A linux utility used to manage software RAID devices.

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1answer
142 views

How to identify raid1 disks

I would like to know how mdadm identifies physical disks of raid1 . I think it is managed by uuids not device file like /dev/sdc2 /dev/sdd2. But I can`t confirm such information of raid1.
9
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4answers
10k views

Does RAID1 increase performance with Linux mdadm?

I have a cheap 2-bay NAS with a 2TB HDD. To be robust against disk failure, I'm thinking of buying a second 2TB HDD and putting it in RAID1 with Linux mdadm. The file system is ext4. Will this ...
4
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2answers
2k views

Fault tolerant RAID6 / RAID10 design for home server - not performance critical

I want to balance disk space against fault tolerance. I would like fault tolerance to be able to handle multiple disk failures (as I may not be able to afford replacements disks or have the time for ...
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2answers
4k views

How does one enable --write-mostly with Linux RAID?

Unfortunately the mdadm and mdadm.conf man pages are not quite up to par. I would like to enable the --write-mostly flag for my RAID, but neither the man pages nor the internet will tell me how. I am ...
2
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4answers
6k views

How do I mount a software RAID1 (mirror) created by windows in Linux using mdadm?

I'm switching my Windows server to Ubuntu and am trying to get my software RAID1 (mirror) that I created in Windows to show up in Ubuntu. I have read that this is possible here using mdadm, but I'm ...
1
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1answer
1k views

degraded mdadm RAID5 array

My /dev/md0 array just died last night. I got this email This is an automatically generated mail message from mdadm running on A Fail event had been detected on md device /dev/md0. It ...
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2answers
297 views

Is it possible to safely get data off a hard drive thats a member of a mdadm-mounted RAID1 array via USB?

I have a RAID1 array of two drives created with mdadm. Is it possible to remove one of the drives, hook it up to a USB SATA adapter, and safely mount it, get the info off of it, and return the drive? ...
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2answers
4k views

Btrfs on top of a mdadm raid10, or btrfs raid10 on bare devices?

I have a RAID10 managed by the mdadm and I have EXT4 filesystem on top of it. However, I like BTRFS and would like to convert the EXT4 filesystem to BTRFS, but I was thinking about performance and ...
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2answers
1k views

How to remove a drive from a non-standard 2-drive RAID 5 array?

There is some information available on shape changes in RAID arrays but I'm a little nervous and would like confirmation: Problem: I have 2 500GB drive as software raid 5 (mdadm). I would like to ...
1
vote
1answer
785 views

CentOS - mdadm raid1 drive won't mount to default location

I'm running CentOS 5.5, the system, boot, swap, etc. is all on /dev/sda and I have two identical single-partition drives /dev/sdb1 /dev/sdc1 that are configured in RAID1 (using mdadm). It was working ...
12
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3answers
30k views

How-to change the name of an MD device (mdadm)

Here is the output from mdadm -Esv: ARRAY /dev/md127 level=raid0 num-devices=2 UUID=d89d9d45:9a420812:c44c77eb:7ee19756 devices=/dev/sdb8,/dev/sda8 This is a v0.90 array. The question is as ...
2
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1answer
7k views

determine chunk size of an existing raid array

What should I do to determine chuck size of existing raid arrays. I'm using software raid created by mdadm. I've been probing around for a while and can't find the right utility to that job. mdadm --...
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3answers
3k views

Is it safe to put harddisks of a md-software-raid to standby?

I have a home-fileserver with 6 desktop harddisks in a md-raid. The server isn't accessed a lot, so I think it would be good for the harddrives to go in standby-mode after some idle time (e.g. with ...
3
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2answers
341 views

What would you see if you tried to mount a single drive from a RAID 5 Array?

The title pretty much sums it up - if someone were to mount a single drive from a software RAID 5 array, what would they see? Would it point to being part of a RAID array, appear as encrypted data, or ...
6
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6answers
12k views

Adding drives to a RAID 10 Array

How would I grow a RAID10 array using mdadm? Obviously I would need to add 2 drives at a time, or would it have to be 4 drives? I have a feeling its just a bad idea. Or would be just wiser to just ...
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2answers
912 views

Recover Linux software RAID5 array after server upgrade

I recently upgraded a server from Fedora 6 to Fedora 14. In addition to the main hard drive where the OS is installed, I have 3 1TB hard drives configured for RAID5 (via software). After the upgrade, ...
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7answers
67k views

How can I make mdadm auto-assemble RAID after each boot?

I successfully created a RAID (mirroring) by utilizing mdadm. However, I must run the following commands after each boot: mdadm --stop --scan // to stop /dev/md127 - I don't know where the number 127 ...
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0answers
306 views

Lots of fun problems with RAID and SATA controllers

I bought a used 3ware raid card off of ebay a few months back and set up four 1TB caviar blacks in RAID5. The hardware raid could only manage about 5MB/s writing without write caching, and I don't ...
2
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2answers
340 views

Recover from failed recovery of software RAID5 failure

I have the pleasure ;-) to have been handed the task to try to get data off a server that had a RAID5 array problem and a failed attempt to recover it. Background: the computer in question is some ...
0
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1answer
1k views

mdadm raid-1 after restarting usb devices not accessible anymore

Is my mdadm software raid in danger of data loss??? My both two new built raid-1 on external usb disks behave strangely. Both were fine and rebuilt and cat /proc/mdstat showed Every 10,0s: cat /...
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1answer
1k views

raid-1: increase rebuild speed on current rebuild

I see my raid-1 array rebuilding (first time after adding 2nd partition) and want to increase speed SO I set echo 100000 > /proc/sys/dev/raid/speed_limit_min echo 400000 > /proc/sys/dev/raid/...
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3answers
167 views

Can RAID5 drives be defective while passing self-tests?

I have a 4-drive RAID5 in Ubuntu 10.10 with mdadm. One of the disks seems to be problematic. It dropped from the RAID, and I re-added it and it was fine for a while, but now when I re-add it I get a ...
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3answers
5k views

Raid1 with active and spare partition

I am having the following problem with a RAID1 software raid partition on my Ubuntu system (10.04 LTS, 2.6.32-24-server in case it matters). One of my disks (sdb5) reported I/O errors and was ...
2
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1answer
2k views

Auto-rebuild RAID6 with MDADM

I have an openSUSE 11.3 Linux computer with 5 disks of 1TB (WD enterprise disks) in it. With mdadm I configured a RAID6 device. Now, after a lot of thorough testing, I've noticed that when the ...
2
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1answer
295 views

convert full-disk RAID5 array to partition-based array?

I have a RAID 5 array, md0, with three full-disk (non-partitioned) members, sdb, sdc, and sdd. My computer will hang during the AHCI BIOS if AHCI is enabled instead of IDE, if these drives are plugged ...
6
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4answers
8k views

mdadm volume works, but won't assemble/mount on startup?

I have an mdadm/lvm2 volume with 4 HDs that I created in Ubuntu 10.04. I just upgraded the computer to Ubuntu 10.10. I redid the mdadm commands to get volume up and running, did mdadm --detail --scan ...
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3answers
471 views

Fluctuating transfer speeds with md RAID5/vsftpd

I have an Ubuntu 8.04.4 server with an md RAID5 consisting of 9 drives. While transferring a large amount of data to it (through vsftpd) I noticed very bad transfer speed fluctuation. For example ...
0
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1answer
1k views

mdadm device missing

after a reboot my /dev/md0 device was missing. This is a RAID-1 array from two partitions of two harddrives. On each of the harddrives is another partition, which together belong to dev/md1. However, ...
2
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1answer
2k views

how can fsck to recover from hardware failure?

I have a RAID 5 array using mdadm and ext4 as its filesystem. We got a strong power surge and one of the drive faulted, while another one got a bit flakky, aka "click of death". I replaced the disks ...
1
vote
1answer
430 views

Paritions “appear” in my raid 1 array after reboot, and the partitions in the array have changed names

I am moving my Ubuntu install to lvm over raid 1. I created the arrays with only 1 disk initially, planning to add the second disk later. I got the files moved and the system booted up succesfully on ...
5
votes
1answer
4k views

Possible mdadm RAID states?

I'm writing a monitoring plugin for a home server RAID, mdadm on Ubuntu 10.4. Using sudo mdadm --detail /dev/md0 I get output like this: /dev/md0: Version : 00.90 Creation Time : Thu Dec ...
2
votes
1answer
203 views

Gentoo Linux -> Ubuntu: Can I Preserve My LVM/RAID Devices, Or Do I Need To Reformat?

I've got a Gentoo box that I'm interested in switching over to an Ubuntu box. I currently have the partitions laid out using a mixture of RAID (mdadm) and LVM2, as specified in this document [1]. ...
2
votes
3answers
1k views

RAID-1 and regular drive removal (using RAID-1 as a backup measure)

Is using mdadm's RAID-1 of 2 partitions (one on laptop's internal HDD, one on external HDD) a good idea. I want the system to work as RAID-1 if both drives are present, work as regular volume (...
23
votes
8answers
121k views

How to get an inactive RAID device working again?

After booting, my RAID1 device (/dev/md_d0 *) sometimes goes in some funny state and I cannot mount it. * Originally I created /dev/md0 but it has somehow changed itself into /dev/md_d0. # mount /...
6
votes
3answers
19k views

Creating a RAID1 partition with mdadm on Ubuntu

I'm trying to set up a RAID1 partition on my Ubuntu 9.10 workstation. On this dual-boot system, Ubuntu is running from a separate drive (/dev/sdc - an SSD that is quite small, which is why I need ...
2
votes
2answers
668 views

Linux drive permissions for disk used by two systems

I've got a large mdadm-based RAID5 array that I've been using with an Ubuntu 8.04 system. I'm setting up a new 9.10 (alpha 6) system on the same hardware. mdadm does a great job automagically ...