A linux utility used to manage software RAID devices.

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DegradedArray event on /dev/md1

This morning I got this message: This is an automatically generated mail message from mdadm running on A DegradedArray event had been detected on md device /dev/md1. Faithfully yours, etc. P.S. ...
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977 views

What are the advantages and disadvantages of constructing an mdam array from whole disks vs. partitions?

Let's say I've got six identical drives and I'm going to use them all in a RAID10,f2 array constructed using mdadm. I've always put a single partition on each disk and constructed the array from ...
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apt-get update mdadm scary warnings

Just ran an apt-get update on one of my dedicated servers to be left with a relatively scary warning: Processing triggers for initramfs-tools ... update-initramfs: Generating ...
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Slow md RAID-1 array

We have some problems with very slow disk response on our server. I checked iostat (iostat -d -x 30) and have some problems with its interpretation: Device: rrqm/s wrqm/s r/s w/s ...
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Can't resize2fs - combination of flex_bg and !resize_inode

I recently set up my first software raid with mdadm and after adding more disks to the raid I am unable to resize the filesystem to the full size of the raid. I created a single (~16TB) filesystem on ...
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988 views

Degraded RAID-5 array with lvm2 lost superblock and partition table

I have a RAID-5 array of 4x1TB hard disks with one lvm2 partition on Ubuntu Linux 10.04 LTS. One of the disks has failed. I have re-assembled the array without this failed disk but now mdadm --examine ...
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1answer
833 views

CentOS 6.5 mdadm Raid 1 - Kernel Panic during raid data check

I have a brand new CentOS 6.5 install with two (mounted to /mnt/data) 1tb Western Digital Black drives in raid 1 with mdadm, configured via the installer. Unfortunately every now and again the entire ...
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1answer
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mdadm+zfs vs mdadm+lvm

This may be a naive question since I'm new to this and I cannot find any results about mdadm+zfs, but after some testing it seems it might work: The use case is a server with RAID6 for some data that ...
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1answer
398 views

3 drives fell out of Raid6 mdadm - rebuilding?

i had an mdadm raid6 array with 13x1TB drives. Within 10 minutes 3 of these drives fell out of the array... we assume bad cable to the controller card and replaced, however now we need to get the ...
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1answer
620 views

Debian installation on software RAID (lilo.conf configuration)

Debian installation program has created lilo.conf: boot=/dev/md1 root=/dev/md1 raid-extra-boot=mbr-only But when i configure lilo i usually put these lines disk=/dev/md1 sectors=63 heads=255 ...
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Failed MDADM Array With Ext.4 Partition - “e2fsck: unable to set superblock flags on /dev/md0”

Had a power failure and now my mdadm array is having problems. sudo mdadm -D /dev/md0 [hodge@hodge-fs ~]$ sudo mdadm -D /dev/md0 /dev/md0: Version : 0.90 Creation Time : Sun ...
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72 views

Why is my HDD partition a character special device?

I have a bunch of old 1T disks with an mdadm array on them. They had been out of commission for awhile, but yesterday I slotted them into a server running an up to date Debian Jessie. Eventually I ...
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1answer
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Cannot install grub, segmentation fault, unable to identify filesystem, superfluous RAID member, found two disks with same index — Debian 7

A server was recently transported from location A to B, a long journey that took six months. Things have gone wrong due to nothing being labeled prior to shipment. Yes, I know --- it was done by ...
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1answer
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Resize openSUSE 12.3 GPT ext4 partitions in a RAID1 disk array

I have a software raid configured (/dev/md2) which has assigned the partitions sda3 and sdb3 from two 3TB disks (sda and sdb). The partition types are GPT not LVM and file system is ext4. Now, the ...
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1answer
537 views

EC2 disk goes to 100% util, but fine after reboot

We've been running some production services on Amazon EC2 for a while, using mainly t1.large and t1.xlarge instances (non-EBS). Every so often one of the attached (ephemeral disks) will get into a ...
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Linux RAID 1: How to make a secondary HD boot?

I have the following RAID 1 on a Centos 6.5 server: # cat /proc/mdstat Personalities : [raid1] md0 : active raid1 sdb1[3] 974713720 blocks super 1.0 [2/1] [_U] bitmap: 7/8 pages [28KB], ...
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2answers
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Mdadm won't create an array larger than 10TB

I have a server with six 4TB drives running Ubuntu 14.04 LTS. One of the drives is used for the system/OS I wanted to use the other 5 drives to get as close to 20TB of storage as possible It's a ...
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3answers
396 views

Degraded partition in RAID5 system

I've got a server running Debian Squeeze and a 3x 500 GB-drive RAID5 system which I haven't set up myself. When booting, the status of one partition in the RAID-array seems to be bad. md: ...
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1answer
637 views

mdadm RAID1 to RAID6

I've got a RAID1 array. I'm buying 4 more disks of equal size (they're the same model drives) and I'm trying to enumerate my options for a safe upgrade. Ideally they'll be one large ext3 volume. ...
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1answer
263 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 ...
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282 views

Does growing a RAID 5 destroy the data on the RAID?

For a linux software RAID using madadm, does adding a harddrive and growing onto the RAID, destroy the data that's already on the RAID or does it preserve everything?
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mdadm Boot Error, incrementally starting raid array Ubuntu SErver 14.04

i build a small Server with Ubuntu 14.04 for Samba, I has one SSD Drive (the ubuntu installation is on it) and 2 3TB SATA Disk, the sata disk are combined to a Raid 1 with mdadm. Now sometimes (no ...
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132 views

mdadm: Disk configuration by UUID

I want to create a soft RAID-5 and use UUIDs im the mdadm config file. So I have four disks with 1 partition each that spans the whole disk. But since the partitons don'5 have a filesystem, blkid does ...
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Raid 5 with 4 disks on Debian automatically creates a spare drive

I'm trying to to create a RAID 5 with 4x 2TB disks on Debian 6. I followed the instructions from: http://zackreed.me/articles/38-software-raid-5-in-debian-with-mdadm I created the raid with following ...
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Growing a RAID5 using mdadm with multiple drives?

I have a RAID5 array that consists of 3, 2TB drives. I want to add 2 more drives. The tutorials involve adding a single drive to an array, such as this: https://raid.wiki.kernel.org/index.php/Growing ...
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Is mdadm Raid-1 Over A Network File Share Possible?

I am using 64bit CentOS 5.5 I know it's possible to set up software RAID1 using mdadm using a physical hard disk and a RAM disk. Is it possible to set up software RAID1 with mdadm using a NFS mount ...
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Recover RAID-5 that was already running in degraded mode (lost a second disk)

this is silly, this has happened before and I figured out how to fix it and it was fine. I'm running 4 500GB SATA drives in a RAID-5 on Ubuntu 7.10 server. One of the disks failed (actually I think ...
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2answers
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mdadm stalls rebuilding a RAID5 array at 99.9%

I recently installed three new disks in my QNAP TS-412 NAS. These three new disks should be combined with the already present disk into a 4 disk RAID5 array, so I started the migration process. ...
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859 views

mdadm - Recovering a 'split' RAID1 array

I have two drives that used to be part of a single RAID1 volume but it appears that one of them went offline for some time, something I've noticed just now when I rebooted my system. I now seem to ...
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963 views

Linux Software RAID1 Rebuild Completes, but after reboot, its degraded again

I have been beating my head with an issue here, and I'm now turning to the internet for help. I have a system running Mandrake Linux, with the following configuration: /dev/hda - This is a IDE ...
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2answers
665 views

Reading off of MDADM drives after server died

I had a 2-drive RAID-1 array running on ubuntu, which I had forgotten about. The host I was running them on is now dead, leaving me with these two disks. How can I get data off of them? If I dump ...
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1answer
349 views

reshaping raid and growing raid

This is a two part question. 1) Can you reshape raid 5 to 6 with mdadm on linux (fairly sure you can, but cant get mdadm to accept it) 2) Can you do 1) while also growing the array in one go ?
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129 views

Is there any way to build a linux software raid system without all drives?

I'm building a raid1 (ok it will probably be a raid10,f2 but the difference with 2 drives... isn't much) system with 2 1TB drives. However, 1 of the drives I've ordered is bad so I'm RMA-ing it. I'm ...
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1answer
592 views

Linux Raid: mystical md_d device

I have a 64bit Ubuntu Jaunty server (kernel 2.6.28-17-server) installed on two SATA disks (sdc and sde) in a mirror RAID, this being my current raid configuration: cat /proc/mdstat Personalities : ...
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1answer
82 views

2 disk RAID5 Linux software array

(I've posted this on Serverfault as I suspect it a bit to technical for Superuser. If I'm wrong please move it where appropriate) I am remotely looking at a device which identifies as ReadyNAS ...
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882 views

mdadm failure detected on one partition

I received this rather nice email today suggesting one of the drives in a RAID1 array has failed. A Fail event had been detected on md device /dev/md4. It could be related to component device ...
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1answer
505 views

Software RAID1 ready to fail - How can I degrade manually?

I have a Centos 5.4 server in production with 2 drives in software RAID1. The last days /var/log/messages has a lot of messages, showing that one of the drives is ready to fail: Sep 23 00:48:38 ...
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945 views

How to diagnose intermittently slow raid data transfer rate?

I have an encrypted RAID6 set up on Centos 5.5. When I transfer a large 10gb file from the raid to my computer it will pause at around 4-5gb and again at 9gb. The data transfer drops from 25mb/sec to ...
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3answers
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Creating backup disk image of RAID 1 array (MDADM)

We have some servers that run in very harsh environments (research vessel) that need to have high-availability. We have software RAID 1 for some measure of resiliency, along with proper data backups ...
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1answer
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Linux Mdadm + LVM recovery

I recently reinstalled my Ubuntu server with 10.04, and am having trouble reactivating the LVM partition which houses all my non-critical data. /dev/sda, /dev/sdb, /dev/sdc, and /dev/sdd are all ...
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1answer
153 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 ...
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1answer
102 views

Reading /proc/mdstat

I just built my first raid5 yesterday (with 4 hds) and was reading about monitoring with /proc/mdstat. My understanding is an ideal dispaly with 4 drives should be [UUUU] however mine reads [UUU_]. ...
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Slow disk I/O in KVM with LVM and md raid5

I have been battling with a kvm setup under debian for two weeks now, specifically with guest I/O disk performance. The system: -Supermicro 1018d-73mtf (X10SL7-F motherboard) -16GB ECC/UB -Intel ...
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How do you set up RAID1 with both disks bootable on Debian/Ubuntu?

In Debian 6, new installation, what is the recommended way of setting up a software RAID1 array so that the system is bootable from both disks? I have heard that people that don't know what they are ...
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Removing a device in “removed” state from Linux software RAID array

My workstation has two disks(/dev/sd[ab]), both with similar partitioning. /dev/sdb failed, and cat /proc/mdstat stopped showing the second sdb partition. I ran mdadm --fail and mdadm --remove for ...
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1answer
705 views

mdadm kernel log messages explained

Welcome. I try to recover from linux software raid failure. I am in a process of recreating the superblocks based on a syslog from the system when it was healthy. The log speaks about 2 md devices, ...
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1answer
2k views

Linux raid controller (LVM/MDADM)

Today I'm in a very bad place. A production raid array went down. The controller failed. After unmounting the file systems and killing all processes, I changed the hardware controller. On restarting ...
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1answer
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Unresponsive mdadm

I have a raid 5 mdadm raid array set up with 6 drives and a hot spare on an Ubuntu 11 server. There are a couple samba shares on the drive, and until today, they were working well. A couple hours ago ...
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Odd mdadm output: --examine shows array state failed, --detail shows everything clean

The setup: 8 disks in a mdadm-managed RAID5 array (/dev/md0, made from /dev/sdc through /dev/sdj). One disk (/dev/sdh) is showing SMART errors (increasing pending sector count) so I'm looking to ...
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ext3 format options

I'm creating a ext3 filesystem on top of a software raid5 (md) and I'm wondering what are the best parameters when creating the filesystem (with mkfs.ext3) and while mounting. RAID5 chunk size is ...