Hi, I got a tiny Lenovo M720Q (i5-8400T / 8RAM / 128NVME / 1Tb 2,5" HDD) that I want to set as my home server with the ability to add 2 more drives (for RAID5 if possible) later using its two USB 3.1 Gen 2 (10gbps).

  • The OS (debian 12 + docker) will be exclusive to the nvme, I will mostly use 40/128GB of its capacity with no idea how to make use of the rest.

  • My data (medias, documents and ISO files) will resides on the HDD pool, while keeping a copy of my docs on my home pc.

I read a bit about BTRFS RAID I even experimented with it in a VM and it really got me interested in using it because of its flexibility of balancing between raid levels and the hot swapping of unequally sized drives in both stripped and mirrored arrays. However, most of what I read online predate kernel 6,2 (which improved BTRFS RAID56 reliability). So, Here I am asking if anyone here is using BTRFS RAID and if it is stable enough to use on a mostly idle server or should I stick with LVM instead. What good practices to do or bad ones to avoid?

Thank you.

  • mee@programming.devEnglish
    8·
    11 months 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 2x1TB. It’s called RAID1, but really it writes all data to 2 separate drives, that’s why the 4TB and 2x1TB example you don’t have enough to write more than 2TB on separate drives. https://www.carfax.org.uk/btrfs-usage/ is a calculator you can play with

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

    • mhz@lemm.eeOPEnglish
      1·
      11 months 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

  • joshfee@kbin.social
    2·
    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.

  • Atemu@lemmy.mlEnglish
    21·
    11 months ago

    I got a tiny Lenovo M720Q (i5-8400T / 8RAM / 128NVME / 1Tb 2,5" HDD) that I want to set as my home server with the ability to add 2 more drives (for RAID5 if possible) later using its two USB 3.1 Gen 2 (10gbps).

    Do not use USB drives in a multi-device scenario. Best avoid actively using them at all. Use USB drives for at most daily backups.

    I wouldn’t advocate for RAID5. I’d also advocate against RAID to begin with in a homelab setting unless you have special uptime requirements (e.g. often away from home for prolonged periods) or an insane amount of drives.

    I will mostly use 40/128GB of its capacity with no idea how to make use of the rest.

    I use spare SSD space for write-through bcache. You need to make the decision to use it early on because you need to format the HDDs with bcache beneath the FS and post-formatting conversions are hairy at best.

    most of what I read online predate kernel 6,2 (which improved BTRFS RAID56 reliability).

    Still unstable and only for testing purposes. Assume it will eat your data.