Newb alert: Volumes, disks, pools, datasets... so confused

[csh8428]

So as you can tell, I'm a complete newb. I have a box that is more than capable of running FreeNAS. My purpose for it is for a Plex streamer and as a backup for data I have stored in other places, so I don't need any type of RAID mirroring. I also have 4 physical disks of 3 different capacities. Coming from Windows, I'm having a hard time understanding the differences between all the storage terminology. I already have an old install of FreeNAS 9.3 which I didn't use any volumes, datasets, etc, I only imported the disks and that's it. I don't have any other features going. It's simply a backup solution for data and a plex streamer. I want to do a clean install and do it right this time. However, I do NOT want to lose any of the data on the disks by accidentally doing something wrong.

Can anybody explain or point me to some good documentation that provides a bit of an analogy coming from Windows and/or explain what I can/cannot do to ensure I don't lose any data?

EDIT: I have read a bunch of documentation and it appears that volumes and datatsets had to be created manually, but after looking at my box I can see that volumes and data sets are created automatically when I import the disks and jail datasets are created automatically when I create the jail storage. I'm still having trouble understanding the physicall definitions of these terms though and how to relate them to the windows file system terminology.

Thanks,

Craig

 

[Robert Trevellyan]

I'm still having trouble understanding the physicall definitions of these terms though and how to relate them to the windows file system terminology.

Part of the challenge is there is no direct 1:1 correspondence, because ZFS is quite different from NTFS. Another issue is that the FreeNAS GUI and documentation use terms that differ from the terms used in ZFS documentation. For example, FreeNAS uses the term "Volume" where ZFS uses "Pool".

In ZFS:
total system storage consists of one or more pools
pools are made of vdevs
vdevs are made of physical disks or partitions of physical disks
redundancy (RAIDZ1, RAIDZ2, mirror etc), if employed, is present at the vdev level

Further, datasets are filesystems that can be created to manage the storage in a pool. Many filesystem properties are per-dataset, which offers great flexibility.

explain what I can/cannot do to ensure I don't lose any data?

Regardless of filesystem, having a proper backup strategy is the best defense against loss of data. Within a ZFS filesystem, having redundancy at the vdev level reduces the chances of data loss due to hardware failure, but does not prevent data loss due to user error. Having a sensible snapshot schedule can help with the latter, but cannot completely prevent it.