Type of Volume for backup?

[Booyaah]

I'm new to freenas and just built a new machine, anyways I have 4 disks (6 TB each) in a RAID 10 volume right now and I wanted to setup a nightly backup on my 5th disk (also 6 TB) right now. Eventually I'll add a 2nd disk to the backup volume when I get closer to 50% of total disk space usage on the RAID 10 volume, but for now I'm just sticking with a single WD Green.

Anyways my question is when I create a new volume for the backup, the only real option I have is for Stripe (yes I see log/cache as well but those aren't what I want). When I eventually add a 2nd disk to extend my backup volume, is that going to put it in a RAID0 configuration? Because I don't really want to use any RAID for my backup...JBOD would be fine, but I don't care about extra speed from RAID or want to have to risk a failure due to parity bits or what not.

I was thinking, would it be best just to destroy the existing 1 disk backup volume when I get a 2nd disk, then re-create a new 2 disk volume, and then do a full backup to the new backup volume, and just pray I don't get a disk failure? I am using an IBM ServeRaid M1015 card in IT mode, would it just be best to JBOD the backup drives only maybe through the HBA? (not even sure that's possible in IT mode)

Cause I don't see any kind of option like that in the FreeNAS gui, is there a command line option for it?

 

[Ericloewe]

You're all over the place.

Are you using anything other than ZFS to do what you called RAID10? If so stop right there. Destroy that and make a proper pool, first by adding the two striped disks and then adding a mirror to each one of them.

However, why would you want striped mirrors instead of RAIDZ2? I'll venture a guess that speed is not your primary concern. In that case, RAIDz2 is much, much better than RAID10-like solutions.

"Don't want to risk a failure due to parity bits or what not."? Look, I mean no offense, but you obviously know little about the topic, just enough to make very bad decisions.

I'm going to give you the link to Cyberjock's presentation, which will hopefully answer all your unvoiced questions and certainly answers all asked questions:

http://forums.freenas.org/index.php...ning-vdev-zpool-zil-and-l2arc-for-noobs.7775/

 

[Booyaah]

I think you have misunderstood me. No I am not doing hardware RAID10, I am striping 2 mirrors in ZFS together. This might clear things up:

Code:

[root@freenas /mnt]# camcontrol devlist
<ATA WDC WD60EFRX-68M 0A82> at scbus0 target 0 lun 0 (da0,pass0)
<ATA WDC WD60EFRX-68M 0A82> at scbus0 target 1 lun 0 (da1,pass1)
<ATA WDC WD60EFRX-68M 0A82> at scbus0 target 2 lun 0 (da2,pass2)
<ATA WDC WD60EZRX-00M 0A80> at scbus0 target 3 lun 0 (da3,pass3)
<ATA WDC WD60EFRX-68M 0A82> at scbus0 target 4 lun 0 (da4,pass4)
<SanDisk SDSSDRC032G 3.1.0> at scbus5 target 0 lun 0 (ada0,pass5)
<Verbatim STORE N GO 1.01> at scbus8 target 0 lun 0 (pass6,da5)

[root@freenas /mnt]# zpool create mont-vol01 mirror da4 da1 mirror da0 da2 cache ada0
cannot mount '/mont-vol01': failed to create mountpoint

[root@freenas /mnt]# zpool status
pool: mont-vol01
state: ONLINE
scan: none requested
config:

NAME STATE READ WRITE CKSUM
mont-vol01 ONLINE 0 0 0
  mirror-0 ONLINE 0 0 0
    da4 ONLINE 0 0 0
    da1 ONLINE 0 0 0
  mirror-1 ONLINE 0 0 0
    da0 ONLINE 0 0 0
    da2 ONLINE 0 0 0
cache
  ada0 ONLINE 0 0 0

errors: No known data errors
[root@freenas /mnt]#

The reason I don't much trust RAIDZ (or Z2) is because it has crap for stability on really large pools. We are talking about 24 TB here, think about the chance for URE on 10^14 drives. Also wouldn't it end up taking 2-3 days to resilver the array if it failed due to the size? I don't want to have to endure an outage on my data for that long. I don't know, I'm not quite sold on Z2 either...

Anyways my original question was about a backup solution. My confusion came from the fact that it appeared the only 1 disk zvol you could create would be 'stripe' which sounds like RAID0. My concern is I didn't want to use a RAID0 stripe for a zfs backup volume. Is this a semantics misunderstanding or is there another option?