I am planning on creating a home server with either 2 (RAID1) or 3 (RAID5) HDDs as bulk storage and 1 SSD as bcache.
The question is, what file system should I use for the HDDs? I am thinking of ext4 or xfs, as I heard btrfs is not recommended for my use case for some reason.
Do you all have some advice to give on what file system to use, as well as some other tips?
The BTRFS thing is cutting the power or losing the disks in the middle of a write which corrupts your data. If you don’t think that will be a problem then BTRFS is fine. I recommend ZFS personally, but it sounds like you want to use mdadm instead so basically anything will work.
If you might need to shrink your filesystem later then avoid XFS. EXT4 is relatively featureless but ol’ reliable. ZFS is good for long term data integrity and protection. BTRFS is similar to ZFS. BcacheFS is new but like a swirl of EXT4 and BTRFS. Just pick the one with the features you want.
Powerloss might happen as I don’t have a ups.
And when it comes to mdadm, it just happens to be the first and only redundancy tool I know. I am however open to learn and try new things.
ZFS seems interesting, but: I read that ZFS would require quite a lot of RAM, and I was going for 32 GBs only, would it be enough?
1 GB of RAM for every TB of storage is recommended but you can do with way less for ZFS.
ZFS doesn’t require lots of RAM, more RAM just improves the caching (ARC) it can do. You can set ZFS to use all unused RAM as ARC, so it doesn’t interfere with other services running on the same PC. I ran ZFS with lots of VMs on an old office PC with 16GB RAM and it was still able to max out a 10gig nic.
ZFS doesn’t require a lot of RAM, but it will use more RAM if it’s available. 32G would be plenty for a home setup. I think my home file server has 24 or 32G of RAM and ZFS. If it’s important data then stick to what you know; there’s nothing wrong with mdadm.