Homeserver Storage considerations - Suggestions please

seiichiro0185 · 2010-02-01 04:32:04

Hi all,

I'm currently upgrading my homeserver from an old Via-C7 with 1 HDD to a new system. The new one is a Atom D510 in the nice Chenbro ES34069 Case (Mini-ITX with 4x Sata Hotswap). Hardware-wise all is working out nicely so far, and Arch runs perfectly on the box. Now here is my Problem: How to layout the storage software-wise (lvm/raid/whatever).

What I have:

1x 2TB HDD holding the data from the old server
3x 1.5TB HDD free
all attatched to the server

What I want:

The drives should be assembled in an array that provides the following:
- Accessible as one single "drive"
- encrypted at block level (dm-crypt / luks)
- provides redundancy (array survives failing of at least one drive)
- array is extensible (Disks can be swapped for bigger ones / new disks can be added later [doing this online would be optimal])
- be as performant as possible
- it must be possible to first build the array out of 3 Disks, copy the data from the 4th to the array and then add the 4th Disk to the array

The System has to be linux/arch, since I use software that only runs on linux (VDR), so no switching to solaris/BSD... possible
The encryption is a must for me, I'm not here to debate if its neccessary or not

What I tried/considered so far:

- Linux Software RAID 5
Pros:
- extensible, one can reshape the array online
- redundant
- encryption layer on top is possible
- good usage of the aviable space
Cons:
- questionable reliability (raid 5 write hole problem, silent data/parity corruption)
- weak write/rewrite performance

- Linux Software Raid 10
Pros:
- faster than RAID 5
- excryption on top possible
- redundant (up to 2 disks can fail, depending on which)
Cons:
- loosing half of the HDD-space for redundancy
- not extensible (raid10 driver doesn't support reshaping)

- ZFS (through ZFS-Fuse)
Pros:
- raidz does RAID 5 but right (no write hole or silent data corruption problems)
- extensible, even online
Cons:
- stability of zfs-fuse is questionable, dont know how stable it is
- no encryption layer on top is possible
- writes are quite slow from my tests (this is partly cause of the point above, every disk is encrypted seperately -> to much to handle for the Atom)

- 2x Software RAID 1 with LVM on top
Pros:
- extensible, even online
- should be quite fast
- encryption layer on top is possible
Cons:
- loosing half of HDD-space for redundancy

So thats What I have considered so far. What is the arch community using for similar setups? Any suggestions of other methods (BTRFS??) that coud statisfy my needs? Which of the above would you / have you choosen?

I'm thankfull for any constructive suggestions
seiichiro0185

Arch Linux

#1 2010-02-01 04:32:04

Homeserver Storage considerations - Suggestions please

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