OMV 5 on RPi4b SD card, moving from 2 GB RPi to 4/8 GB RPi

  • Hello. I run the OMV 5 for home use on my raspberry pi 4b, using SD card for root and 2x 4TB USB hooked up over USB hub for data. I use the 2 GB memory model of RPi without issues, everything runs just fine with no resource starvation. I plan to test around with additional plugins/modules like nextcloud, docker and so on. Think it would make sense to upgrade the RPi over to 4/8GB.

    Could I just plug the existing SD card with OMV OS to new RPi (same model, with upgraded RAM) connect the disks, and run it right off without reconfiguration? Thank you.

    RPi4b -> OMV 5 -> SD card root / 2x4TB WD Elements USB 3.0 -> External powered USB hub

  • hi, I think it should work like that, for sure make a backup image of the SD card.

    omv 5.6 in proxmox 6.3-6 - AMD Ryzen 1700 - 16GB DDR4 :thumbup:

  • since couple of years is raspberry using 64bit cpu and also their OS is 64bit operating system

    The 64bit raspberry os came out in May 2020 as beta there is nothing on raspberrypi.org to suggest this has changed

    Raid is not a backup! Would you go skydiving without a parachute?

  • Think it would make sense to upgrade the RPi over to 4/8GB.

    Create a clone/backup/image of the existing SD Card, install and deploy the additional Dockers you want to use and monitor it's performance you may find it's OK

    Raid is not a backup! Would you go skydiving without a parachute?

  • The 64bit raspberry os came out in May 2020 as beta there is nothing on raspberrypi.org to suggest this has changed

    RPi 3B+ has also 64bit CPU, and is old couple of years, so I tough they released also the 64bit raspbian with it, sorry for missleading info...


    if he used 64bit raspbian for his first install on the 2GB RAM RPi, i think it should work also on 4/8GB RAM RPi, but he should make an backup image to be sure

    omv 5.6 in proxmox 6.3-6 - AMD Ryzen 1700 - 16GB DDR4 :thumbup:

  • if he used 64bit raspbian for his first install on the 2GB RAM RPi

    I doubt that very much most users will go and grab the latest Raspbian Lite which is 32bit, while this will still work on an 8GB Pi you will only be able to access 4GB of memory

    Raid is not a backup! Would you go skydiving without a parachute?

  • I doubt that very much most users will go and grab the latest Raspbian Lite which is 32bit, while this will still work on an 8GB Pi you will only be able to access 4GB of memory


    Found this really good explanation about this (since I was also considering in upgrading my RPi to 8Gb).
    The topic is well worth the full reading.

    Backwards compatibility is a blessing, but also a curse: To maintain compatibility, the official Raspberry Pi OS is based on a 32-bit kernel. Normally, a 32-bit machine can’t access more than 4GB of RAM; in modern systems, physical address extensions (PAE) are used to unlock RAM above this limit - and it’s these extensions which allow Raspberry Pi OS to see the full 8GB on the latest Raspberry Pi 4.

    Source

  • Here is my system, I have two times 32 Bit. You only burn money if you buy the 8GByte version.

    Code
    pi@OMV2:~ $ inxi -Fz
    System: Host: OMV2 Kernel: 5.10.11-v7l+ armv7l bits: 32 Console: tty 0 Distro: Raspbian GNU/Linux 10 (buster)
    Machine: Type: ARM Device System: Raspberry Pi 4 Model B Rev 1.1 details: BCM2711 rev: b03111 serial: <filter>
    Argument "Raspberry Pi 4 Model B Rev 1.1" isn't numeric in sprintf at /usr/bin/inxi line 6969.
    CPU: Topology: Quad Core model: ARMv7 v7l variant: cortex-a72 bits: 32 type: MCP
    Speed: 1500 MHz min/max: 600/1500 MHz Core speeds (MHz): 1: 1500 2: 1500 3: 1500 4: 1500
  • Thanks I was thinking of 8GB model mainly to allocate the resources to docker containers thinking they will be able to make use of additional memory. I have overseen the 32 bit limitation.

    RPi4b -> OMV 5 -> SD card root / 2x4TB WD Elements USB 3.0 -> External powered USB hub

  • Thanks I was thinking of 8GB model mainly to allocate the resources to docker containers thinking they will be able to make use of additional memory. I have overseen the 32 bit limitation.

    You can go with the 8Gb board and use all resources, if you install a 64bit OS (been seeing several options non-Raspbian) and Ubuntu seems to be the one to use:


    https://certification.ubuntu.com/hardware/202004-27865


    https://ubuntu.com/raspberry-pi


    I think I'll go for it as I did the 4Gb: headless install, wireguard server, OMV, then docker with Nextcloud, SWAG, MariaDB and REDIS


    Issue is, before hand, make sure that all those apps/software runs aarch64/arm64, :)

  • OMV will not run on Ubuntu

    Bummer...


    In that case, will save the money, and keep with what's already working.

    "If it's not broken, don't fix it"


    8)


    But to stay on topic: even if the 32bit RPi "sees" all of the 8Gb RAM, does it take full advantage of it? Or will it be limited to 4Gb to a proccess?

    Just wonder to see if I can assign most of it to PHP for Nextcloud. (to raise the max_children available)


    On the 32Bit, 4Gb, I tried to set the "memory_limit=2048M" on Nextcloud ".../php_local.ini" and it always refuses.

    The max value it takes is 1536M.


    Thanks for any tips.

  • even if the 32bit RPi "sees" all of the 8Gb RAM, does it take full advantage of it? Or will it be limited to 4Gb to a proccess?

    It will be limited to 3GB per process.

    Just wonder to see if I can assign most of it to PHP for Nextcloud. (to raise the max_children available)

    If you are using more than 3GB per process on an RPi, that would be impressive.


    Thanks for any tips.

    Use the RPi 64 bit image. It has been very stable for me. Then you don't have these worries. https://downloads.raspberrypi.org/raspios_arm64/images/

    omv 5.6.13 usul | 64 bit | 5.11 proxmox kernel | omvextrasorg 5.6.2 | kvm plugin 5.1.6
    omv-extras.org plugins source code and issue tracker - github


    Please read this before posting a question.
    Please don't PM for support... Too many PMs!

  • If you are using more than 3GB per process on an RPi, that would be impressive.

    When I say that, I assume that is 3Gb total for the php master process (and then it's divided for the www pool, maybe I'm way off)

    But I can only push it to 1536M.


    Nonetheless, even with "only" 4Gb, it never starved for more.

    Use the RPi 64 bit image. It has been very stable for me. Then you don't have these worries.

    Isn't it still in BETA stage? And is it full 64Bit OS or just 64Bit Kernel with 32Bit libraries?!? (Let me quote something to see if I'm getting it right)

    Source

    Quote

    This should allow you to run 64-bit applications without LPAE limitation, but it’s still challenging since the Raspbian rootfs is still 32-bit only, so you’d have to build your own 64-bit libraries too.

    Main concern will be to know what version of the "apps" to use without hiccups (armhf or aarch)


    I have to make a test SD and see how it goes. Even if it's the same as the 4Gb, I can always use it to finally make a docker cluster with the RPis I've been hoarding, :whistling:

  • When I say that, I assume that is 3Gb total for the php master process (and then it's divided for the www pool, maybe I'm way off)

    3GB per process means each process can use 3GB. So, the php master process can use 3GB and each worker can use 3GB.


    Isn't it still in BETA stage?

    BETA according to RPi but the userland is real Debian 64bit arm64. So, really only the kernel is "beta" but I highly doubt there is much difference. It is just compiled at 64 bits. I have been using it a long time on a couple of RPi4s. I really hope you aren't running super important "production" on an RPi.


    Main concern will be to know what version of the "apps" to use without hiccups (armhf or aarch)

    What apps? It doesn't matter with php "apps". And you can run armhf and arm64 apps on arm64. So, what is the concern?



    omv 5.6.13 usul | 64 bit | 5.11 proxmox kernel | omvextrasorg 5.6.2 | kvm plugin 5.1.6
    omv-extras.org plugins source code and issue tracker - github


    Please read this before posting a question.
    Please don't PM for support... Too many PMs!

  • Thank you for this. Finally cleared some doubts.

    I really hope you aren't running super important "production" on an RPi.

    No, I don't work on IT, ;)


    This is just running a multi function server (wireguard, OMV, Nextcloud, Motioneye) for family private use and especially, to cut the ties with Google Photos and Drive, etc) and another one with LibreELEC.


    But I'm really curious and like to tinker with things, so am always testing other stuff. (next will be a cluster for "docker swarm", :D )

    Just need to get me some more RPis, hehe

  • I have 4GB version, but OMV5 with a light usage and SMB + NFS active uses 4% of memory. Currently 136MB used. Max used value was 165MB. A page cache occasionally goes up to 3.5GB (rsync or backup process), but usually stays at around 1.0-1.5GB, so 4GB is plenty for OMV use, unless you use it heavily.

  • This is just running a multi function server (wireguard, OMV, Nextcloud, Motioneye) for family private use and especially, to cut the ties with Google Photos and Drive, etc) and another one with LibreELEC.

    That is exactly my use case.

    I have 4GB version, but OMV5 with a light usage and SMB + NFS active uses 4% of memory. Currently 136MB used. Max used value was 165MB. A page cache occasionally goes up to 3.5GB (rsync or backup process), but usually stays at around 1.0-1.5GB, so 4GB is plenty for OMV use, unless you use it heavily.

    I am absolutely fine with this design on my 2 GB model. I am a bit concerned about running nextcloud on same box (docker/snap) due to database, webserver and other components ,not being much familiar with NC yet. I have another RPi4 running LibrELEC on 8 GB (I guess same overkill as with OMV due to 32 bit limitation). So anyhow, the initial thought was to swap SD cards between boxes to optimize the HW to the platform running on it. I am just thinking to complete the collection with 4 GB and use 8 GB for OMV+NC, 4GB LibreELEC and keep the 2 GB for testing or reserve.


    I also run ODroid N2 for my 4K HDR stuff. Its 64 bit CoreELEC and I recall this box can do OMV on armbian (AMLOGIC SOC), however all they come max with 4GB models so far.

    RPi4b -> OMV 5 -> SD card root / 2x4TB WD Elements USB 3.0 -> External powered USB hub

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