A linux utility used to manage software RAID devices.

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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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2k views

How to boot with RAID 1 in GRUB rescue?

Basic working system details: I used the Ubuntu 12.04 server CD to install a server. I have 2 disks. I made a raid 1 array just like in ubuntu server guide : ...
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2answers
170 views

Production Disk Failure - Lucky it's sunday and out of hours (mdadm raid 5)

I have a production raid array that has hit problems. Luckily when I configured it I assigned a hot spare. Here is what the status looks like now: mdadm --detail /dev/md2 /dev/md2: Version : ...
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202 views

Optimized raid 0 configuration for Amazon EC2 hi1.4xlarge

How do I know what is the best configuration for RAID 0 (mdadm create options) between the to ephemeral drives?
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2answers
762 views

Determining the software RAID configuration on an Ubuntu server

I have an Ubuntu box which was installed by an admin who is not with me now. I have no information on how he configured the RAID and neither no experience on setting up a software RAID on Linux ...
4
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1answer
366 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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2answers
3k views

how to know what is disk uuid for md raid1 and hdparm?

ive got md0 (raid 1) array and want to make write cache off on them during system boot (ubuntu 12.04 server). md0: /dev/sda /dev/sdc blkid: /dev/sda: UUID="3e502de5-696d-f4b4-470e-XXX" ...
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1answer
492 views

Rebuild doesn't finish after raid1 disk replacement

In one of our servers one of the disk failed, no worries it happens all the time, we replaced the bad disk following the usual procedure but then ... 'the horror', after adding a new disk one of the ...
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2answers
346 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 ...
2
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1answer
268 views

LVM incorrectly reported missing after power failure

We have had a major power failure in the data-center. We are using a set of servers for our storage needs. The main server has several pairs of disks mirrored with mdadm. The resulting /dev/mdX are ...
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1answer
417 views

How do I keep mdadm from renaming my RAID array upon reboot?

So I have a system (a large instance running ubuntu-11.10 on Amazon EC2) where I've done something like mdadm --create bigdata --level 0 --raid-devices=2 /dev/xvdb /dev/xvdc I get a RAID device ...
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1answer
590 views

What was the default chunk size in previous versions of mdadm? Is there a way to set data/super offset? Trying to recreate a raid 5 md with all spares

I have a 6 device raid 5 array which had 1 disk go bad and then due to a power outage, the machine shutdown and when it started all the disks were showing up as spares with the following mdadm -E ...
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2answers
812 views

How to move Mdadm RAID drive (EBS based) to different AWS Instance

We have a media-rich web application that is hosted on AWS. We have several Web Servers and we have an NFS server. On the NFS server (Linux server) we have several EBS volumes that are mounted and ...
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2answers
1k views

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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2answers
87 views

Raid array on partition bleeds through to block device

EDIT: It appears that this might be an inherent issue with the .9 superblock version. Figures that I would only be able to find these links after I posted here. ...
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2answers
1k views

Linux mdadm software RAID 6 - does it support bit corruption recovery?

Wikipedia says "RAID 2 is the only standard RAID level, other than some implementations of RAID 6, which can automatically recover accurate data from single-bit corruption in data." Does anyone know ...
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2answers
1k views

mdadm raid5 too slow when writing

I have set up a RAID5 array using 4 disk partition. All disks are 2TB. When the RAID5 array was initially syncing it was too slow. So I did a echo 32768 > /sys/block/md2/md/stripe_cache_size and ...
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2answers
711 views

strange mdadm behavior - on failing to create, md127 appears with “Device or resource busy” on freshly created partially zeroed partition

Problem: # ls /dev/md* /dev/md0 /dev/md1 # dd if=/dev/zero of=/dev/sdb3 bs=1M count=1 # dd if=/dev/zero of=/dev/sdd3 bs=1M count=1 # mdadm --zero-superblock /dev/sdb3 # mdadm --zero-superblock ...
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1answer
8k views

Ubuntu server, gpt partition table, mdadm, grub boot fail

Basic working system details: I used the Ubuntu 12.04 server CD to install a server. I have 4 disks. On all disks I did the following, similar to this howto : created a 2GB swap partition created ...
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0answers
989 views

Can't mount logical volume, RAID/MD/LVM problems

I have a file server with 48 2TB HDDs split across 2x 3ware 9650SE-24M8 RAID cards. Both cards have 24 drives in RAID 1+0. MD softraid is setup in raid 0 with the two RAID 1+0s making RAID 100. LVM2 ...
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1answer
786 views

MDADM not able to connect to EBS drives on Ubuntu 11.10

I have been using a raid.sh script [1] for over a year now and has never gave me trouble. I recently started moving from Ubuntu 10.04 machines on AWS to Ubuntu 11.10. I updated the raid.sh script from ...
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1answer
943 views

mdadm warning after apt-get upgrade - can't boot RAID

I'm running Ubuntu 12.04 precise. A recent apt-get upgrade ended successfully, but printed the following warning at the end: update-initramfs: Generating /boot/initrd.img-3.2.0-21-generic W: mdadm: ...
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173 views

Does linux software raid10 perform any data verification on each write?

I wand to find out is there any benefit in safety of storage data between manual sync(using cron & rsync) of two RAID0 volumes and RAID10 volume using Linux software raid. Does RAID10 preform any ...
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3answers
943 views

Can I convert a raid10 array to raid0?

I have created a raid10 array using mdadm. Metadata version is 1.2. I want to convert this to a raid0 array, is it possible? P.S. I am having terabytes of data, I want to avoid copying the data over. ...
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1answer
569 views

How to force mdadm to use udev device names rather than /dev/sdX

The question is mostly in the title already. mdadm and /proc/mdstat insist on listing md members by their "traditional" /dev/sdX names. What I want is for them to use the newer udev device names ...
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1answer
3k views

Build and migrated to software raid (mdadm) on GPT disk, now can't assemble array

mdadm, gpt issues, unrecognized partitions. Simplified question: How do I get mdadm to recognize GPT partitions? I have been attempting to convert/copy my Ubuntu 11.10 OS from a single drive to ...
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322 views

MD Raid can't be assembled

I was running a Raid5 with 3 disks at on my homeserver. But had some problems with the back-plane for the disks. The disks weren't detected reliable. So I replaced the back plane and the disks are now ...
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2answers
2k views

Cant boot newly created mdadm software raid in Debian linux squeeze

Hello I have very strange problem creating swraid on Debian Squeeze Linux. I started creating RAID1 from existing standard instalation of Debian on single drive. So I bought new drive and started ...
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2answers
536 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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347 views

Relabeling of filesystems (SELinux) fails

After compiling the policy modules and re-compiling my core packages (Gentoo 32bit) I wanted to relabel the filesystems (via rlpkg -a -r) and packages but I get these error messages: Relabeling ...
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2answers
892 views

Move an existing RAID 5 array from Ubuntu to Gentoo

I have a 64-bit Ubuntu machine with a 4-disk RAID 5 using software raid (md). I've been able to boot an Ubuntu LiveCD and recognize the array with a simple mdadm -A /dev/md0. It was easy to mount ...
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836 views

mdadm raid1, [1/2] disks failed, safe to reboot?

I am seeing the following under /proc/mdstat Personalities : [raid1] md1 : active raid1 sda2[0](F) sdb2[1] 976554876 blocks super 1.1 [2/1] [_U] bitmap: 4/8 pages [16KB], 65536KB chunk md0 : active ...
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427 views

How do I create a RAID10 array using EBS on Amazon?

Basing this question on information I got in Why does df shows only half the size of a RAID10 array?, how should I create a RAID10 array using EBS volumes on Amazon, in a way that will not be ...
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269 views

After upgrade to SLES11 SP1 - LVM on top of software RAID5 not working anymore

On a system where I have been running OpenSuSE11.1 for some time I performed a fresh installation of SLES11 SP1. The system used a software RAID5 system on top of which an LVM was setup with a single ...
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4answers
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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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1answer
598 views

mdadm: hot remove failed for…

My RAID1 is degraded and I need to replace /dev/sdb. However, I could mark /dev/sdb5 (in /dev/md1) as failed and removed it, but I can't do the same with /dev/sdb1 (/dev/md0 which is mounted on /): ...
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1answer
208 views

get mkfs.xfs options from existing xfs filesystem

I set up a new server last week, did some testing with different mkfs.xfs options on mdadm raid5, i finally found some statisfying mkfs options. Now i am about to set up a new server having exactly ...
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0answers
144 views

mdadm LBA mapping

I am trying to write a script similar to mdtrim (https://github.com/Cyberax/mdtrim) for a raid 0 software raid through mdadm. The mdtrim is for raid 1 only at the moment, and it works by writing a ...
4
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1answer
437 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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1answer
1k views

How to disable mdadm when running hardware RAID

My server Dell R210 runs a Debian squeeze with hardware RAID1 (H200) preconfigured. But I notice that there is mdadm running. Sometimes in backup, or in OS upgrade (to Debian 6.0.4), I have messages ...
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500 views

Rebuilt md raid 6 array now showing xfs errors. How bad is it?

We had a storage server with performance starting to be poor. When I installed Linux's smartutils, it found Device: /dev/sdm, 2 Offline uncorrectable sectors Since this was a rather large raid6 ...
5
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1answer
871 views

Use cases for “mdadm --create” vs. “mdadm --build”?

From the mdadm man page, --build section: This usage is similar to --create. The difference is that it creates a legacy array without a superblock. ^^ So no superblock with --build. 10-4. ...
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580 views

Cryptsetup device /dev/md0 is not a valid luks device

After reinstallation of my OS, I decide to manually assemble a RAID6 array. # mdadm --assemble --auto=yes --scan=auto /dev/md0 I don't exactly remember a message but programmdadm return a resizing ...
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4answers
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Recover RAID 5 data after created new array instead of re-using

Folks please help - I am a newb with a major headache at hand (perfect storm situation). I have a 3 1tb hdd on my ubuntu 11.04 configured as software raid 5. The data had been copied weekly onto ...
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3answers
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Creating a partitioned raid1 array for booting a debian squeeze system

I'd like to have the following raid1 (mirror) setup: /dev/md0 consists of /dev/sda and /dev/sdb I created this raid1 device using mdadm --create --verbose /dev/md0 --auto=yes --level=1 ...
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1answer
708 views

how to migrate lvm mirrorlog from physical partition

Output from: sudo lvs --all -o +devices root hp03 mwa-ao 18.62g root_mlog 100.00 root_mimage_0(0),root_mimage_1(0) ...
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2answers
949 views

Linux: very slow mdadm resync on raid 1

I'm trying to rsync a RAID 1 on a system with absolutely nothing running ( i've moved all services to another server ). So it's just me via ssh. For some reason, it's very slow: cat /proc/mdstat ...
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2answers
865 views

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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191 views

Recovering linux software RAID array without removing it's items

I have linux software raid (RAID10), md2 : active raid10 sda6[4](F) sdd5[3] sdc5[2] sdb6[1] 390620160 blocks 64K chunks 2 near-copies [4/3] [_UUU] which has degraded state. Can i start recovery ...
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1answer
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Ubuntu EC2 Raid0 Ephemeral — SSH connection after reboot

First, I launch a fresh large instance using the Elestic AMI ami-c162a9a8. Initially, I run: df -h /dev/xvda1 9.9G 814M 8.6G 9% / udev 3.7G 4.0K 3.7G 1% /dev ...