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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20
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3answers
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How to check mdadm raids while running?

I'm starting to get a collection of computers at home and to support them I have my "server" linux box running a raid array. Its currently mdadm raid1, going to raid5 once I have more drives (and ...
14
votes
2answers
9k views

What's the difference between mdadm state “active” and state “clean”

I have two different computers with different RAID5 arrays. When I run the command mdadm --detail /dev/md0 one drive reports "active" while the other reports "clean" for the "state" field. What ...
11
votes
2answers
3k views

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 ...
10
votes
2answers
23k views

How to mount a disk from destroyed raid system?

I have a horrible situation where I have to restore data from damaged raid system in a rescue Debian Linux. I just want to mount them all to /mnt/rescue in read only modus to be able to copy VMWare ...
9
votes
2answers
1k views

Choosing filesystem for a 16TB Raid

I'm just putting together a machine with eight 2TB disks. I will be using Raid 6 (12TB of usable capacity) on top of them, but I'm not sure whether I should make LVM on top of the RAID, or what ...
8
votes
1answer
11k views

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 ...
8
votes
1answer
3k views

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 ...
7
votes
1answer
3k views

mdadm Raid5 gives spares missing events

I succesfully builded up a raid5 array on debian testing (Wheezy). As the manpages and further tell, the array would be created as an out of sync array with just a new spare injected to be repaired. ...
7
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2answers
3k views

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 ...
7
votes
2answers
614 views

In place upgrade of a software raid 5 array

I run a software raid array for my backups, but my data has outgrown capacity. considering I have a full 2.4TB array with 5*600GB drives and also have 5*2TB drives I would like to swap in. What ...
7
votes
0answers
319 views

Couldn't fill logical volume maps [closed]

So I have a big problem here. On our server, there is an LVM raid with one volume group called raid. It contained two volumes, secured and unsecured and some unallocated space. Today I tried to remove ...
6
votes
1answer
126 views

Should I use `mdadm --create` to recover my RAID?

There's this guy that keeps telling me that we shouldn't use mdadm --create to recover our RAID arrays, that it's worse than evil, is an error. Why is that? I mean I should get my RAID working again, ...
6
votes
6answers
3k views

Pros and cons of software Parity-RAID (e.g. RAID5)

I was recently told about some problems concerning Parity-RAIDs without a non-volatile cache. More exspensive HW-controllers do have battery-powered caches to finish write-operations in case of power ...
6
votes
3answers
8k views

Using mdam --examine to write mdadm.conf

I'm trying to script the RAID setup for a (growing) number of identical servers. The advice I've seen for using mdadm suggests that once the RAID array has been created you can run mdadm --examine ...
6
votes
2answers
2k views

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 ...
5
votes
5answers
1k views

Consumer Level software RAID5 and LVM

Hi I am going to build a 6 drive consumer level RAID 5 (10TB) with Ubuntu10.10 and using EXT4 as filesystem, and OS on another drive. Question: Should you use LVM on top of the RAID5 or should just ...
5
votes
4answers
6k views

Mounting multiple devices at a single mount point on Linux

Is there a way to mount multiple hard drives to a single mount point? Let's say I run out of space on /home and decide to add an extra hard drive to the computer. How do I scale the space on a mount ...
5
votes
3answers
1k views

mdadm with overlaying lvm - remove a hard drive

This is a hypothetical question, I'm just evaluating in which way I should configure my hard drives for my home-server and for that I need to know this: Let's say I have a Raid5 configured with mdadm ...
5
votes
2answers
787 views

RAID 5 with 4 disks fails to operate with one failed disk?

I found a question about mdadm spare disks which almost answers my question, but it isn't clear to me what is happening. We have a RAID5 set up with 4 disks - and all are labeled in normal operation ...
5
votes
1answer
718 views

Alternatives to LVM

I was thinking about alternatives to combine several HDDs together. The only options I know so far are using LVM and/or RAID. The thing is, using LVM, I will most probably lose all data, if one ...
5
votes
0answers
4k views

Problem Installing UBUNTU 14.04 (AND Mint 16, which is based on UBUNTU 13.10) as dual boot on RAID 0 with Windows 8.1

Ok, I know that there is Dual-Boot Ubuntu 14.04 and Windows 7 on FakeRAID Installation error - question marks "????..." and that that post has some answers for me, but I don't know if it ...
4
votes
2answers
151 views

Where did 47gigabytes of space go?

Clean installation od Debian squeeze 6.0.6 x64 on intel atom 230, with 3 HDDs, with 3x500GB. df -h shows : datastore size used free % mounted /dev/md0 917G 909M 870G ...
4
votes
3answers
399 views

What would be a good choice for an elastic file system (for adding storage at a later date)?

I'm currently running a Debian 6.0 server with EXT3, but I'd like to move over to Arch. It's being used as a file server right now with a 1TB drive in it (of which 650GB in it is used). What I'd like ...
4
votes
2answers
276 views

RAID setups questions

I have a RAID setup questions My mobo supports hardware RAID, my question is, should I use the board's RAID system or freeNAS/Ubuntu's software RAID system? I realize performance is better with h/w, ...
4
votes
1answer
1k views

Unable to mount raid on my NAS, trying to rescue the data, how should I proceed?

A short backstory: something happened on my Synology NAS, apparently a buggy mailserver program that came with an update stopped the device from seeing the 2x3TB drives I have. After a lot of ...
4
votes
1answer
2k views

Why does btrfs allow to create a raid1 with mismatched drives?

I'm creating a btrfs using sudo mkfs.btrfs -m raid1 -d raid1 <small-disk> <large-disk> or sudo mkfs.btrfs -m raid1 -d raid1 <large-disk> <small-disk> it creates the fs with ...
4
votes
2answers
5k views

Strange error message during CentOS 6.5 installation regarding disk containing BIOS RAID metadata?

While attempting to use an old 40GB HDD to setup a kind of junky though usable Athon 1GHz system I ran into the following error during the HDD identification/partitioning phase of the installation: ...
4
votes
2answers
845 views

Is a ZFS storage array portable across operating systems & CPU Architectures?

I know that ZFS is available on variety of operating systems Solaris, Illumos, Linux, BSD etc. Suppose I have a bunch of disks that are part of ZFS raid file system that was created on Linux, could ...
4
votes
1answer
166 views

How mdadm recognizes which device is right one to sync others with

Imagine you have mdadm raid1 with 2 disks. Then you turn off the server, split the disks each one to different machine and boot both of them, so they will become slightly inconsistent Now you turn ...
4
votes
2answers
64 views

mdadm - Can't Remove Components In RADI1

I have my /boot partition in a RAID 1 array using mdadm. This array has degraded a few times in the past, and every time I remove the physical drive, add a new one, bring the array being to normal, ...
4
votes
1answer
5k views

No /etc/mdadm.conf in centos 6

I have installed centos 6 and setup a new RAID array with two disks. every thing is ok and I have partitioned the array but I don't see any /etc/mdadm.conf or /etc/mdadm/mdadm.conf files. I have ...
4
votes
2answers
980 views

Grow LVM RAID10?

RHEL LVM has supported RAID4/5/6 as of 6.3 and RAID10 as of 6.4. It's well-known that mdadm won't let you --grow raid10, my question is whether this is a limitation of LVM RAID10 too? If it is ...
4
votes
1answer
154 views

ext4 directory lists as a file

I'm working with a large (8TB) EXT4 filesystem in linux. After a power outage, the filesystem wouldn't mount. fsck is taking weeks to complete, but i ran testdisk and i'm able to see my partition ...
4
votes
1answer
201 views

Reusing older raid discs

I have a software RAID5 array (Linux md) on 4 disks; the OS is OpenSUSE 12.3. Recently I replaced a disc with a larger one (fail disc, remove it, add new disc). The capacity of the array has not yet ...
4
votes
3answers
3k views

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 ...
4
votes
0answers
145 views

automatic disconnection of RAID array

A RAID array connected to my system (Debian 7) via USB frequently disconnects itself for no apparent reason. Upon initial connection to the system, the device is detected, and the array can be ...
4
votes
1answer
2k views

RAID 10 can not be started

I have a RAID 10 array managed with mdadm which has failed . The symptom was that X has crashed and I was unable to logon from the terminal. I have restarted the computer and /dev/md1 did not start. ...
3
votes
2answers
349 views

Replace both disks in a raid 1 mirror

I have a 3 years old server with two same disks. I'm planning to replace both before they fails. Can I add two more new disks to the raid and (after it has been rebuild) eventually remove the two old ...
3
votes
2answers
222 views

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 ...
3
votes
2answers
820 views

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 ...
3
votes
1answer
4k views

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 ...
3
votes
3answers
154 views

Recovering data from a failing RAID 5 setup

I have a four disk RAID 5 array that is in the process of failing hard. One disk is completely dead and smartctl is telling me that a second disk is failing. All the data on the RAID is backed up, ...
3
votes
3answers
1k views

Is creating a sparse image using dd appropriate for backup/restore from a RAID?

I have two non-networked servers, each with 1.2TB of storage in a RAID5 config on an LSI MegaRaid 9240-8i controller. I have been trying without success to get Symantec Ghost to image one machine to ...
3
votes
1answer
56 views

understanding the “chunk size” in context of RAID

Am I correct that chunk size in context of RAID is essentially the same thing as cluster in file-system context? In other words, chunk size is the smallest unit of data which can be written to a ...
3
votes
4answers
446 views

Reassemble mdadm-raid5

A friend of mine has a mdadm-raid5 with 9 disks which does not reassemble anymore. After having a look at the syslog I found that the disk sdi was kicked from the array: Jul 6 08:43:25 nasty ...
3
votes
1answer
2k views

Can't mount RAID after upgrade

I just upgraded my box to 14.04 and on bootup I got a message, that my RAID devices can't be mounted automatically so I chose to skip it and work through it after boot time. Now booted up, A mount -a ...
3
votes
3answers
1k views

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 ...
3
votes
1answer
163 views

Recover data from raid 1 when both drives are faulty

I had a RAID 1 on my server, and apparently both of hard drives have failed at the same time. Server support did a quick check to confirm that HDDTEST-W1F21M6K ERROR Finished (Selftest, Device: ...
3
votes
1answer
160 views

RAID6 scrubbing mismatch repair?

You can initiate a scrub of a mdadm array with echo 'check' > /sys/block/mdX/md/sync_action, and if a bad sector is found, it'll rewrite it automatically (from a mirror or from parity information ...
3
votes
1answer
546 views

mdadm; previously working; after “failure”, cannot join array due to disk size

Abstract I had a functional Raid 5 array, I rebooted the box, and then mdadm couldn't re-assamble one part. Seeing that it was only one part, I thought it would be easy to just re-sync. But that ...