Re: [gentoo-user] NAS suggestions for home user

[Wols Lists]

On 30/09/21 22:50, Mark Knecht wrote:
> I'm in the study phase on some sort of NAS backup system for my home.
> I'll be building (or buying) a new desktop/server machine in the next
> few months - my i980 machine doesn't have the right instruction set for
> running Tensorflow anymore - so I want to figure out backups before I
> put together the new machine.

Okay, your NAS box is going to be shut down most of the time? Why not
re-purpose your old box as the NAS? If it was running a lot, I'd be
concerned about the power consumption,but here it sounds okay.
>
> I have about $400 credit at NewEgg and would like to keep my additional
> costs on the NAS down to about $100-$200. I expect the new machine to
> probably be 4TB RAID but it would be quite a while before that gets
> filled up.

If that includes buying new drives, you're pushing your luck here ... a
new "suitable for raid" 4TB drive will probably blow that budget in one hit!
>
> What do I need to be thinking about? Do I need 8TB in the NAS box?

Ummm... I'd be inclined to buy a single 8TB drive. It's not much more
than the 4TB - I'd suggest suggest Seagate Ironwolf. The Tosh N300s
aren't bad afaik, but I've no personal experience. You could get a WD
Red Pro, but do NOT get a plain Red, and given the way they've mucked
people about I personally wouldn't get a WD.

> Are 2 or 4 bay NAS boxes generally RAID? I do backups today about once a week.
> I do not currently keep any snapshots.

2-bay will be mirrored, 4-bay is normally raid-5

> I just back up files so over time
> the backup carries a lot of stuff that I don't need anymore and I have
> to go clean it up if I run out of space.

Get that 8TB Ironwolf/N300, format it btrfs (it pains me to say that
:-), and set up your backup to do an "in place" rsync then snapshot the
volume.

That way, each backup will be an incremental, but the snapshot will give
you a full backup. Think of it like git, it will store the current
state, with diffs so you can checkout any previous state if you want.

Just MAKE SURE the drive never actually fills up - btrfs has an
appalling rep for surviving a disk full with snapshots.

If you need more space you can then think about getting a second (and
third, and fourth) 8TB drive and going to raid or just adding them to
the btrfs. Again, just remember that, at the moment, btrfs parity raid
also has a pretty appalling rap. Mirroring is fine.
>
> The NAS would be turned off most of the time. If I need to use it I'll
> just power it up.
>
> I've been looking at a few software solutions based on another thread
> here but so far nothing has excited me so recommendations for what makes
> sense for high reliability home backup is of great interest, especially
> if it helps me somehow in cleaning up the backups after deleting stuff
> on my main machine on purpose and therefore not needing it on the backup.
>
> Thanks in advance for any ideas.

Take a read of the raid wiki -
https://raid.wiki.kernel.org/index.php/Linux_Raid

In particular the overview section. My current (new) setup is ext4, over
lvm, over mirror raid, over dm-integrity, over two IronWolves. I'm
planning to add a Barracuda and go raid-5, but not without a solid
backup first !!!

Make sure you read the warnings, and the timeout mismatch section! It
talks about Barracudas, and WD Reds!

On a different topic, I don't know anything about it but some file
systems do block level de-duplication - zfs I believe for one. That way,
you can create your backups in dated directories, and the filesystem
will store each duplicated file only once, without you having to worry
apart from maybe having to trigger a manual de-duplicate once in a
while. But with 8TB that won't be often.

Cheers,
Wol