Have I made what I think I've made?!

Primus84 · Post by **Primus84** » 12 Mar 2015 22:21

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.

Post by **b0ssman** » 13 Mar 2015 04:07

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.

Post by **b0ssman** » 13 Mar 2015 04:10

see this

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

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

Post by **ChriZathens** » 14 Mar 2015 01:42

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

Primus84 · Post by **Primus84** » 14 Mar 2015 09:25

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?

Post by **raulfg3** » 14 Mar 2015 10:09

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/

Post by **crowi** » 14 Mar 2015 10:13

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

You can lose two disks in Z2

Primus84 · Post by **Primus84** » 14 Mar 2015 10:35

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

Post by **b0ssman** » 14 Mar 2015 10:51

yes.

btw are you using ecc memory?

Primus84 · Post by **Primus84** » 14 Mar 2015 10:52

No, just 2Gb of standard DDR3

Post by **b0ssman** » 14 Mar 2015 10:58

please read

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

Primus84 · Post by **Primus84** » 14 Mar 2015 11:09

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.)

Post by **b0ssman** » 14 Mar 2015 11:18

you cant use ecc memory on most motherboards.

Primus84 · Post by **Primus84** » 14 Mar 2015 11:20

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

Should I just go back to RAID10 software RAID?

Primus84 · Post by **Primus84** » 14 Mar 2015 21:29

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

Captain Ron · Post by **Captain Ron** » 15 Mar 2015 14:20

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.

Primus84 · Post by **Primus84** » 18 Mar 2015 21:46

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?

Post by **b0ssman** » 19 Mar 2015 06:29

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

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