Seeking advice about BTRFS RAID

Comments

• mee@programming.dev ⁨1⁩ ⁨year⁩ ago

  I would continue to say don’t use RAID56. You can use RAID1, which will give you the sum of all your drives divided by 2 in usable space. As long you’re not matching say a 4TB and 2x 1TB.

  btrfs.readthedocs.io/en/latest/Status.html#block-… They still list RAID56 as unstable on the docs.

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  • mhz@lemm.ee ⁨1⁩ ⁨year⁩ ago

    Thank you for the links, I will hold on using RAID and stick with BTRFS single until I upgrade my storage to higher capacity or my server to something with more reliable SATA slots

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• yote_zip@pawb.social ⁨1⁩ ⁨year⁩ ago

  You can also use MergerFS+SnapRAID over individual BTRFS disks which will give you a pseudo-RAID5/6 that is safe. You dedicate one or more disks to hold parity, and the rest will hold data. At a specified time interval, parity will be calculated by SnapRAID and stored on the parity disk (not realtime). MergerFS will scatter your files across the data disks without using striping, and present them under one mount point. Speed will be limited to the disk that has the file. Unmitigated failure of a disk will only lose the files that were assigned to that disk, due to lack of striping. Disks can be pulled and plugged in elsewhere to access the files they are responsible for.

  It’s a bit of a weird-feeling solution if you’re used to traditional RAID but it’s very flexible because you can add and remove disks and they can be any size, as long as your parity disks are the largest.

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• joshfee@kbin.social ⁨11⁩ ⁨months⁩ ago

  The stability issues with RAID5 on BTRFS tend to be blown out of proportion. I've been using it for my home server with mixed drives of ~50TB raw for about 5 years without any issues. I use it for the same benefits you've noted, mainly support for ad hoc expansion while still maximizing usable space. Until bcachefs is released BTRFS is the only filesystem I've seen with these features.

  That said, the mentioned stability issues, particularly the write hole, ARE real and possible. I wouldn't use it in a commercial production scenario or for data I couldn't stand to lose. Anything I care enough about has off-site backups, and my server runs on a UPS to mitigate issues from power outages. But for my purposes it's worth the minor risk for the benefits.

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• Moonrise2473@feddit.it ⁨1⁩ ⁨year⁩ ago

  I understood that software raid on USB is dangerous as sometimes the drives can get offline for a few seconds due to current fluctuations and then will lose the sync. Maybe it’s ok for files that don’t get accessed too often, like video file backups

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  • poVoq@slrpnk.net ⁨1⁩ ⁨year⁩ ago

    In my experience there are often issues with sata ssd over USB, but slower HDD seem to work fine. With btrfs I would set up a regular scrubbing job to find and fix possible data errors automatically.

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• poVoq@slrpnk.net ⁨1⁩ ⁨year⁩ ago

  There is little benefit over using raid1 IMHO since you can quite easily match discs to utilize all the space as others have already mentioned.

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• Decronym@lemmy.decronym.xyz ⁨1⁩ ⁨year⁩ ago

  Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I’ve seen in this thread:

  Fewer Letters	More Letters
  RAID	Redundant Array of Independent Disks for mass storage
  SATA	Serial AT Attachment interface for mass storage
  SSD	Solid State Drive mass storage

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