A linux utility used to manage software RAID devices.

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1answer
132 views

mdadm raid10 or nfs performance issues?

I have a fresh mdadm RAID10 device which is healthy, built from 4 x 7200rpm SATA 3 drives: # cat /proc/mdstat Personalities : [raid10] [raid1] md2 : active raid10 sdc3[5] sda3[4] sdb3[1] sdd3[3] ...
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3answers
2k views

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 ...
0
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1answer
187 views

mdadm Build legacy array with 512-byte chunk

I'm attempting to build an array using mdadm. The array has 512-byte (not kibibyte) sized stripes. Because mdadm accepts arguments to chunk in kibibytes, not in bytes, I have been unable to build ...
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2answers
5k views

mdadm rebooted, array missing? can't assemble?

Not sure what is going on with my Array. I rebooted ubuntu 12.04.1 and got a error on startup that fstab couldn't mount the filesystem UUID I have for my mdadm array. After running a few commands a I ...
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2answers
58 views

Should I partition a RAID or just create a file system on it? [duplicate]

Given a RAID 6 created from 6 drives /dev/md0 which should be used fully for data (no booting from it, root and swap are on a different drive), should I create one partition on that device and then ...
2
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1answer
127 views

Unable to mount '/dev/sda'

My server has two 2 TB hard disk drives in soft RAID 1. I can't mount /dev/sda. Output of parted -l root@rescue:~# parted -l Model: ATA HGST HUS724020AL (scsi) Disk /dev/sda: 2000GB Sector size ...
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1answer
733 views

How to get notified of mdadm RAID problems?

I am running Ubuntu 12.04 LTS. Yesterday I found a message in my mailbox saying that my server was shut down. I proceeded to reboot the system, but it didn't come up after many minutes, and I didn't ...
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1answer
743 views

RAID Recovery on a QNAP TS-869U-RP

I've had my trusty QNAP NAS (T869-RU) fail on me over night with (apparently) two of the eight disks in the RAID5 MDADM array from /proc/mdstat: [/etc] # cat /proc/mdstat Personalities : [linear] ...
3
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2answers
785 views

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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2answers
902 views

Is it safe to interrupt a mdadm --grow operation?

I recently changed the disks in my RAID5 from 3x2TB to 3x3TB. I also wanted to change the chunk size from default 512k to 128k. I have added all new devices to the array and I run: mdadm /dev/md1 ...
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2answers
314 views

Ubuntu 12.04 Server Software RAID1 - Faulty Spare - Smart Output Passed - Confused

I think I'm having an issue with one of the hard drives on my array and I'm just trying to troubleshoot what's happening. Its saying Faulty Spare and then after reboot it just says removed: ...
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1answer
33 views

mdadm reports faulty disk, but smart doesn't find problems

I've got a 9 disk raid 5 array. Today i got a mail from my server: This is an automatically generated mail message from mdadm running on Eldorado A Fail event had been detected on md device ...
2
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1answer
33 views

MD RAID sector repair

This article states that RAID controllers are smart about unrecoverable read errors, and try to rewrite such sectors with the redundancy of the component drives. If the sector is bad, the disk's ...
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0answers
22 views

mdadm: All RAID disks look good, but can't access devices

Now, granted, issues with RAID rarely come up (at least with the one that I have to deal with in my life), so I'm not the most experienced person in the world. However, I'm not seeing any issues with ...
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2answers
40 views

soft raid6 recover second disk fault

I had a disk failure in a hosted system and had the failed drive replaced. During recovery, a disk error on a different drive occurred. when the original error occurred: md2 : active raid6 ...
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2answers
136 views

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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0answers
197 views

Ubuntu 14.04 mdadm issues on boot

I have a 14.04 Ubuntu machine which has: 2 x SSD in RAID 1 (md0) 3 x Sata HDD in RAID 5 (md1) The machine is set to boot from the md0 device. This machine has been running fine for a month or so, ...
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1answer
28 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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2answers
113 views

Reassemble RAID 1 array from old system

I recently upgraded my OS from RHEL 5 to 6. To do so, I installed the new OS on new disks, and I want to mount the old disks. The old disks are listed as /dev/sdc and sdd in the new system, they were ...
6
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1answer
4k views

mdadm and 4k sectors (advanced format)

There are numerous questions on Serverfault about aligning 4k sectors disks, but one thing is not really clear to me yet. I successfully aligned my RAID1+LVM. One of the things I did was use mdadm ...
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3answers
150 views

mdadm - Remove disk from RAID0

So, I'd like to know, is is possible to do the following with mdadm: I start with RAID0 configuration on 2 disks: sda and sdb. I would like to add one more disk to array, sdc and move all data from ...
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1answer
23 views

Force server to use all resources for resync

I need to resync my RAID and noticed that it isn't a big consumer. I have booted my system with the Rescue CD and started the resync. Looking at top it seems that the processes doesn't take much ...
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3answers
10k views

How do I rename an mdadm raid array?

I have assembled a new raid array to replace an old one. However, this new array got assigned an automatic name of /dev/md127 and I want to rename it to /dev/md3, so that I don't have to change ...
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1answer
27 views

mdadm array is active but is not listed

I am running Ubuntu Server 12.04. I did apt-get upgrade and received a warning from mdadm. update-initramfs: Generating /boot/initrd.img-3.11.0-24-generic W: mdadm: the array /dev/md3 with UUID ...
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1answer
91 views

Reconstructing the disk order in RAID 6 with 7 disks

a little background to this question first: I am running a RAID-6 within a QNAP TS869L external RAID/NAS system. I started with 5 disks of 3 TB each back in the day, and later added another 2 disks of ...
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1answer
73 views

How to display/define Mirror/Stripping pairs with mdadm

I want to make a standard linux software Raid10 over 4 HDD. The server has 4HDDs, 2 pairs from different vendors in order to avoid batch problems. I want to have the mirror over two different ...
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1answer
32 views

Raid1+0: create stripe over two /dev/mdx on partition or not?

Given that I haven't found a way to define how a Raid10 is created with mdadm, i went the Raid1+0 solution. How to display/define Mirror/Stripping pairs with mdadm mdadm --create /dev/md0 --level=1 ...
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1answer
37 views

Use old raid drive as boot device without data loss

There were two disks in sw-raid. There were /dev/md1 as swap, /dev/md2 as boot and a /dev/md3 with ext4. The sw-raid was disabled by stopping and removing mdadm and then zeroing the superblock on ...
5
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1answer
676 views

Linux; What is stripe_cache_size and what does it do?

I am currently building a software RAID under Linux using mdadm utility and I've read a few articles that describe how to increase the stripe_cache_size value for that RAID and how to calculate an ...
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1answer
64 views

S/W RAID6 and 4k sector format — slow resync

I'm looking for reason why Linux software RAID-6 re-sync is much slower than I expected. I have used 6 WDC WD40EFRX HDDs (with 4k physical sectors) to create RAID-6 array. $ sudo mdadm -v -C ...
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58 views

Upgrade Raid 1 to Raid 0+1 and bootloader issue

I am trying to convert my current RAID 1 to RAID0+1 and facing issue in installing bootloader - please have a look what i am doing. My current configuration is RAID1(2*10GB): [root@localhost ~]# ...
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1answer
62 views

Redundancy: LVM+mdadm or LVM internal RAID

The task is to create LVM storage for virtual machine images. So LVM will be used in any case. There are two ways LVM providing redundancy: block mirroring lvcreate -m 1 --mirrorlog mirrored -n ...
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1answer
1k views

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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1answer
52 views

EC2 save mdadm RAID setup in an AMI [closed]

On EC2, most of the larger current generation instances have multiple SSD devices. To take advantage of the combined size of these for applications like nosql databases that store large amounts of ...
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1answer
78 views

System wont boot from degraded RAID6

I have a Debian Wheezy with 3 Partitions as RAID6. MD0 is for Root and OS, MD1 is for SWAP and MD2 for Files. While copy files to MD2 the system reports kernel panic and halts. I have had shutdown on ...
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2answers
468 views

Risky to have RAID5 with 3x3TB drives? What alternatives should I be considering?

A drive dropped out of my raid 5 array yesterday. It looks like the reason was due to a bad controller so I switched it out and attempted to re-add the drive but mdadm claimed it couldn't do it. So I ...
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1answer
179 views

Is it safe to snapshot an mdadm RAID with only xfs_freeze?

Is mdadm guaranteed (and trusted via experience) to be safe for taking snapshots with only an xfs_freeze? I have encountered vague warnings about mdadm still working in the background, thus making ...
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1answer
54 views

How to add partition table to existing EXT4 filesystem

I have software RAID6 on 8x3TB disks (18TB), there is filesystem od device /dev/md1, but EXT4 can`t be bigger than 16TB so there is 2TB of free space. I would like to use this space. My first idea was ...
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32 views

Did mdadm --create destroy my data?

I think I messed up pretty bad. On my old system, I had 2 identical drive that were assembled with mdadm as a MD RAID 10 with a "far" layout. When building my new system and migrating the two disks, ...
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1answer
111 views

CentOS System Recovery : Overwritten RAID Superblock and porting to new hardware

I have a failed system running on CentOS 6 and would like to attempt recovery of system. One problem it has is the mdadm superblock appears to have some issues, it has all sorts of inconsistent ...
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1answer
233 views

mdadm Stuck at rebuilding spare

I have the following Raid configuration, cat /proc/mdstat Personalities : [raid1] [raid6] [raid5] [raid4] md4 : active (auto-read-only) raid5 sda5[0] sdd5[4] sdc5[2] sdb5[1] 1536 blocks ...
0
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1answer
131 views

mdadm RAID-1 extremly slow on Debian Squeeze

Today I has started experiencing troubles with my php/web server. I've a lot of segfaults messages in php-fpm logs. At first I thought it was problems with versions incompatibility of may be some php ...
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131 views

Ubuntu 12.04 MD array not assembling after motherboard change [closed]

I recently upgraded my server by installing a new Xeon e3-1270v3 and Supermicro X10SAT board. Installation was simple and I reconnected my controller card, a LSI 9211-8i. When I booted the array would ...
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1answer
37 views

Files missing after RAID1 restore

I have encountered unpleasant situation. Given mdadm RAID1 of 2 HDD on server. Yesterday one of HDDs completely dies, other shows bad SMART status but was in accessible state. Mdadm showed "clean, ...
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1answer
117 views

DegradedArray event after rsync but later mdadm and smartctl do not show any issue

I have in my cron rsync active and I started to get emails after each rsync This is an automatically generated mail message from mdadm running on titan707 A DegradedArray event had been detected on ...
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0answers
217 views

Optimizing disk performance on KVM VM configuration

I have a KVM host server running Ubuntu 12.04 LTS, bare bones installation with only KVM installed. The server has an 8 Core Intel(R) Xeon(R) CPU E3-1230 V2 @ 3.30GHz CPU with 32GB of RAM and SATA ...
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0answers
16 views

mdadm - diffference between metadata version

Can anyone tell the difference between all the metadata versions for mdadm? When I try the command mdadm --examine /dev/sda1, I can't seem to find preferred superblocks on version 1.2. Is there a ...
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0answers
55 views

shrink live mdadm partition with LVM

My goal is to shrink an mdadm RAID 1 partition while the system is running. I have to disks sda and sdb, which build my two RAID partitions md0 and md1. On md1 I use LVM, md0 is the /boot partition. I ...
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101 views

Software RAID: file system becomes read-only, mdadm fails with SEGFAULT

I have software RAID1 on Ubuntu 10.10 (Linux ubuntu 2.6.35-32-generic-pae). It is dedicated server I control via SSH. Yesterday datacenter people changed one HDD which was crushed. I did not run ...
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1answer
407 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 ...