FreeNAS on low RAM

[HussainJH]

Hi

I have an old PC that I installed FreeNAS on with intention of upgrading the RAM after I manage to install it. But after I installed FreeNAS I found out that the PC can only work with 4 GB RAM max. The minimum requirement for FreeNAS is 8 GB.
I've been using FreeNAS with 2 GB RAM only for about a month now and it works fine with no issue for my use.
My usage is very simple. One user & one HDD that I use to store Movies I download online so I can access them from my android TV.

Is there any risk if I keep using FreeNAs on 2 GB RAM or upgrading only to 4 GB ?

 

[jgreco]

Yup. You can keep on doing what you're doing, and if and when it decides to go sideways, please don't complain here.

Years ago, I raised the minimum memory required for FreeNAS and ZFS to 8GB. This was because there was a stream of reports in the forums from people with small-memory systems who set up their systems, had it appear to work, and then down the road at some point would suffer pool corruption and data loss.

It is possible that in the years since, whatever was causing the pool corruption has been fixed, but we really don't know, and no one has tried to study this in detail. It could be that you'll be just fine; the minimum has continued to be listed as 8GB because of various issues such as the size of the running OS image, and the basic ZFS ARC requirements for a modest system.

So, yes, there is significant risk, simply because we don't understand what used to (and might still) cause pool failures. If you're prepared to lose your data, then the flip side of the coin is lots of stuff has been fixed over the years, and ZFS should never actually do damage to a pool, so it is entirely plausible that this is no longer an actual problem. However, no one knows for sure.

 

[hescominsoon]

I go further and do not buld systems with anything less than 16 gigs of ram when it comes to zfs. 8 for the OS and then 8 minimum for the pool.

 

[Yorick]

One user & one HDD that I use to store Movies I download online

You may actually be better off with something that doesn’t use ZFS. ZFS trades its high hardware requirements for resilience; but your system is designed without resilience, and holds data that isn’t meant to survive.

That said, seeing how a low-mem TrueNAS system behaves and whether it will corrupt the pool could be a fun experiment.

 

[RKBock]

Yup. You can keep on doing what you're doing, and if and when it decides to go sideways, please don't complain here.

Years ago, I raised the minimum memory required for FreeNAS and ZFS to 8GB. This was because there was a stream of reports in the forums from people with small-memory systems who set up their systems, had it appear to work, and then down the road at some point would suffer pool corruption and data loss.

It is possible that in the years since, whatever was causing the pool corruption has been fixed, but we really don't know, and no one has tried to study this in detail. It could be that you'll be just fine; the minimum has continued to be listed as 8GB because of various issues such as the size of the running OS image, and the basic ZFS ARC requirements for a modest system.

So, yes, there is significant risk, simply because we don't understand what used to (and might still) cause pool failures. If you're prepared to lose your data, then the flip side of the coin is lots of stuff has been fixed over the years, and ZFS should never actually do damage to a pool, so it is entirely plausible that this is no longer an actual problem. However, no one knows for sure.

Atm, the corehardwareguide has 16GiB under minimum requirements. Is that correct? Would I likely encounter problems with just 8GB?

I'm planning to transform my old dust-gathering PC into a NAS for backups. Just a simple 2x4TB Raid1 storage that I'd access sporadically. The old PC, unfortunately, only has 2x4GB DDR3 memory. Would that be enough? Or do I need to to buy the 2x8GB DDR3 (old MB)?

Or would you say that FreeNAS isn't the system I should use?

Thank you in advance.

 

[jgreco]

the corehardwareguide has 16GiB under minimum requirements. Is that correct? Would I likely encounter problems with just 8GB?

Bearing in mind that I do not know for certain the reasoning behind the 16GB bump, I am nevertheless guessing that it has something to do with the addition of Gluster and containers and the peculiar way Linux handles ARC. It is now the year 2022 and there are cell phones with more than 16GB of RAM. It isn't particularly onerous.

That said, I don't expect that 8GB on a small system would be problematic. I haven't seen any reports that suggest it would be problematic. Just don't be stupid about it. No VM's, no jails (except perhaps very trite ones), simple usage. People inflict problems on themselves by thinking that they're magically exempt from requirements and guidelines.

On the other hand, 16GB of DDR3 is cheap. I bought 512GB of it for $800 so it can't be that much.

 

[RKBock]

Bearing in mind that I do not know for certain the reasoning behind the 16GB bump, I am nevertheless guessing that it has something to do with the addition of Gluster and containers and the peculiar way Linux handles ARC. It is now the year 2022 and there are cell phones with more than 16GB of RAM. It isn't particularly onerous.

That said, I don't expect that 8GB on a small system would be problematic. I haven't seen any reports that suggest it would be problematic. Just don't be stupid about it. No VM's, no jails (except perhaps very trite ones), simple usage. People inflict problems on themselves by thinking that they're magically exempt from requirements and guidelines.

On the other hand, 16GB of DDR3 is cheap. I bought 512GB of it for $800 so it can't be that much.

Thank you very much!
I, frankly, have no idea what Gluster, ARC or jails are and I don't plan on using any VM's on it either.

16GB DDR3 is "cheap" (55~80€), but I'm a student, and not really a wealthy one. Two 4TB NAS drives, one SSD and the bracket needed to mount the additional drives are already an investment for me. (though a necessary one as I'd like to backup my simulation results). I'd therefore like to avoid having to invest another ~70€ for RAM that probably won't even see much use. (I'll probably just upgrade to a bigger/better NAS once I have a job)