spare HDD on RAID5 with nas4free

[tynolol]

Hello everyone,

I'm French so excuse me about my poor english

I would like to know if it is possible to add a spare HDD on a RAID5 (I mean a HDD which would be used when one of the others HDD will broke down)

Could explain me how to?

Thks
best regards

[b0ssman]

it would be much better to use raid6 or raidz2 than raid5 + spare.

[tynolol]

Why ?? I don´t know those two kind of raid..

[b0ssman]

2 drive redundancy

see wiki article about raid levels
http://en.wikipedia.org/wiki/RAID

[tynolol]

Ok i'll read it thank you.

But my raid 5 is already created (but there is not data yet on it)

[b0ssman]

also read

http://www.zdnet.com/blog/storage/why-r ... n-2009/162

[tynolol]

Ok I read both. Thank you,

I'll delete my raid5 and create a new raid. I have 5 3To HDD, which one of RAID6 or RAIDZ2 do you advice me?

thks

[b0ssman]

that depends.

raidz2 is far superior, but you should have ecc ram for that.

here is an article to read for that.

http://wiki.nas4free.org/doku.php?id=faq:0144

[raulfg3]

Ok i'll read it thank you.

But my raid 5 is already created (but there is not data yet on it)

better if you use ZFS ( raidZ) is more robust and forum are full of RAID problems, please consider to use ZFS.

[tynolol]

How to create ZFS on nas4free?? I format my 5 HDD in ZFS pool device, then I go in menu disk-->ZFS-->pool-->virtual device and which type should I choose?

edit : I guess double parity RAIDZ ??

[b0ssman]

yes

[tynolol]

and then? is it created?

edit : what are the dataset, volumes, snapshots and configuration tabs? should I do something in those menus??

[ChriZathens]

You already mentioned that you wanted to have a raid with 5 disks and 1 disk spare..
So you have a total of 6 disks.
b0ssman suggested that you use all 6 disks to create a raidz2 array
So you should format all 6 disks (ZFS pool device) and then, yes, the thing you need in vdev is double parity RAIDZ
Afterwards you will create a pool using this vdev

[b0ssman]

read this

http://www.mini-itx.com/projects/nas4free/?page=2

[ChriZathens]

And some more links:
vdevs: Disks|ZFS|Pools|Virtual device
pools: Disks|ZFS|Pools|Management

[tynolol]

Ok I did all of it ! thanks you 3 of you ! I am asking to myself what are the others menus (dataset, volumes, snapshots and configuration tabs) used to?

[tynolol]

Actually I am surprised because it's very quick to create RAIDZ-2 where as RAID5 take several hours/days while "rebuilding" step

[ChriZathens]

You will need to read a bit about datasets and volumes: head to the wiki: http://wiki.nas4free.org/doku.php
But, IMHO you can ignore datasets and volumes for now (i personally don't use them)
If you are impressed by the speed raidz gets created, you will be more impressed if you need to replace a disk (I hope you won't need to, lol..)
But IF it happens, you will see that rebuilding in ZFS is much faster and much less stressful for your disks

[tynolol]

lol like you said I cross my fingers not to have to, but it will happen sooner or later. Can you explain me how to replace a disk in ZFS?

[ChriZathens]

How do I remove / replace a failed disk in a ZFS array ?

As I said, there is a lot of reading to do...

[b0ssman]

a lot of your questions are answered in the faq

http://wiki.nas4free.org/doku.php?id=documentation:faq

please read that before.

[tynolol]

Ok I will read it. Thank you !

[tynolol]

How to set a RAID 6 on nas4free? I can't see raid 6 in software RAID menu..

[b0ssman]

there isnt a software raid6 under freebsd.
there is raidz2 as it is the better solution.

linux supports raid6 as well as hardware raid controllers.