Possible to replicate iSCSI device extent

[Haxim]

I'm curious if it's possible to replicate an iSCSI device extent to another FreeNAS box. I currently have an iSCSI device extent which houses some backups, but I'd like to also replicate that data offsite. From what I've read in http://doc.freenas.org/index.php/Replication_Tasks replication requires a periodic snapshot task, however it doesn't appear that my device extent is selectable as a filesystem/volume in periodic snapshot tasks. Is there some way I can accomplish this?

Thanks!

 

[cyberjock]

Is your iSCSI device on a UFS drive? Why do you say its not selectable?

 

[Haxim]

Is your iSCSI device on a UFS drive? Why do you say its not selectable?

Bear with me as I'm extremely new to FreeNAS :). As far as setup goes, I have 3 drives in a hardware RAID 5 being presented to FreeNAS as one logical volume. That one logical volume I set up as a device extent under the FreeNAS iSCSI settings and configured the iSCSI target settings to present it to my servers (3 ESXi hosts). If I go into "Periodic Snapshot Tasks" and attempt to add a periodic snapshot, the Filesystem/Volume dropdown box is empty (I assume it's because there aren't any filesystems/volumes, since I'm using a device extent?). If that's the case, if I were to use a file extent instead of a device one, would I be able to replicate that data to another FreeNAS server?

 

[cyberjock]

Are you using ZFS? snapshots are a feature of ZFS. If you are using ZFS you are in for serious pain later because ZFS should never be used on a hardware RAID. It's all over the manual, all over the forum, and mentioned in the noobie guide to FreeNAS(link in my sig). Even if you have an empty zpool you should be able to add a periodic snapshot, so I'm getting the impression you are either very very confused or aren't using ZFS.

Can you post the output of zpool status?

 

[Haxim]

How about very confused and not using zfs?

Code:

[root@nas01 ~]# zpool status                                                
no pools available

So basically the best course of action here is to forgo the hardware RAID, set up a zpool and then create an iSCSI file extent and then I can snapshot/replicate the extent file to the other NAS?

 

[cyberjock]

Yeah, you are using UFS(and confused by your own admission). That's why you can't do snapshots. Snapshots are part of the ZFS file system and not an "extra" feature that works with any file system.

Yes, you setup a zpool and then iSCSI with snapshots for backing up. But there are limitations to using iSCSI on ZFS. Because it is copy-on-write you can run into performance and reliability issues with the system using iscsi. Search the forums as there's a ticket(it's 1500-something) and read up on it. Some people have no problem at all while others can't keep iSCSI operating no matter what they do.