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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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How do I list which drives are part of each RAID array?

I have a linux software RAID using md. I want to list all of my RAID arrays and each hard drive attached to them. Is there an easy way to do that?
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Implementing Linux fstrim on SSD with software md-raid

I'm currently building a new Ubuntu 13.04 server with 2 256GB SSDs in a raid mirror to run a MariaDB instance. We typically place LVM on top of dm-crypt encryption on top of an md raid 1 array, but haven't used SSDs in this setup previously. My…
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Linux mdadm software RAID 6 - does it support bit corruption recovery?

Wikipedia says "RAID 2 is the only standard RAID level, other than some implementations of RAID 6, which can automatically recover accurate data from single-bit corruption in data." Does anyone know if the RAID 6 mdadm implementation in Linux is one…
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How do you monitor the health of a mirrored disk in Windows?

I have a Mirrored Dynamic disk on my Windows 2003 Server. How do you monitor the health of the volume? Is there a way to have the server send an email when there is an issue with the volume? Is there a way to have the server run S.M.A.R.T.…
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Deciphering continuing mpt2sas syslog messages

Summary I have been getting these cryptic messages in syslog since I installed some new hardware and I can't figure out what the problem is, if it's serious, or what to do about it. They're from the new SATA HBA and they follow a pattern. I will get…
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Device: /dev/sda [SAT], 1 Currently unreadable (pending) sectors

I have a software RAID 1 array on RHEL. I am getting this error emailed to me each morning: Device: /dev/sda [SAT], 1 Currently unreadable (pending) sectors When I run a test on sda (or sdb) everything appears to pass. Am I missing…
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How to recover an mdadm array on Synology NAS with drive in "E" state?

Synology has a customized version the md driver and mdadm toolsets that adds a 'DriveError' flag to the rdev->flags structure in the kernel. Net effect - if you are unfortunate enough to get a array failure (first drive), combined with an error on a…
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KVM guest io is much slower than host io: is that normal?

I have a Qemu-KVM host system setup on CentOS 6.3. Four 1TB SATA HDDs working in Software RAID10. Guest CentOS 6.3 is installed on separate LVM. People say that they see guest performance almost equal to host performance, but I don't see that. My…
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Convert linux software raid from raid5 to raid6

I currently have a file server with 3 1.5TB disks in a RAID5 array. Since it's pretty much full, I got three additional disks (also 1.5TB each). Now I'd like to switch to RAID6 since 6TB space is enough and I'd like to have the increased safety of…
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How to do the equivalent of Synology Hybrid Raid on Linux myself?

http://forum.synology.com/wiki/index.php/What_is_Synology_Hybrid_RAID%3F Synology is just Linux and uses LVM. How do their tools automate LVM to achieve what they call their Hybrid Raid?
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Easy to expand Linux software RAID 5 with XFS. Best practices?

I use my Ubuntu machine as a file server for Windows/Linux/Mac clients using a Samba share. I need it to be easily expandable by just adding more hard drives without having to move any data back and forth. This is how I have done it so far. I have…
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Degraded Array. RAID 6 with three disk failure

I have an array of disk with RAID 6 and 16 Drives. Days ago three disk failed and the Array was marked as Degraded. I cannot access the data and I cannot boot into the Operative System. I need access to the data but I cannot do anything. Any advice?…
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Is RAID5 more robust than RAID1

I am about to replace an old hardware RAID5 array with a Linux software RAID1 array. I was talking to a friend and he claimed that RAID5 was more robust than RAID1. His claim was that with RAID5, on read the parity data was read to make sure that…
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LVM volume group shared between KVM/libvirt host and guests: is this a bad idea?

I have just built a shiny new KVM/libvirt-based virtual machine host, containing 4 SATA II hard drives, and running CentOS 5.5 x86_64. I have decided to create virtual machine disks as logical volumes in an LVM volume group managed as a libvirt…
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mkfs Operation Takes Very Long on Linux Software Raid 5

I've set-up a Linux software raid level 5 consisting of 4 * 2 TB disks. The disk array was created with a 64k stripe size and no other configuration parameters. After the initial rebuild I tried to create a filesystem and this step takes very long…
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