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Questions tagged [software-raid]

RAID solution handled by the operating system.

Software RAID is implemented in the OS. It uses CPU to handle the RAID setup. It is cheaper than hardware raid. It often doesn't support features which you can find with hardware raid like:

  • hot spare
  • fast rebuilding of an array
  • hot swapping
  • high write throughput

Another problem is that it uses the CPU and memory of the computer to perform all the tasks (hardware raidcards have a special cpu and memory for this task). Therefor generating more load on your system.

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High I/O latency with software RAID, LUKS encrypted and LVM partitioned KVM setup

I found out a performance problems with a Mumble server, which I described in a previous question are caused by an I/O latency problem of unknown origin. As I have no idea what is causing this and how to further debug it, I'm asking for your ideas…
aef
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How to create a software raid5 array without a spare

I am trying to create a software raid5 array using mdadm: $ linux # mdadm --create --verbose /dev/md0 --level=5 --raid-devices=4 --spare-devices=0 /dev/sda1 /dev/sdb1 /dev/sdc1 /dev/sdd1 mdadm: layout defaults to left-symmetric mdadm: chunk size…
Yannick Motton
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What effect does RAID stripe size have on read-ahead settings?

I'm trying to figure out the correct read-ahead values to set on a RAID10 array, and I'm wondering if the RAID stripe size should factor into my considerations. I've heard conflicting information about this in the past. I once heard that you should…
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Is it necessary to have RAID in a virtual machine?

I have a Windows 2008 Enterprise on RAID 10 running Active Directory, Hosted Exchange, and a web server on HyperV VMs. Do I need a virtual RAID for Exchange? If so, why? Edit: thanks everyone for the answer. Very helpful!
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What is the meaning of the 'Personalities' feature under /proc/mdstat

On some systems I see this : Personalities : [linear] [raid0] [raid1] [raid10] [raid6] [raid5] [raid4] [multipath] [faulty] md1 : active raid1 sdb1[1] sda1[0] 10485696 blocks [2/2] [UU] md2 : active raid1 sdb2[1] sda2[0] 477371328…
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does the *physical* order/location of drives in a mdadm-managed RAID-10 array matter?

i've setup a 4-drive RAID-10 array using mdadm-managed, software-raid on an x86_64 box. it'd up & running and works as expected, cat /proc/mdstat md127 : active raid10 sdc2[2] sdd2[3] sda2[0] sdb2[1] 1951397888 blocks super 1.2 512K…
user114604
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e2fsck / resize2fs problems

I've got 6 drives (each 1.5T, all same model and firmware revision) that are part of a RAID5 array. The RAID5 makes a LVM volume group and a logical group. The latter contains only one ext3 partition. I've recently ran: e2fsck -f /dev/vg03/lv01 &&…
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Linux fails to reassemble RAID array after disk upgrade

I have an Ubuntu (9.10) machine with 4 SATA disks. Each disk is partitioned identically, with the first few gigabytes set aside for a RAID 1 array (/dev/md0) for the boot volume, and the remainder set aside for RAID 5 (/dev/md1). Recently, I…
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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…
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Linux Software Raid runs checkarray on the First Sunday of the Month? Why?

It looks like Debian has a default to run checkarray on the first Sunday of the month. This causes massive performance problems and heavy disk usage for 12 hours on my 2TB mirror. Doing this "just in case" is bizzare to me. Discovering data out of…
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Boot from software RAID 1 on Windows Server 2008 R2

I have a Windows Server 2008 R2 x64 system with a single hard drive, and I have a spare hard drive of same size/model that's not being used. I was thinking about dropping in the new drive and setting it up as RAID 1 (mirroring) to achieve poor…
Justin Grant
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Should I worry about the integrity of my linux software RAID5 after a crash or kernel panic?

I have a dual core Intel i5 Ubuntu Server 10.04 LTS system running kernel 2.6.32-22-server #33-Ubuntu SMP with three 1TB SATA hard drives set up in a RAID5 array using linux md devices. I have read about the RAID5 write hole and am concerned: if my…
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Linux boot on a raid1 software raid?

I am trying to convert my single disk boot to a raid1 boot So far here is what i have: I sucessfully create the raid 1 as degraded with the new drive alone, I copied all the data on it I can mount that raid 1, see its files etc I already have a…
azera
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2 drives, slow software RAID1 (md)

I've got a server from hetzner.de (EQ4) with 2* SAMSUNG HD753LJ drives (750G 32MB cache). OS is CentOS 5 (x86_64). Drives are combined together into two RAID1 partitions: /dev/md0 which is 512MB big and has only /boot partitions /dev/md1 which is…
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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…
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