XigmaNAS

I wanted to create a ZFS RAID 10 equivalent - I have 6 1Tb drives and I want an available capacity of circa 3Tb from this.

I want all data duplicating across 2 drives so that 1 drive failure can never result in me losing anything.

My ZFS looks like this:

pool: NAS
state: ONLINE
scan: none requested
config:

NAME STATE READ WRITE CKSUM
NAS ONLINE 0 0 0
mirror-0 ONLINE 0 0 0
ada1 ONLINE 0 0 0
ada2 ONLINE 0 0 0
mirror-1 ONLINE 0 0 0
ada3 ONLINE 0 0 0
ada4 ONLINE 0 0 0
mirror-2 ONLINE 0 0 0
ada5 ONLINE 0 0 0
ada6 ONLINE 0 0 0

errors: No known data errors

It looks right, but is it right - I've got a circa 3Tb drive from this.

yes it looks right.

but consider this. in this configuration depending on which drives fail you can loose between 1 to 3 drives and have your data still accessible.

if you where to use raidz3 you could have any 3 drives fail and your data would still be accessible.

see this

http://www.servethehome.com/raid-calcul ... tdl-model/

raidz3 is WAY more secure for your data at the same capacity.

In fact, due to the low capacity of your drives, you are fairly safe to use raidz2 and have almost 4TB of available space

If I used raidz2 how many drives could I lose before I started losing data?

The NAS box I've got only has 2Gb of RAM, would this cause an issue using raidz2?

Could anyone explain how I would setup raidz2 please?

Primus84 wrote:Could anyone explain how I would setup raidz2 please?

from webGUI Disks|ZFS|Pools|Virtual device:

1 - select disks you want to be part of the RaidZ2
2 - select RaidZ2 as type of pool and apply.

http://wiki.nas4free.org/doku.php?id=do ... ual_device
http://wiki.nas4free.org/doku.php?id=do ... management

more info: https://forums.freenas.org/index.php?th ... oobs.7775/

If I used raidz2 how many drives could I lose before I started losing data?

You can lose two disks in Z2

Wow, previously performance was like 30mb/sec, it's now in RAIDZ2 and it's over 90mb/sec!

Is this now right:
pool: NAS
state: ONLINE
scan: none requested
config:

NAME STATE READ WRITE CKSUM
NAS ONLINE 0 0 0
raidz2-0 ONLINE 0 0 0
ada1.nop ONLINE 0 0 0
ada2.nop ONLINE 0 0 0
ada3.nop ONLINE 0 0 0
ada4.nop ONLINE 0 0 0
ada5.nop ONLINE 0 0 0
ada6.nop ONLINE 0 0 0

errors: No known data errors

yes.

btw are you using ecc memory?

No, just 2Gb of standard DDR3

please read

https://forums.freenas.org/index.php?th ... zfs.15449/

Yeah I'm gonna order some in the next month or so, is there anyway to ensure/check that the data I have copied across in the meantime is good?

(I've got another copy of the data I'm currently transferring onto the NAS and I won't delete it until I know the data on the NAS is good.)

you cant use ecc memory on most motherboards.

Ah well, does this mean this has all been a waste of time?

Should I just go back to RAID10 software RAID?

Due to horrendous software RAID10 performance I'm back on RAIDZ2 and I'll take my chances I think.

ECC/non-ECC - I wouldn't say you wasted your time. I think it is important to understand the interactions of you hardware and software. And when using a file system like ZFS, the issues that can arise using non-ECC memory.

I ran my last NAS on non-ECC for years without problem. But that doesn't mean that your NAS won't have any issues. It just means that anecdotally, people have run without ECC and been fine. (And when I rebuilt my NAS, I used ECC).

For a little more security, you could always stress test your RAM and gain some confidence. But understand the risks, do some backups, and you should be fine.

I have now sourced a replacement MB, CPU and RAM - Intel Core 2 Extreme with 4Gb of ECC RAM - slightly slower CPU than the i3 I was using but now I'll have ECC RAM when I install it tomorrow.

Once it's up and running and I import the hard drives what can I do to verify they haven't already corrupted, or would I be better restarting with them and copying everything back onto them from scratch to be sure?

You could create a md5sum for each file and compare it to make sure.


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