FreeNAS in a Guest VM and file-level recovery: UFS or ZFS?

[dellock6]

Hi all,
I'm building a virtualized NAS for a customer, and since we need AFP access we decided to use FreeNAS thanks to its semplicity.
When configuring the storage, I have the choice of UFS or ZFS for configuring the underlying storage. In the Veeam Guide ZFS is only supported on Solaris Virtual Machines, while with FreeBSD (and FreeNAS is based on FreeBSD...) we have official support only for UFS and UFS2.

Does anyone have any experience with FreeNAS as a guest VM? I would say it's better to choose UFS over ZFS to guarantee compatibility with Veeam, but better double check before configuring all.

Thanks,
Luca.

[Gostev]

UFS would be preferred for file-level recovery, since we do not support ZFS versions following Oracle acquisition of SUN... these later versions of ZFS (beyond 23) are no longer open-source, so there are no Linux driver for the file system that we could use in our FLR appliance.

Here is a good reference of all ZFS versions:
http://en.wikipedia.org/wiki/ZFS#Comparisons

[dellock6]

Thanks Anton, I also checked the FreeNAS reference, in the last 8.3 they use ZFS version 28:

http://doc.freenas.org/index.php/Hardwa ... S_Overview

Seems from their docs that this is the latest open source version, but obviously it also depends on the corresponding drivers availability for your Linux appliance.

Thanks.

[markus.wild]

Hello,
we're currently evaluating replacing our agent based backup solution with veeam b&r. From what
I read in the documentation, current zfs filesystem is not supported for freebsd (but the used
illumos based zfs sources should also be available for linux, so I see no fundamental problem
in not supporting this filesystem in the flr appliance). Is this issue planned to be resolved in an
acceptable time frame? Or can we build a custom flr image somehow?
Kind regards,
Markus

[tsightler]

For filesystems not supported directly by the "Other OS" FLR, the easiest method for FLR is likely to be U-AIR since that method boots your entire FreeBSD instance in a virtual lab. You can then access the files from the production network and pull them out.

[danswartz]

Even though it's only a release candidate, ZFS on Linux is pretty stable nowadays...

[tsightler]

I agree that the latest native ZFS for Linux code is actually pretty stable, and should be interoperable with other community ZFS implementations (Illumos, FreeBSD) as well as older Solaris versions that use Zpool versions of v28 and prior, so maybe there's hope for FLR support in future versions of B&R for community ZFS versions, but not so much for newer commercial Solaris variants. U-AIR is always an option though.

[Gostev]

Any idea when ZFS on Linux is scheduled to be released?

[tsightler]

It will likely never be a part of the official kernel tree because of licensing compatibility issues, however, the current release is 0.6.1 and according to the release notes "Over two years of use by real users has convinced us ZoL is ready for wide scale deployment on everything from desktops to super computers."

https://groups.google.com/a/zfsonlinux. ... XADhyOwFfA
http://zfsonlinux.org/

[Gostev]

Ah, so the same licensing issues we have ran into...

[dellock6]

Well, ZFS belongs to Solaris, and Solaris belongs to Oracle, what would you expect from their licensing?

Luca.

[tsightler]

Yeah, probably the same license issue. ZFS is licensed under the CDDL, while the Linux kernel uses GPLv2. Unfortunately, while both of these are open source licenses, they are not fully compatible. In other words, it's not possible to ship a single linux kernel binary that includes both CDDL and GPLv2 code (or at least that's the prevailing opinion of the people that matter in making these decisions). It should be possible to ship the ZFS as a binary kernel module but I think our current ISO uses a statically built Linux kernel, probably for the sake of simplicity.

[dellock6]

Exactly. I've dealt in the past with CDDL license (OpenSolaris at that time) and reading through it, it does not sound so "open" as GPL. For sure is not possible to embed easily ZFS code into a linux kernel without some form of agreement with Solaris/Oracle, unless you use OpenSolaris itself instead of Linux as the underlying OS... Sadly because ZFS itself is a really great file system!

Luca.

[markus.wild]

Well, considering that zfs is here to stay, I see multiple options to resolve this:
- switch to using FreeBSD as the base OS for the FLR appliance
- use a zfs kernel module on the linux appliance
- provide a "flr-construction-appliance" that lets the customer perform the final linkage to generate a linux kernel veeam wouldn't be able to ship pre-built for licensing reasons. This is the same approach some companies use to generate windows-pe based recovery DVDs after Microsoft changed the windows-pe licensing
- publish complete sources for the FLR appliance so we can do whatever we need ourselves (actually, considering it's a linux distribution, where _ARE_ the sources?)

Cheers,
Markus

[Gostev]

Hi Markus, I will find out where those can be downloaded from, but I doubt the appliance sources will be of any use, because it is basic pretty minimalistic Linux without any modifications, just to provide the OS to run our code on. Most of the file restore logic is in the proprietary code that runs on top of the appliance. Thanks!

[UPDATE] The list of all open source components is linked in EULA, here is the direct link.
We can provide the source code for GPL components upon official request through our support.