RAID6 failed instantly and switched to RAID0 - any chance to rescue?

I´m running a server ob Ubuntu 16.04. Data storage on this system uses a lvm on top of a software raid 6 whereas the os is installed on a separate raid 1 with lvm. The raid 6 is built up of 7 ...
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1answer
36 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 --...
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1answer
119 views

Is it possible to convert RAID1 to RAID0 without system reinstalation?

I bought the E3-SSD-3-32 server from the SoYouStart offer. There is a 3x120 GB SSD drive. Unfortunately, after some time, there was a lack of disk space. Is there any way to convert RAID1 to RAID0? ...
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3answers
379 views

Disabling ext4 write barriers when using an external journal

I'm currently experimenting with different ways of improving write speeds to a fairly large, rotating disk-based, software-raid (mdadm) array on Debian using fast NVMe devices. I found that using a ...
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103 views

Resize AWS EBS raid0

I've got an AWS raid0 array that I'm struggling to resize. The underlying EBS volumes have been increased in size, but I'm not able to re-size the array to resize the FS. I've tried using mdadm and ...
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1answer
122 views

Recover RAID 1 after unclean unmount

I have two drives in my desktop in RAID 1. My computer locked up on me yesterday, so I used SysRq REISUB for a "safe" restart. When the machine booted back up, I realized there was no data on my RAID ...
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1answer
481 views

Why does mdadm --zero-superblock preserve file system information?

I have two hard drive partitions, which I have combined into a RAID1 using mdadm, and created an ext4 filesystem on the resulting device. When I mdadm --zero-superblock the two partitions, and re-...
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20 views

how to recreate a raid 1 array from a (failed) drive

A friend (yes, not me) had a RAID1 array where he didn't notice that both drives went massively bad (I suspect the computer was dropped or otherwise abused). I'm trying to recover what I can from the ...
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45 views

Recover data from a Linux software RAID1

I get a new customer with a failed old server (it does not boot anymore because of a failed CPU). Unfortunately the customer does not have a backup and I am trying to recover data from the hard ...
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215 views

linux how to run badblocks for software raid (mdadm)

For a normal HDD partition, we run badblocks on HDD partition before creating the file system, like the following: badblocks -o filename /dev/sda1 mkfs.XXX -l filename /dev/sda1 Note: XXX can be ...
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65 views

md RAID1 / ext4fs corrupting during nightly SMART self-test

I'm having this strange issue where my root-mount filesystem is terminally corrupted and auto remounted read-only seconds after a nightly S.M.A.R.T. short test begins. The filesystem is ext4 on top of ...
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1answer
178 views

RAID1 mdadm, automatically fail a drive and avoid a read-only file-system?

I am managing a server with two solid state drives configured in mdadm RAID1. The server is running RHEL6 with an ext4 filesystem. This evening the server went offline shortly after nightly backups ...
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1answer
37 views

How to create software raid on working ubuntu server with gpt?

i have this structure of hdd on my server: fdisk -l Disk /dev/sda: 2.7 TiB, 3000592982016 bytes, 5860533168 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / ...
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256 views

mdadm array disappears after system reboot

I have created an md array like so: mdadm --create /dev/md0 --level=0 --raid-devices=2 /dev/sdc /dev/sdd Then I used the resulting device in a ZFS pool: zpool attach tank sdb md0 That worked great....
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1answer
30 views

Debian Jessie RAID6 recovery mdadm

I have a Debian Jessie box that lost the RAID volume that had the OS, so I booted Live USB to try to recover the attached SAS controlled external drive bay which has my data RAID6 and it sees 3 of the ...
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1answer
44 views

Do more mirrors in raid 1 reduce the likelihood of spit-brain failures?

I'm setting up a server, and my predecessor had a habit of setting up multiple RAID 1s with only 2 disks, which eventually resulted in split-brain situations which were difficult to recover from. ...
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285 views

Creating a RAID1 mdadm array `--bitmap=none` VS `--consistency-policy=resync`?

I am on CentOS7 with mdadm-4.0-5. I have been experimenting with creating a RAID1 array on 2 SSD disks. The disks are not very large (~120G) so the rebuild time in case of failure should be very ...
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2answers
148 views

Cloning multiple SATA drives using dd with the assistance of software RAID1

So, I clone lots of Windows-based NTFS drives from images each day and I'm halfway through a project that could potentially help me and others to speed up this process dramatically. I currently have ...
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0answers
99 views

mdadm/ext4 chunk size on raid 1

Sorry for my noob question. I have a raid 1 system on mdadm in Debian, with the resulting partition formatted as ext4. Looking at the resulting share in Windows, it reports: Size: 618GB Size on disk:...
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Is it OK to prepare drives in mdadm RAID in LinuxMint live and then run CentOS7 installer?

I am planning to setup a CentOS7 server with software RAID. Since the CentOS7 installer isn't particularly good at preparing the disks, I wonder if it would be OK to boot up a LinuxMint 18 live, do ...
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1answer
744 views

TRIM issues with software RAID1 (mdadm) on two different SSDs (size and manufacturer)

I plan to do a server with 2 SSDs in RAID1 (for OS and boot) and 3 HDDs in RAID5 (for data). All Linux (CentOS7) with mdadm. We have in the office 2 leftover SSDs, but they are from different ...
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2answers
53 views

Recover files from one of three mdadm RAID5 disks

I have lost 2 of 3 mdadm RAID5 disks. How can i recover whatever files are available on the remaining one disk? Sundeep
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41 views

Will my reshape result in an unrecoverable array?

I was adding an additional new drive to 4 drive raid 5 mdadm array. During the process that drive was marked as faulty, along with one of the original 4 drives. Previously to this the array had ...
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102 views

Expand mdadm array size without losing data on RAID 1

I have a mdadm raid 1 (size: 2TB) with 2 disks of 3TB. I'm using almost all of the space of the mdadm array so I'm considering expanding. However, I don't want to lose my data (of course :) ) As far ...
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104 views

7-disk RAID 5 working with only one disk? Bug?

I've got a 7-disk RAID-5 (3TB each), on a CentOS 5.5 box. Today I was doing regular checkups on my system and found this weird bug(?): How is this possible? This filesystem is formatted as XFS and ...
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582 views

Troubleshooting `Buffer I/O error` on software-raid/md-device

I've got a RAID-5 mdadm array that reliably causes Buffer I/O error on dev md0, logical block 1598030208, async page read to be written do dmesg when reading that block. Of course, the read also ...
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114 views

raid problems after power outage

I was in the middle of copying data to a raid5 from a raid 1 when the power went out. Initially, I figured the raid was lost, so I zeroed the super-blocks. fdisked all the drives in the raid 5 and ...
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2answers
60 views

Raid 1 from already initialized disk

I have 4TB disk (A) with data in it. Now I've bought a new 4TB disk (B), and I want to start a RAID1 so that B becomes the mirror of A, without loosing data on A. I'm under linux with mdadm tool. The ...
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1answer
59 views

Mixing mdadm RAID with partially power loss protected SSDs

I have created a mdadm RAID 10 with 4 SSDs. 2 of those SSDs are consumer models and does not have the power loss data protection feature. At the RAID creation i have put 1 SSD with power protection ...
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1answer
182 views

Missing raid device in /dev/

I have two sata disks: /dev/sda and /dev/sdb. I have 4 partitions: /dev/sd[ab]1 /boot /dev/sd[ab]2 swap /dev/sd[ab]3 / /dev/sd[ab]4 /home And all of them are in raid1. Raid is working fine. Here is ...
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62 views

mdadm raid5 disk disabled, state clean, smart passed

i'm running a raid5 array with 5 disks. One disk got disabled. dmesg : ... [Tue Dec 5 01:02:08 2017] md/raid:md0: read error NOT corrected!! (sector 15263288 on sdb1). [Tue Dec 5 01:02:50 2017] ...
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1answer
56 views

Reasons for Linux to exclude a disk from the RAID10 array (degrade it) except for physical failure

I would like to understand the set of conditions on which Linux considers a drive really faulty, excludes it from array and considers RAID10 array degraded. As I know, neither SMART self-check ...
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1answer
238 views

What are RAID 1/10 mismatch_cnt > 0 causes except for swap file?

Two of four of my servers currently have mismatch_cnt about 40000 and that worries me. We are using RAID10 setup. Manual states, that However on RAID1 and RAID10 it is possible for software issues ...
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1answer
154 views

RAID6 resync with fast writes but slow reads

I'm using Debian Jessie. # uname -a Linux host 4.9.0-0.bpo.3-amd64 #1 SMP Debian 4.9.30-2+deb9u5~bpo8+1 (2017-09-28) x86_64 GNU/Linux And have setup a RAID6. # cat /proc/mdstat Personalities : [...
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1answer
44 views

Enable new disk in raid

I had a server with 2 disks in a raid and one of them failed. Called the provider and had them change the disk. After a reboot I still see only one disk: cat /proc/mdstat Personalities : [raid1] [...
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1answer
147 views

GParted shows Raid1 partition as Ext4, how can I correct that?

As I've recently bought some extra disks to store my VM disks redundantly, hoping for some increased read performance and redundancy in case drives fail, I started building a RAID array. I've ...
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1answer
108 views

mdadm - Convert multiple md members from RAID 5 to RAID 6

I've been looking for resources to manage a migration of several md members from RAID 5 to RAID 6 using mdadm. Using this handy guide, http://www.ewams.net/?date=2013/05/02&view=...
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1answer
120 views

MDADM RAID1 Re-assembly - Non-destructive Method?

After a system reboot, my MDADM array suddenly showed very old (more than a year) data. I assume that one of the disks (sdd1) has been offline for most of that time, and after the reboot I am now ...
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568 views

mdadm marks hdd faulty even though it's in pristine health?

I have my custom NAS configured to spin down drives after 20 minutes of idle. Just now I checked /proc/mdstat and noticed a drive was marked as failed, however SMART shows the drive to be in very ...