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

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

I don't think the 8 GByte version makes sense since Raspian is a 32 bit operating system.

Zitat von B3rnd

I don't think the 8 GByte version makes sense since Raspian is a 32 bit operating system.

since couple of years is raspberry using 64bit cpu and also their OS is 64bit operating system https://www.raspberrypi.org/pr…4-model-b/specifications/

Zitat von geaves

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

Zitat von geaves

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.

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

Zitat von ProteanEagle

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,

Zitat von macom

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"

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.

Zitat von ryecoaaron

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.

Zitat von ryecoaaron

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

Zitat

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,

Thank you for this. Finally cleared some doubts.

Zitat von ryecoaaron

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", )

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.