A linux utility used to manage software RAID devices.
Questions tagged [mdadm]
844 questions
3
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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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2 answers
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…

A state of panic
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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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2 answers
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…

OmnipotentEntity
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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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2 answers
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…

mateusz.kijowski
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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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3
votes
2 answers
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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