RAID - Redundant Array of Independent Disks. A Storage technology to provide redundancy and performance, to reduce I/O bottlenecks involved in using multiple disks for large storage.

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How to set up disk mirroring (RAID-1)

I have a computer with two WD 1TB drives and I want to configure disk mirroring on it. I tried setting up RAID during the installation by creating RAID partitions but that does not work for me. Is ...
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RAIDing with LVM vs MDRAID - pros and cons?

In his answer to the question "mixed raid types", HBruijn suggests using LVM to implement RAID vs the more standard MDRAID. After a little investigation, it seems LVM also supports RAID ...
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recovery data from RAID and disk failure (Linux)

Some background A friend of mine was using in his office a NAS Buffalo-LS-WVL with two disks of 1TB each. It seems that the two disks were mounted as raid 1, but, as you will read, probably they have ...
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md raid5: translate md internal sector numbers to offsets

TL;DR summary: Translate an md sector number into offsets(s) within the /dev/mdX device, and how to investigate it with xfs_db. The sector number is from sh->sector in linux/drivers/md/raid5.c:...
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Will the system make sure that mdadm is sync-ed before completing a reboot?

This is a follow up to my crazy mdadm problem. I'm trying to figure out what might have caused sda to get out of sync in the first place. The only thing I can think of is that I had just run a bunch ...
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What steps can I use to recover a RAID 1 array with LVM and EXT3 on it?

Someone handed me a drive that used to be part of a RAID 1 (mirror) array. The drive apparently has LVM (1?) on it and EXT3 (I believe). What steps can I take to regain access to this drive? ...
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427 views

Get Position of RAID Hard Drives

I was recently tasked with creating a hard drive management system on Linux. I needed to write a program that monitored when drives came online and offline and created/removed links to the drive ...
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bit rot detection and correction with mdadm

I'm about to re-organise all my HDDs in my linux box nas and would like to use mdadm raid for data protection and its flexibility for reshaping the arrays. However, before I use mdadm for this I'd ...
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Linux: LUKS and multiple hard drives

I have a Debian Linux system (amd64) installed on a RAID-1 system encrypted device (LVM on LUKS) and will have a RAID-6 of >=4 disks where I'll put my data (LUKS and maybe LVM). I think the basic ...
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1answer
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New md array is auto-read-only and has resync=PENDING

I've created a new md array with the following command: mdadm --create /dev/md1 -l 1 -n 2 /dev/sd[ed]1 But now /proc/mdstat shows the array as "auto-read-only" with resync=PENDING: ~ # cat /proc/...
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3answers
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Partitioning EFI machine with two SSD disks in mirror

I have two SSD disks, I want to put them in a software mirror RAID. But whatever I do the OpenSuSe installation keeps telling me that due to the partitioning scheme he won't be able to install the ...
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3answers
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Avoid pause during dm-raid initialization

On my CentOS 5 workstation I get a few seconds wait after dm-raid45 has been loaded ("Initializing Driver" or something like that). This seems to be part of the initrd. After that the system boots up....
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1answer
401 views

Drive was unable to assemble into the array

I ran mdadm -A /dev/md0 /dev/sda1 /dev/sdb1 Only /dev/sdb1 was loaded into the array though. I have a few more arrays on the same two drives too. Each time the partition on sda failed. dmesg told ...
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2answers
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Raid devices are mounted with different UUID

Centos 7.1 64. This is what I have: Two raids, but not md0 and md1 [root@localhost]# cat /proc/mdstat Personalities : [raid1] md126 : active raid1 sdb2[1] sda2[0] 974711616 blocks super 1.0 [2/...
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1answer
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Grub fails to install - Debian Wheezy with mdadm RAID1 and GPT partition table

I've been trying all day to get my new Wheezy install completed but it fail to install Grub every time. I'm using x64 netinstall iso. Here is my partition table: Model: ATA ST3000DM001-1CH1 (scsi) ...
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1answer
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Prevent debian from hindering boot if a software-raid problem exists

I have a computer that I rarely have physical access to. All my access to that computer is done using SSH. On that computer, there's a software RAID5 using MDADM. This array contains data in one ...
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1answer
137 views

Why does mdadm believe my raid1 “has failed so using --add cannot work”?

TLDR: Trying to add a blank partition to a degraded RAID1 with mdadm 3.3.2 (Debian Jessie) fails, saying the (perfectly working!) array has "failed" and "--add cannot work". Is it telling me of a real ...
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2answers
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New RAID array will not auto assemble, leads to boot problems

I had just asked this question where I was unable to boot after installing a new RAID1 Array. I was able to get to the terminal, but once I sorted that out I realized that my problem isn't so much an ...
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2answers
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Linux software RAID-1 and device name

I want to set up software RAID-1 on my Ubuntu system, and found this example of an /etc/raidtab: raiddev /dev/md0 raid-level 1 nr-raid-disks 2 nr-spare-disks 0 persistent-...
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What chunks are mismatched in a Linux md array?

This is a repost of a question I asked on ServerFault and was automatically deleted for lack of activity. Let's hope it will have better luck here. After performing a "check" (by writing check to /...
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Are disks interchangeable in a mirrored RAID setup?

It is often written that disks in a mirrored RAID (like RAID 1) are an exact mirror copy one of another. So can I turn the machine off and simply swap the two harddisks cables? And if one of the two ...
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1answer
125 views

RAID mount not happening automatically

I've configured RAID array in my SUSE machine. Everything works just fine as expected. However, I need to mount the RAID array automatically when I boot my system. For this I added the mount point in /...
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1answer
371 views

mixed raid types

I am about to reinitialise my (SW) raid array. Previously the array was raid5 with 4 disks. I've removed one disk in order to install a new additional (larger) drive. What I'd ideally like to do is ...
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1answer
221 views

How do I clone a single drive onto a new RAID 1 array?

Here's a little background on the situation at hand. I have a DELL Precision T7600 at work that I'm responsible for maintaining, which just lost a hard-drive, thankfully just the /home directory was ...
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2answers
384 views

Copying linux install from non-RAID/x86 to RAID/x86-64

I'm copying an Ubuntu Server install from an x86 machine with a single hard disk to a new machine with x64 and two identical disks. Two partitions will span the new disks: One small-ish RAID1 for ...
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1answer
105 views

Where to install GRUB?

I am running Ubuntu 14.04 on a remote server. It's the only OS installed. I need to be super-cautious before rebooting the machine since KVM access to the server is quite tricky. During a GRUB update,...