Safe Conversion from FreeNAS?

  • Hello.


    I am a long time and current FreeNAS user. For many reasons, I am strongly considering a switch to OMV. But, I would like to do due diligence and have a solid transition plan before taking the leap.


    I am actually surprised that there aren't several "how to switch from freenas", "freenas vs omv" threads. Did I miss them (I searched)?


    I have already found partial answers to some of my questions in various threads. It is probably all in there somewhere. But, I feel that it would be helpful to a lot of people to consolidate this information within the context of my case (a user looking to switch from freenas to omv). So, I am hoping that the community can help out and fill in some of these blanks. Besides that, learning how helpful the community is is itself something I want to do.


    My Questions:

    • Is the hardware suitable for FreeNAS generally suitable for OMV? Or, are there key differences that a FreeNAS user should be aware of?
      I built a system for FreeNAS based on the best practices recommended for it. (ie. plenty of ECC Ram, a SuperMicro board, WD Red drives, etc.).
    • Is OMV more or less demanding of the hardware in terms of RAM, CPU requirements?
    • I see that there is a plug-in that allows running OMV from a USB. Does that mean that it can be run exclusively from USB, leaving the data storage completely untouched by the OS? Or, does it have to be installed onto the storage drives first and then set up with a plug-in that utilizes the USB?
    • Is there a guide that explains step-by-step how to install OMV onto USB? F
    • Assuming that OMV can run from USB, is there a way to have it run on a pair of mirrored USB drives like FreeNAS?
    • Are there any differences between the ZFS support in FreeNAS and OMV? In other words, could I install OMV to USB, boot it up next to my ZFS drives (set up with FreeNAS) and start using the same volumes, data, etc.?
    • Obviously, backing up key data first is important. But, are there any other safety precautions I can take to safely try out OMV with my FreeNAS-created ZFS drives? Or, once OMV works with those drives, will it prevent my current FreeNAS OS drives from working with them again?
    • It looks like there are both plugins and docker available for OMV. That seems to be over-lap of functionality to some degree. Is OMV moving toward a docker model and dropping plug-ins? What are the pros and cons (performance differences?) within the OMV context?
    • Has anyone else made this switch that can throw in 10 cents of wisdom/warnings? What has the relative experience been like? More or less CLI work? More or less stability, performance?
  • Is OMV more or less demanding of the hardware in terms of RAM, CPU requirements?

    New approach for Raspberry Pi OMV images -- any more questions? ;) It 'runs' even on hardware that is total junk from a 'NAS performance' point of view. On some more beefy ARM boards it shows similar performance than any Gigabit Ethernet bottlenecked x64 box but you should keep in mind that 'OMV' from a certain perspective can be considered 'just an UI' while FreeNAS automatically is associated with 'fully blown ZFS filer'.


    And that's the important thing: Once your feature set expands also hardware requirements increase. Sharing an ext4 filesystem of any size can be accomplished with almost every device that runs Linux while providing 100TB ZFS storage with compression and especially dedup is something completely different.


    Since you want to use ZFS you should carefully read through https://github.com/zfsonlinux/zfs/wiki/FAQ first. There are some architectural differences and as usual I would really take care about 'downgrading issues' (trying to import a zpool with higher version on a host that doesn't support the version). That being said I can't share switching experiences (since focussing with OMV on very lightweight / low energy devices currently), the big ZFS installations all run still on Solaris, FreeNAS or a commercial Linux based solution (Open-E).


    But I'm pretty excited about ZoL especially since version 0.7 able to use Intel's QuickAssist Technology (QAT) to accelerate various ZFS operations. Since OMV3 is based on Debian 'oldstable' it's pretty unlikely to get access to ZoL 0.7 anytime soon ;)

  • Hello.

    • Is the hardware suitable for FreeNAS generally suitable for OMV? YES.
    • Is OMV more or less demanding of the hardware in terms of RAM, CPU requirements? Less
    • I see that there is a plug-in that allows running OMV from a USB. Does that mean that it can be run exclusively from USB, leaving the data storage completely untouched by the OS? Or, does it have to be installed onto the storage drives first and then set up with a plug-in that utilizes the USB? OMV Recomend to install on a siingle HD (can be an old 2,5" SATA or IDE Disk, USB is not recomended , but is possible, the pluggin that you see is to reduce writes to USB and run in RAM as much as possible.
    • Is there a guide that explains step-by-step how to install OMV onto USB? YES, but is as easy as boot from ISO and install on desired drive. (Iso must be on a USB too to boot from it and dio the install).
    • Assuming that OMV can run from USB, is there a way to have it run on a pair of mirrored USB drives like FreeNAS?
    • Are there any differences between the ZFS support in FreeNAS and OMV? In other words, could I install OMV to USB, boot it up next to my ZFS drives (set up with FreeNAS) and start using the same volumes, data, etc.? You need to check it, I find some diferences in the past, but actually , I do not know, you can try from shell Zpool impot xxx like does in any other OS.
    • Obviously, backing up key data first is important. But, are there any other safety precautions I can take to safely try out OMV with my FreeNAS-created ZFS drives? Or, once OMV works with those drives, will it prevent my current FreeNAS OS drives from working with them again?
    • It looks like there are both plugins and docker available for OMV. That seems to be over-lap of functionality to some degree. Is OMV moving toward a docker model and dropping plug-ins? What are the pros and cons (performance differences?) within the OMV context?
    • Has anyone else made this switch that can throw in 10 cents of wisdom/warnings? I import sucesfully my Nas4Free ZFS pool but GUI in OMV was spartan so finally rool back to N4F (I have a working NAS whit ZFS pools on N4F and a working NAS with OMV for DNS, DHCP & Dowload). What has the relative experience been like? More or less CLI work? More or less stability, performance?
  • New approach for Raspberry Pi OMV images -- any more questions? ;) It 'runs' even on hardware that is total junk from a 'NAS performance' point of view. On some more beefy ARM boards it shows similar performance than any Gigabit Ethernet bottlenecked x64 box but you should keep in mind that 'OMV' from a certain perspective can be considered 'just an UI' while FreeNAS automatically is associated with 'fully blown ZFS filer'.
    And that's the important thing: Once your feature set expands also hardware requirements increase. Sharing an ext4 filesystem of any size can be accomplished with almost every device that runs Linux while providing 100TB ZFS storage with compression and especially dedup is something completely different.


    Since you want to use ZFS you should carefully read through https://github.com/zfsonlinux/zfs/wiki/FAQ first. There are some architectural differences and as usual I would really take care about 'downgrading issues' (trying to import a zpool with higher version on a host that doesn't support the version). That being said I can't share switching experiences (since focussing with OMV on very lightweight / low energy devices currently), the big ZFS installations all run still on Solaris, FreeNAS or a commercial Linux based solution (Open-E).


    But I'm pretty excited about ZoL especially since version 0.7 able to use Intel's QuickAssist Technology (QAT) to accelerate various ZFS operations. Since OMV3 is based on Debian 'oldstable' it's pretty unlikely to get access to ZoL 0.7 anytime soon ;)

    Thank you. Great information.


    Is the Pi build fully featured?


    I have a few of those around not doing anything. Is it possible to install OMV on a Pi to run plugins, docker, etc. but have it connect to shares on my FreeNAS machine for storage? Might be an interesting arrangement. Definitely a good way to test.


    Regarding ZFS, do you know which version is supported through OMV? I'm not running the newest ZFS version on FreeNAS. So, maybe there wouldn't be any downgrade issues.

    Thank you.


    I could install an HD just for OMV. But, seems like over-kill from a space/power usage perspective. What is the reason that USB is not recommended? Is it less stable? Slower?


    What about running the plug-in so that you boot from USB. But, it runs in RAM as much as possible?


    Are you able to access your ZFS NAS with your OMV NAS? If so, what is the process for that? That might be a best of both worlds solution.

  • Is the Pi build fully featured?

    Sure, the Raspberry Pi OMV image now uses only upstream Debian armhf repositories (so not compatible with single core Raspberries any more and only useable on RPi 2 or 3) but to be honest a Raspberry as OMV host is a joke since the Broadcom SoC on these boards is too limited (only a single USB2 connection to the outside where all 4 USB ports and Ethernet have to share bandwidth, both storage and IO performance sucks way too much).


    Raspberries are great for many use cases OMV not being amongst. But since we have +2000 downloads a week for these boards I thought it's worth the time to update/improve OMV on them. Wrt Docker: no idea whether the kernel we use (maintained by RPi people from raspberrypi.org) has all features enabled. It's 4.9.41 now so you should be able to google this :)


    Regarding ZFS, do you know which version is supported through OMV?

    The OMV philosophy is to use upstream Debian packages where possible so you get what's in jessie-backports repository (a 0.6.x). It seems that was different in the past and the zfs plugin used other package sources (see this example for update hassles that shouldn't happen). In other words: I'm not (yet) familiar with ZFS integration into OMV since my focus is currently on playing with a directly built ZoL 0.7 directly from Github repos.

  • What is the reason that USB is not recommended? Is it less stable? Slower?

    Neither/nor. People love to buy crappy flash products (counterfeit flash storage is still a huge problem) and these fail early. If you don't want to run Plex (or take care about Plex data location and symlink/move this to somewhere else) a 4GB boot drive is sufficient. If you want a flash drive storing 4 GB wearing out 16 times slower you simply buy a 64 GB thing and are done.


    The flashmemory plugin keeps all the stuff with a tendency for high write amplification in memory and saves it to disk only once an hour or on shutdown. So this also greatly reduces wear on flash media. There's nothing wrong using flash storage for the OS drive just try to avoid crappy USB thumb drives or SD cards, buy genuine products with larger capacity than needed, check them immediately with either F3 or H2testw, use flashmemory plugin and maybe disable monitoring and you're done.


    You might even be able to use RAID-1 for the OS drive but then you should try to use 2 different brands for this to make any sense. I would simply run 'dpkg --verify | egrep -v -i "/etc/|/boot/|cache|getty|" | awk -F" /" '{print "/"$2}'' from cron once a week since as soon as the first error appears here your OS drive needs a replacement.

  • Are you able to access your ZFS NAS with your OMV NAS? If so, what is the process for that? That might be a best of both worlds solution.

    Yes, I can mount ZFS shares on my OMV ( NFS Shares or SMB Shares of my ZFS pool can be mounted on OMV )

    • Offizieller Beitrag

    It looks like there are both plugins and docker available for OMV. That seems to be over-lap of functionality to some degree. Is OMV moving toward a docker model and dropping plug-ins? What are the pros and cons (performance differences?) within the OMV context?

    No, OMV is not moving toward a docker model or dropping plugins. It will continue to use both. docker runs at pretty much native speed. So, I don't think there are noticeable performance. Some people don't care for the complexity of docker (especially networking) or the ephemeral nature of docker. But some people like the ability to use newer libraries that the host OS doesn't have available or they just don't want to install many libraries that may affect stability of the host OS. I would say try both and use the one you like.

    omv 7.0-32 sandworm | 64 bit | 6.5 proxmox kernel

    plugins :: omvextrasorg 7.0 | kvm 7.0.9 | compose 7.0.9 | cputemp 7.0 | mergerfs 7.0.3


    omv-extras.org plugins source code and issue tracker - github


    Please try ctrl-shift-R and read this before posting a question.

    Please put your OMV system details in your signature.
    Please don't PM for support... Too many PMs!

  • my focus is currently on playing with a directly built ZoL 0.7 directly from Github repos.

    The part about ZoL has gone over my head. Is that different than ZFS? And, is it going to be implemented into OMV at some point?


    Sorry if that is a dumb question...

    Neither/nor. People love to buy crappy flash products (counterfeit flash storage is still a huge problem) and these fail early. If you don't want to run Plex (or take care about Plex data location and symlink/move this to somewhere else) a 4GB boot drive is sufficient. If you want a flash drive storing 4 GB wearing out 16 times slower you simply buy a 64 GB thing and are done.
    The flashmemory plugin keeps all the stuff with a tendency for high write amplification in memory and saves it to disk only once an hour or on shutdown. So this also greatly reduces wear on flash media. There's nothing wrong using flash storage for the OS drive just try to avoid crappy USB thumb drives or SD cards, buy genuine products with larger capacity than needed, check them immediately with either F3 or H2testw, use flashmemory plugin and maybe disable monitoring and you're done.


    You might even be able to use RAID-1 for the OS drive but then you should try to use 2 different brands for this to make any sense. I would simply run 'dpkg --verify | egrep -v -i "/etc/|/boot/|cache|getty|" | awk -F" /" '{print "/"$2}'' from cron once a week since as soon as the first error appears here your OS drive needs a replacement.

    Got it. Yes. I've had USB drives running FreeNAS go bad. But, it was easy to restore the OS from a config file that I was backing up automatically via cron.


    Does OMV use a config file like that? In other words, can I back up the OS config and quickly restore everything on a new drive/install if necessary by importing the config?


    Setting up RAID-1 on the USB drives manually is probably beyond my current capability. Or, is there an option for that in the install?

    Yes, I can mount ZFS shares on my OMV ( NFS Shares or SMB Shares of my ZFS pool can be mounted on OMV )

    Cool. I might try that to start. Do they have to be mounted with a manual process? Or, can that be done through the GUI? I don't recall seeing options for server-to-server share mounting within the FreeNAS GUI...

    No, OMV is not moving toward a docker model or dropping plugins. It will continue to use both. docker runs at pretty much native speed. So, I don't think there are noticeable performance. Some people don't care for the complexity of docker (especially networking) or the ephemeral nature of docker. But some people like the ability to use newer libraries that the host OS doesn't have available or they just don't want to install many libraries that may affect stability of the host OS. I would say try both and use the one you like.

    Thank you.


    I have used both in FreeNAS. Docker was briefly available in FreeNAS-Corral. Then they reverted back to a pre-Corral build (long story that you may already know). But, using docker for that brief time really opened my eyes to how much more the server could be doing. There are just so many cool/useful docker images now that are not reflected in the FreeNAS plugin list.


    So, I definitely want to use docker and am already familiar now with the environment variables, etc.

    • Offizieller Beitrag

    The part about ZoL has gone over my head. Is that different than ZFS?

    ZoL = ZFS on Linux

    omv 7.0-32 sandworm | 64 bit | 6.5 proxmox kernel

    plugins :: omvextrasorg 7.0 | kvm 7.0.9 | compose 7.0.9 | cputemp 7.0 | mergerfs 7.0.3


    omv-extras.org plugins source code and issue tracker - github


    Please try ctrl-shift-R and read this before posting a question.

    Please put your OMV system details in your signature.
    Please don't PM for support... Too many PMs!

  • Got it. Yes. I've had USB drives running FreeNAS go bad. But, it was easy to restore the OS from a config file that I was backing up automatically via cron.


    Does OMV use a config file like that? In other words, can I back up the OS config and quickly restore everything on a new drive/install if necessary by importing the config?

    No, OMV do not use a config file like FreeNAS or N4F to restore all your config, you need to do a new install and configure services by hand if O.S. Fails


    PD: You can do a clone ( using clonezilla or something simmilar), but as I say is not as easy as FreeNAS does).

  • Hi there, I've been using FreeNAS for a number of years on a home server running Plex and filesharing with 2 HDDs in RAID1. It's working fine now but I feel like I'm not really making the most of it.


    While I had time at the beginning to experiment with FreeNAS, I'm increasingly low on time and am looking to transition to a lower/easier maintenance option for when inevitably something goes wrong (better do it now than be forced to later when something goes wrong).


    Did OP follow through with this? Any lessons learned?

    • Offizieller Beitrag

    Hi there, I've been using FreeNAS for a number of years on a home server running Plex and filesharing with 2 HDDs in RAID1. It's working fine now but I feel like I'm not really making the most of it.


    While I had time at the beginning to experiment with FreeNAS, I'm increasingly low on time and am looking to transition to a lower/easier maintenance option for when inevitably something goes wrong (better do it now than be forced to later when something goes wrong).


    Did OP follow through with this? Any lessons learned?

    He only has 3 posts, so if he did he chose not to update anyone here about it.


    With such a simple system as yours... I think you'll find most recommend a simple rsync job to sync two drives, rather than raid1.


    If I were in your situation and it were possible, I'd back up my data to a 3rd drive, install OMV, format the storage drives to a more linux friendly file system (btrfs, ext4..) and then move your data back.

  • By way of update, I've successfully installed OMV5 (a struggle in it's own due to conflicting advice) and confirm I have successfully imported the zpools from FreeNAS 11.2 using the OMV ZFS plugin. I encountered a slight hitch/error with the import process using the webgui however this blog post showed me how to import it via ssh which was almost too easy.

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