How dumb would it be to run single-node ceph? (lemmy.ml)

submitted 8 months ago by jkrtn@lemmy.ml to c/selfhosted@lemmy.world

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I really want to run ceph because it fits a number of criteria I have: gradually adding storage, mismatched disks, fault tolerance, erasure encoding, encryption, support out-of-the-box from other software (like Incus).

But then I look at the hardware suggestions, and they seem like an up-front investment and ongoing cost to keep at least three machines evenly matched on RAM and physical storage. I also want more of a single-box NAS.

Would it be idiotic to put a ceph setup all on one machine? I could run three mons on it with separate physical device backing each so I don't lose everything from a disk failure with those. I'm not too concerned about speed or network partitioning, this would be lukewarm storage for me.

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[-] MangoPenguin@lemmy.blahaj.zone 3 points 8 months ago

You end up wasting a ton of space though because each vdev has its own parity drives.

[-] bastion@feddit.nl 1 points 8 months ago

No matter what setup you use, if you want redundancy, it'll cost space. In a perfect world, 30% waste would allow you to lose up to 30% of your disk space and still be OK.

..but that extra percentage of used space is the intrinsic cost.

[-] avidamoeba@lemmy.ca 1 points 8 months ago* (last edited 8 months ago)

What you lose in space, you gain in redundancy. As long as you're not looking for the absolute least redundant setup, it's not a bad tradeoff. Typically running a large stripe array with a single redundancy disk isn't a great idea. And if you're running mirrors anyway, you don't lose any additional space to redundancy.

[-] SidewaysHighways@lemmy.world 3 points 8 months ago

Yep I feel this way.

No point in pricing a single HDD because I'm shooting for parity on every vdev I spin up.

[-] MangoPenguin@lemmy.blahaj.zone 2 points 8 months ago

Fair enough, it does add a good chunk of power usage though as HDDs are pretty power heavy at 5-7W or so.

this post was submitted on 07 Mar 2024

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