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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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Do disks in Raid-1 function outside of the raid?

Raid-1 is mirroring two disks (if I haven't messed up completely here :p). Does that mean that I could take one disk out and put it into another machine and it would work like a normal disk? Or does it still only work in the raid? I can understand…
Svish
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Boot Debian while RAID array is degraded

Recently, I came across Ubuntu Server install. During install, it asked me whether or not to allow booting system from degraded RAID array (probably because I installed system onto RAID1 /dev/md0 device). This is mighty-useful option for unattended…
mr.b
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Why has open-iscsi two times slower writes than Samba via 10G Ethernet?

On my local file server I have raid-6 on 7x HDD drives. dd if=/dev/zero of=tempfile bs=1M count=2048 conv=fdatasync Local speed test gives me 349 MB/s write speed. Remote writes to Samba from SSD (>2Gb/s read speed) gives me 259 MB/s writes. But…
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Why does a raid 10 device need to be initialized?

When creating a linux software raid device as a raid10 device, I am confused why it must be initialized. The same question applies for raid1 or raid0, really. Ultimately most people would put a file system of some sort on top of it, and that…
Michael Graff
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How to make a Linux software RAID1 detect disc corruption?

This is one of the nightmare days: A virtualized server running on a Linux SW-RAID1 runs a VM that exhibits random segfaults in seemingly random codechunks. While debugging I find that a file gives different md5sums on each and every run. Digging…
Paul
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Is it safe to shutdown a machine while rebuilding/recovering/growing a RAID5 array that was built with mdadm

I have recently started a recovery on my 5-drive RAID in my file-server, and it says it'll take 691+ minutes to complete. I was wondering what would happen to the process if the machine lost power - say in a blackout? Would I need to restart the…
jsnfwlr
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How to attach an existing RAID1 to a fresh Linux system?

I have a RAID1 currently operating on a single hard drive (yes, the mirror is absent). Is it possible to reorganize my system using the following algorithm? I set up another single-disk RAID1 (onto another HDD of the same type), partition it and…
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Storage server - Swapping SAS HBA card for a different model

TL;DR Server's original SAS HBA (PCIe card) does not support transparent passthrough, which is desired, as I want the OS to manage the disks (ZFS). At my company, we have an Intel SSR212MC2 server (spec sheet) with SRCSAS144E RAID controller. The…
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write hole: which RAID levels are affected?

In my journey to understanding the advantages of RAIDZ, i came across the concept of write hole. As this page explains, a write hole is the inconsistency you get among the disks of the array, when the power is lost during a write. That page also…
Mario Vitale
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Software vs. Hardware RAID1 (Mirror)

How does the Software Mirror in Windows Server systems compare to an affordable hardware/BIOS RAID? I've had some rather bad experiences with onboard hardware RAID controllers, so I would want to avoid them in the future. OTOH I've used XP's and…
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Remove "faulty state" in RAID 1

I wonder if there is any possibility to remove the state "faulty" in a RAID 1 if (for example) someone failed the wrong hard disk. I already searched for answers with Google and found several tutorials with re-creating the array and adding…
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mdadm: Which disk is being rebuilt?

I noticed my software RAID1 degraded, and wanted to figure out which of the two disks in the array is being rebuilt/re-synced since they both show as being up. I am hoping someone can shed some light on this, if it's even possible to figure out…
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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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Are different RAID cards setups compatible?

I'm setting up a new NAS/SAN system with RAID5, and I was wondering if going the software or hardware RAID way because I had this question in mind: If my hardware-RAID card fails, will I need to substitute by one exactly the same, same brand is…
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