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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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Poor Linux software RAID 5 performance with NCQ

While salvaging a 2-disk failure in my 3-disk RAID 5 setup, I happened to notice reconstruction was faster with NCQ disabled (~90M/sec) than with the NCQ enabled (~50M/sec). Running bonnie++ to benchmark the two configurations also revealed…
Owen Fraser-Green
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Configure Windows RAID-5 "drive failed" timeout?

Background When a hard-drive controller detects an error, and needs to remap a sector, the drive normally becomes unresponsive for the seconds (or possibly minutes) it takes to try to complete the re-mapping. With the drive no longer responding, a…
Ian Boyd
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Can I use dmraid instead of md (mdadm) to make software RAID-1 and RAID-1+0 volumes?

On a related question about SSDs and TRIM (see: Possible to get SSD TRIM (discard) working on ext4 + LVM + software RAID in Linux? ), it turns out that dmraid may now (or shortly) support TRIM on RAID-1. Typically, we've used md (via mdadm) to…
Don MacAskill
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Where should my swap partition/s live when using software RAID1? Performance? LVM?

When I search around for example RAID1 installations, it seems that admins tend to place their swap partition under RAID1. To me, it is more intuitive to have two disks, each with a large partition for use by RAID1 and the system partition and with…
andyortlieb
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Can Windows 7 do software RAID 10 (1+0)

Can Windows 7 do software RAID 10 (or RAID 1+0 depending on terminology)? There appears to be a lack of information about software RAID for Microsoft Windows products. Even a search of the microsoft.com offers zero articles about the subject, just a…
PP.
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Linux Software Raid 10 hung after 1 drive failed, mdadm will not let me force remove the faulty device

I have a Linux software raid 10 setup consisting of 5 RAID 1s (Two drives per mirrored setup) and a RAID 0 across all 5 RAID 1 pairs. To test that none of the drives were going to fail quickly under load I used badblocks across the RAID 0 with a…
ScottZ
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USB drive RAID array

I am trying to contemplate how stupid an idea this would be... I was inspired by some foolish fellow, who soon after the release of Mac OS X 10.0 took 5 USB floppy drives, plugged them into his iMac, and set up a RAID5 array on them. Floppy RAID…
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How to add hot spare to software RAID1?

I have a CentOS 7 server. It is running a software RAID 1 mirroring three disks. I want to add a 4th disk to act as a hot spare. My intention is that in the event of a failure of one of the three disks being mirrored that the hot spare would…
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Do any software RAID solutions support the TRIM command?

This is a broad question -- I'm not asking about a particular RAID level or OS.
Fantius
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Amazon AWS Ephemeral disks and RAID1

Some AWS instances have "ephemeral disks" attached, which are much faster than EBS. But ephemeral disks will be blank and uninitialised when your instance is stopped and started. The data on disk generally survives an instance reboot…
Criggie
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Hetzner's installimage script, RAID1 hard drives + SSD

I just purchased a server from Hetzner, with two 4TB hard drives and one 1TB SSD. I want to setup the two hard drives (/dev/sda & /dev/sdb) in RAID1 and install the OS on them, and have the SSD (/dev/sdc) as an extra drive. Until now, all my…
Tim Autin
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EMC ScaleIO vs Starwind Virtual SAN

I'm setting a test lab to evaluate best solution for future production use. The production farm intended for an SMB, so budget is present, but it is also limited. Goal for production: 3 hyperconverged servers with Windows Server 2012 R2 failover…
Eugene
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Using software-RAID vs "firmware"-RAID (a.k.a. FakeRAID)

We recently bought a tower server on which I want to install Debian. I thought the device had hardware RAID, as I could see a BIOS screen. As it turns out, it's still a software RAID. When I configure the RAID drives through that firmware, I can…
user1496984
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Linux file system cache: Move data from Dirty to Writeback

My software RAID can write 800 MB/s sustained. I see that happening when cat /proc/meminfo |grep Writeback: returns > 2 GB. However, most of the time the writeback is round 0.5 GB which gives a performance around 200 MB/s. There is plenty of data to…
Ole Tange
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What would happen if I did a raid on a SSD and an HDD?

I am building another server (cheap) and would like to go with a 256GB SSD drive for my boot and data. This will be enough for my needs, but just having one SSD scares me for a couple of reasons. If I did a mirror raid with a SSD and an HDD, what…
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