Questions tagged [mdadm]

A linux utility used to manage software RAID devices.

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flashcache with mdadm and LVM

I am having trouble setting up flashcache on a system with LVM and mdadm, I suspect I am either just missing an obvious step or getting some mapping wrong and hoped someone could point me in the right direction? system info: CentOS 6.4 64 bit mdadm…
Backtogeek
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Path of md device wrong after reboot

I have to set up a software raid (level1) on a Ubuntu server 12.04. It should serve files in the network via Samba. The server has the following disks: 250gb Sata hdd (Ubuntu is installed on that drive) 2 TB Sata hdd (first disk in raid array,…
flammi88
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syncing mdadm event count

I had a disk die in my level 5 RAID and before I could replace it, my RAID crapped out while I was copying some data onto it. Reading the RAID kernel wiki on RAID recovery I've tried forcing an assemble with no success: # mdadm --assemble --force…
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How do I check if smartd and mdadm are running correctly?

I have a raid system on debian: Disk /dev/sda: 320.1 GB,... Device Boot Start End Blocks Id System /dev/sda1 * 1 2432 19535008+ fd Linux raid autodetect /dev/sda2 2433 2918 …
rubo77
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Remake SW RAID1 from a new HDD and an old HDD with bad blocks

I have a SW RAID1 and I just replaced /dev/sda with a new HDD as the old one failed. Now, upon trying to recreate the RAID array I discovered that the "good" HDD (/dev/sdb) has bad blocks with prevent mdadm from resyncing the array. While I…
Alex Flo
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Recover mdadm RAID 10 array: listing all as spares

I'm a bad person and haven't backed up my RAID elsewhere. I now have a RAID10 array that won't assemble, and I'm hopeful I can save it. Here's the details: I have five hard drives set up as RAID10 (4+1 Spare). For unknown reasons, two failed and…
Eddie Parker
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mdadm reassemble from spare disk crashed during resync

The server crashed while raid-1 /dev/md2 with /dev/sda3 + /dev/sdb3 was resyncing from /dev/sdb3 to /dev/sda3. sadly, /dev/sdb was lost completely due to a hardware fault. I'm now left with only /dev/sda3 which is part of /dev/md2 but not…
mdbrk
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Are ext4 RAID5 tuning options useful under LVM?

I'm setting up a system with a system with a mdadm RAID5 which is the sole PV for a VG which hosts 4 LVs. When I make the filesystem, would the mkfs.ext4 -E option be useful? Or is its effect not possible to know because of LVM shenanigans? -E…
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Why mdadm --examine --scan gives two same ARRAYs?

The following confuses me: [root@mrak ~]# mdadm --examine --scan ARRAY /dev/md/0 metadata=1.2 UUID=d3f800db:26de8691:dc0caf45:0f75028b name=mrak.dex.internal:0 ARRAY /dev/md/0 metadata=1.2 UUID=1870fd84:2234e3d4:580f7634:b0b621e7…
DejanLekic
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mdadm did not notice a failed disk in raid0

I have a server with mdadm raid0: # mdadm --version mdadm - v3.1.4 - 31st August 2010 # uname -a Linux orkan 2.6.32-5-amd64 #1 SMP Sun Sep 23 10:07:46 UTC 2012 x86_64 GNU/Linux One of the disk has failed: # grep sdf /var/log/kern.log | head Jan 30…
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raid 5 mdadm drive dropped whilst growing

I have a 4x 2tb raid 5 mdadm array which I had begun to grow onto a 5th disk. ~# mdadm --add /dev/md1 /dev/sdb ~# mdadm --grow /dev/md1 --raid-devices=5 midway through the grow I recieved this in an email; A Fail event had been detected on md…
Thermionix
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mdadm stalls rebuilding a RAID5 array at 99.9%

I recently installed three new disks in my QNAP TS-412 NAS. These three new disks should be combined with the already present disk into a 4 disk RAID5 array, so I started the migration process. After multiple tries (each taking about 24 hours) the…
Remco Overdijk
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mdadm rebooted, array missing? can't assemble?

Not sure what is going on with my Array. I rebooted ubuntu 12.04.1 and got a error on startup that fstab couldn't mount the filesystem UUID I have for my mdadm array. After running a few commands a I found on google for mdadm, I am thoroughly…
Jim
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reliably and automatically determine connection path of physical position of HDD from /dev/sdX device file

This is kind of a FAQ, but all the answers I found so far are not suited for full automation, which is what I need. So here it goes again. In Linux: Is there a reliable way to resolve the udev device name of a HDD (e.g. "/dev/sdg") into it's data…
Jost
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Is it reasonable to make a RAID-1 array with a ram disk and a physical disk to maximize read performance and protect data?

In one of the answers on SO (I forgot which one) I've seen a suggestion to make a RAID-1 array composed of a RAM disk and a physical partition. By adding the physical partition with --write-mostly and enabling --write-behind the system should read…
Petr
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