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Questions tagged [mdadm]

A linux utility used to manage software RAID devices.

844 questions
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mdadm: hot remove failed for…

My RAID1 is degraded and I need to replace /dev/sdb. However, I could mark /dev/sdb5 (in /dev/md1) as failed and removed it, but I can't do the same with /dev/sdb1 (/dev/md0 which is mounted on /): root@kes:~# mdadm /dev/md0 --fail /dev/sdb1 mdadm:…
tamasgal
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Impossible to stop raid device

I'm trying to stop a RAID disk in order to replace it by a new one, as this one is not working properly. I'm typing mdadm --stop /dev/md1, and I'm getting an error message: mdadm: fail to stop array /dev/md1: Device or resource busy I'm getting…
Alexis Dufrenoy
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Ext4 superblock corrupted after successful(?) mdadm grow and resize2fs

Some system details AMD Phenom II X6 1090T, 16GB DDR3 1600 running 11.04 natty, 2.6.38-8-server Raid in question consists of 5 SATA drives; 4 Samsung, 1 Western Digital; 500 GB each Drives are connected to a LSI SAS 9201-16i Host Bus Adapter…
lose_the_grimm
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Home-grown SAN -- topology ideas?

I'm interested in hand-rolling a SAN solution on Linux with the following technologies: iscsi mdadm raid lvm multipath xfs/gfs/??? teamed NICs Hardware-wise, I'm thinking of 2 x gigE (or better) switches with multiple gigE NICs on both the targets…
Brad
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Why does mdadm write unusably slow when mounted synchronously?

I have a 6 disk raid6 mdadm array I'd like to benchmark writes to: root@ubuntu:~# cat /proc/mdstat Personalities : [raid6] [raid5] [raid4] md0 : active raid6 sda[0] sdf[5] sde[4] sdd[3] sdc[2] sdb[1] 1953545984 blocks level 6, 64k chunk,…
chrishiestand
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mdadm: Replacing array with entirely new drives

I have a server with three 500GB drives, with most of my data in a RAID5 configuration spanning the three of them. I just purchased and installed four 1TB drives, and the intention is to move off of the old drives and onto the new ones. I have…
hellfur
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Why mdadm's RAID-1 is resyncing from scratch despite of the bitmap?

# cat /proc/mdstat Personalities : [raid1] md0 : active raid1 nbd0[3] sda10[0] 53246315 blocks super 1.2 [3/1] [U__] [>....................] recovery = 1.0% (537088/53246315) finish=203.0min speed=4326K/sec bitmap: 1/1 pages…
Vi.
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Creating backup disk image of RAID 1 array (MDADM)

We have some servers that run in very harsh environments (research vessel) that need to have high-availability. We have software RAID 1 for some measure of resiliency, along with proper data backups (tapes etc), however we would like to be able to…
Caligari
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mdcheck hangs when attempting to stop check

I have a raid5 array that has a check run on it once a month. It is configured so that the check runs for 6 hours from 01:00 and then stops. The following nights it will resume the check for another 6 hours until it has completed. The issue I have…
Paranoid
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How to recover mdadm raid6 array? mount: can't read superblock. 8/13 drives show all drives present, 5/13 drives show only 5 drives present

I rebooted my server today to find it hanging. I commented out the entry in fstab that loads /dev/md0 and the machine proceeded to boot. The raid was accessible and working prior to the reboot, I only rebooted because of system updates. The server…
Jieiku
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Why does mdadm --zero-superblock preserve file system information?

I have two hard drive partitions, which I have combined into a RAID1 using mdadm, and created an ext4 filesystem on the resulting device. When I mdadm --zero-superblock the two partitions, and re-create the RAID, then the original ext4 metadata is…
nh2
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What are RAID 1/10 mismatch_cnt > 0 causes except for swap file?

Two of four of my servers currently have mismatch_cnt about 40000 and that worries me. We are using RAID10 setup. Manual states, that However on RAID1 and RAID10 it is possible for software issues to cause a mismatch to be reported. This does not…
Vladislav Rastrusny
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mdadm marks hdd faulty even though it's in pristine health?

I have my custom NAS configured to spin down drives after 20 minutes of idle. Just now I checked /proc/mdstat and noticed a drive was marked as failed, however SMART shows the drive to be in very good health. Hence I suspect md-raid thought spin-up…
Cobra_Fast
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Buffer I/O Error on md-device - can't identify failed drive

Syncing my postgres master to the slave server resulted in write I/O errors on the slave (journalctl): Aug 18 03:09:23 db01a kernel: EXT4-fs warning (device dm-3): **ext4_end_bio:330: I/O error -5 writing to inode 86772956 (offset 905969664 size…
Toni
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How to recover raid? mount: can't read superblock

I had a raid5 array on /dev/md0 created with mdadm and it was working fine for about a year. It consisted of three HDDs of 1TB each. A few days ago there was a power failure and UPS failure. It was not the first time unfortunately. The OS is on a…
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