A linux utility used to manage software RAID devices.

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How to safely replace a not-yet-failed disk in a Linux RAID5 array?

I have a software RAID5 array (Linux md) on 4 disks. I would like to replace one of the disks with a new one, without putting the array in a degraded state, and if possible, online. How would that ...
6
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2answers
1k 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 ...
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vote
1answer
143 views

Unable to check a mdadm RAID1 array, says the file system's read only?

I recently migrated a RAID1 from a CentOS 5 system to a CentOS 6 system and ever since when I attempt to perform a check I get the following: $ echo 'check' > /sys/block/md127/md/sync_action ...
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3answers
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Difference between UUID from blkid and mdadm?

Can someone explain the difference between the UUID's reported by blkid and mdadm? On one of our CentOS systems, for example: [root@server ~]# blkid | grep /dev/md1 /dev/md1: ...
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4answers
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Monitor disk health using smartd (in smartmontools) on a high availability software RAID 1 server

I have a server with three identical SATA/600 3TB drives: /dev/sda, /dev/sdb, /dev/sdc. The drives are partitioned, using GPT with three partitions each: 1 MB: Reserved partition for boot loader 1 ...
7
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1answer
13k views

mdadm raid1 and what chunksize (or blocksize) on 4k drives?

I want to use two 3 TB drives in a mdadm raid1 setup (using Debian Sequeeze). The drives use 4k hardware sectors instead of the traditional 512 byte ones. I am a bit confused because on the one hand ...
3
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1answer
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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 ...
2
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1answer
382 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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What does mdadm's “spare” number mean?

I created a mdadm-based RAID 5 from six hard drives using the following command: # mdadm --create /dev/md0 --level=5 --raid-devices=5 \ /dev/sdb1 /dev/sdc1 /dev/sdd1 /dev/sde1 /dev/sdf1 \ ...
2
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2answers
203 views

raid5 exchange 1 of 3 harddrives [duplicate]

I want to exchange a Harddrive which is in a pre-failing state, (some reallocated sectors) which is used in a raid5 array with 3 disks (software raid with mdadm). Is it possible to set a new ...
2
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1answer
1k views

convert /dev/md0 to /dev/sda1

I used a Software-RAID I and want to access the data without RAID now. After mdadm --fail /dev/md0 /dev/sda1 mdadm --remove /dev/md0 /dev/sda1 I tried mount -t ext4 /dev/sda1 /mnt but dmesg ...
1
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1answer
138 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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0answers
3k views

Linux md RAID: /dev/md0 vs. /dev/md/0

On newer systems /usr/share/mdadm/mkconf (the script that is used to generate /etc/mdadm/mdadm.conf) tends to use the device name /dev/md/0 instead of /dev/md0: new-system ~ # /usr/share/mdadm/mkconf ...
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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 ...