I am new to TrueNas & NAS’s in general and am in the early stages of setting up.
I’ve read a lot of posts, watched many YouTube videos about the various ways to setup my HDD, I think I’ve got it but just need a little push one way or the other.
Right now I have 4 HDD of equal size.
I’ll only be using my NAS for data backup, no streaming or such.
My best options as I see it are either:
1 mirror of all 4 disks, where I understand I’ll lose 75% of usable disk space but will have better risk of being able to lose 3 disks and still keep my data.
Or
2 mirrors, 2 wide, striped. Not sure about usable storage on this setup but I do know that if I lose 2 disks in the same dev here, it’s all toast.
Given just this two options, which would any of you consider as the best one, mainly in terms of resilience & future upgrade of the disks, not expansion as my NAS is 4 bay?
Again, I’m not looking at speed performance, just usability & risk management
I’d propably go for a 4 disk raidz2 instead of mirrors… 2 Disks space and 2 disks redundancy.
You can loose up to 2 disks in the vdev without data loss.
Why you are not considering the raidz2?
Whit the two 2-way mirror pool, if you lose 2 disks in the same vdev the pool Is gone, instead to lose the pool with a 4 Wide raidz2 you have to lose 3 disks.
But, if you plan future upgrade, with the raidz2 layout you must change all 4 disks to gain more space
It’s more cost intensive, since you have to replace all 4 drives before the additional capacity gets available. With mirrors you only have to replace 2 disks before the extra capacity gets available.
Cool, so I am still leaning more to a 4 wide mirror, just sacrificing some useable storage to have extra peace of mind.
like I’ve stated, I do not need anything fancy at the moment, just storage space, maybe in the future, that’s why I have gone down the route of a NAS after ditching Windows and it’s storage spaces feature.
At this point you can also evaluate to stay with a 3 wide mirror, and keep the fourth disk as spare, detached, away from the nas.
And in case, sometimes, just making on it a from scratch replication (also viable with a good sata-usb adapter); ok, you will sacrifice 1 disk fault tolerance, but you will not “consume” this disk so will be ready to be promoted as replace if one of the other fails, and on it will be also present the data to restore in very catastrophic case
After some more research, head scratching and taking on board points made here, I have made the decision to setup as RaidZ2.
I really liked the less risky route of a 4 wide mirror but then considered how quick I’d probably use that 25% storage, so moving from that to the obvious ‘double the storage’ without any more initial outlay, it was only between RaidZ2 & 2x2 Mirror.
In my own head the resilience of the 2x2 mirror seemed worse than the RaidZ2 even though it’s the same number of drive loss before fail I just think, worry, that just my luck, the two fails would be in the same mirror pair and that’s final, at least with RaidZ2 there a chance for recovery.
For future expansion, well you can’t have it all ways, when it comes to it I’ll have to take the hit at upgrading all the drives before seeing a storage increase but I could purchase each drive as and when I can that way at least they’d be different batches.
cheers for everyone’s help here, I dare say I’ll be back with more questions further down the road.
