ZFS Format - Is it going to change

[joeschmuck]

Okay, this will be an odd question but since I don't know ZFS very well nor it's format I thought I'd ask this question...

Will the ZFS format which the hard drives are using in the most current version of FreeNAS, will it be compatible with future versions of FreeNAS or ZFS?

Also the Swap Space, is that also standard to ZFS? I have mine set at 1GB per drive vice the default of 2GB per drive. I was really thinking the Swap Space was FreeNAS specific.

I ask this odd question with one thing in mind, will my data be safe and work optimally when say FreeNAS 8.1 (or 8.2 really) final is deployed? And what about version 9.x whenever we see FreeBSD has a stable version of that.

I would assume ZFS is a standard and it is being adhered to so there would be no comparability issues in the future.

Anyway I'm getting to the point of formatting my drives for the last time and actually storing real data and not test data as it's looking like FreeNAS is about ready for use in my home to replace my aging slow NAS in the basement.

 

[pauldonovan]

The ZFS format is backwards compatible. Systems running newer versions of ZFS are able to read older versions. FreeNAS 8 is currently using ZFS pool version 15. FreeBSD 9.0 is/will using v28. A pool can be upgraded to the version that the newer system is running. Once it's upgraded it won't be readable by an older system.

At this stage ZFS versions are compatible between OS's, but I suppose it's possible that the FreeBSD ZFS code could go off on a tangent from the Oracle/Sun version. I'd be surprised though, as that doesn't help anyone.

The only current issue with your drives being portable is the way that FreeNAS sets up the partition table. It uses GPT, which Solaris can't read. So whilst Solaris could read the pool data, it can't find the pool data because it doesn't understand the way the disk is laid out. FreeNAS would have to use a different partitioning system for Solaris to read them. FreeBSD is able to do this, so FreeNAS would be in theory. However, it does appear possible to convert a GPT disk to the format Solaris wants without losing data, but I've not tried it. Here is the description: http://www.rodsbooks.com/gdisk/mbr2gpt.html

Paul

 

[joeschmuck]

Thanks Paul. That helps. I doubt FreeBSD would go off on a tangent as well, that would require too much effort to reinvent the wheel, and one that works at that.

 

[matthewowen01]

OpenZFS is great but if btrfs really takes off, we may see a decrease in priority to zfs but i'd doubt that.