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Questions tagged [md]

Multiple Device driver aka Linux Software RAID

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VERY peculiar permission masks, UIDs, GIDs and file names in Linux

I've just booted to find my software RAID 5 in Ubuntu not mounting. When trying to mount it gave me an NFS error (which was confusing). I ran fsck on /dev/md0 and my screen scrolled with fixes for about an hour. It claimed to be complete, however…
SimonJGreen
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MD RAID 1 with external bitmap doesn't fully resync

I have an interesting configuration: dual boot system with a RAID 1 that needs to be visible in both Windows and Linux. The Windows install is Win 7 Enterprise, and the Linux install is Kubuntu 10.04. To get the RAID to work, I set it up using…
user64744
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Does Linux md-raid store backup metadata anywhere on the disk?

I know that with ext2/3/4 and other filesystems, copies of the superblock are stored throughout the disk in case the primary superblock is corrupted (https://ext4.wiki.kernel.org/index.php/Ext4_Disk_Layout). With md-raid (software raid), the…
Paul Brannan
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mdadm: power failure during raid1 rebuild

RAID1 array created with mdadm; array was rebuilding when there was a power failure. On coming back up, the array seems to be dead. # cat /proc/mdstat Personalities : [raid1] md0 : inactive sdb1[2](S) sda1[3](S) 15627751424 blocks super 1.2 # mdadm…
user5416
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Data scrubbing and repairing a RAID1 mirror?

In Linux, if I have a software RAID1 mirror /dev/md1 with N ≥ 1 active devices, what are the semantics of the repair command? echo "repair" >/sys/block/md1/md/sync_action Am I correct to assume that in case of 1 active device, the repair command…
jotik
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recover highly degraded raid array

I have a Linux RAID6 array (mdadm) composed of 8 disks. 2 disks failed. I replaced them, now I have 2 new empty disks. I would like to rebuild the raid but when I start a raid rebuild, the rebuild fails because a third disk is showing read errors…
exeral
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md raid1 reading from one disk only

I have two identical HDD in a linux software raid 1. I observed a mostly reading load on this raid device, with the process showing mostly iowait. iotop shows about 75% disk utilisation overall. If I look now at the disk utilisations of the physical…
michael
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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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RAID1: One RAID per Partition or Partitions on RAID device?

What is better suited for a normal Server: several partitions, which are bundled as several RAID1 devices (/dev/md0, /dev/md1, ...) without any partitions, which are not mirrored. one big /dev/md0, and partitions on this device What are the…
allo
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Linux Software RAID1 Rebuild Completes, but after reboot, its degraded again

I have been beating my head with an issue here, and I'm now turning to the internet for help. I have a system running Mandrake Linux, with the following configuration: /dev/hda - This is a IDE drive. Has some partitions on it that boot the system…
zimmy6996
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Linux Software RAID recovery

I am seeing a discrepancy between the output of mdadm --detail and mdadm --examine, and I don't understand why. This output mdadm --detail /dev/md2 /dev/md2: Version : 0.90 Creation Time : Wed Mar 14 18:20:52 2012 Raid Level :…
Zoredache
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How do I make grub install on a software-raid disk?

I am running Debian 9 with mdadm RAID 1 on it. Previously both hard-drives could boot into the OS, now only one of them can. I have recently had a faulty disk which needed to be replaced, so replace it I did. First, I ran mdadm --add /dev/md0…
Oleg
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GPT, grub and mdadm. sda drive replaced, raid rebuilt in recovery mode, but now server won't boot

This is how partition table loooks like: (parted) print Model: ATA TOSHIBA DT01ACA2 (scsi) Disk /dev/sda: 2000GB Sector size (logical/physical): 512B/4096B Partition Table: gpt Number …
Mladen Adamovic
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SSD fstrim on CentOS 6.x with software raid5

I have some CentOS 6.x servers. They have software raid1 and fstrim works well there. On one of the servers, I decided to do software raid5 and ext4. I can mount it with discard and there is no error message. However if I decide to run fstrim, I get…
Nick
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dracut-pre-trigger rd.md=0 removing md raid activation boot fails

The system is Fedora 22, recently upgraded from Fedora 21. The remaining kernel from Fedora 21 boots. The two kernels installed after the upgrade fail to boot. The system is an Intel S-5000 PAL with 5 SATA drives configured in raid 5 array. It has…
dan sawyer
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