ZFS/FreeNAS question: Is 32GB of ECC RAM sufficient for 32TB of storage?

[billhickok]

I want to build a RAID Z2 array using ZFS and ECC RAM. I will be using 8 x 4TB hard drives and an Intel E3 quad-core processor. I plan on running FreeNAS. The thing is, these processors and the supported motherboards only supports up to 32GB max RAM. I've read that in such a setup running FreeNAS, it is highly recommended to allocate 4GB of RAM + 1 GB additional for each 1TB of storage. That means a minimum of 36GB is needed in my case.

My question is,

Can I get by with only 32GB of RAM for my 32TB of space? Besides storage, I only plan to utilize this NAS as a media server using Plex to transcode/stream 1 or 2 1080p rips.

I've read of a case where someone utilized 6 x 4 TB hd's (24TB total) and nearly maxed out all 32GB of RAM in his set-up, also running FreeNAS with ZFS Raid Z2.

Any input is appreciated.

 

[Captain_WD]

I want to build a RAID Z2 array using ZFS and ECC RAM. I will be using 8 x 4TB hard drives and an Intel E3 quad-core processor. I plan on running FreeNAS. The thing is, these processors and the supported motherboards only supports up to 32GB max RAM. I've read that in such a setup running FreeNAS, it is highly recommended to allocate 4GB of RAM + 1 GB additional for each 1TB of storage. That means a minimum of 36GB is needed in my case.

My question is,

Can I get by with only 32GB of RAM for my 32TB of space? Besides storage, I only plan to utilize this NAS as a media server using Plex to transcode/stream 1 or 2 1080p rips.

I've read of a case where someone utilized 6 x 4 TB hd's (24TB total) and nearly maxed out all 32GB of RAM in his set-up, also running FreeNAS with ZFS Raid Z2.

Any input is appreciated.

Hey there billhickok and welcome to Tom's Hardware Forum,

1GB for every TB should be just fine. I've read quite a good amount of feedback on this an I haven't seen people having trouble with not enough RAM if they use 1GB memory = 1TB of storage. I've seen people doing just fine with 4GB of memory on a 10TB array and after upgrading to 8GB - results were it worked like a charm. IMHO you should be just fine with 32GB.

You will be having a good CPU so streaming and multitasking shouldn't be an issue. If you want to reassure yourself, get a faster RAM sticks (1866MHz, etc.).

You can always contact the manufacturer and just ask for some advice.

Hope this helps,

Captain_WD.

 

[Ijack]

I'd agree that 32GB should be fine, with one proviso. Don't use deduplication. Great idea in theory but it is extremely memory hungry.

 

[Captain_WD]

True that for the deduplication. Even though it sounds great and secure, it would eat upa huge chunk of your RAM, especially with that huge storage. I believe 40Gb wouldn't cover it and still enable your system to run smoothly... IMHO it is not worth the extra investment in larger memory size (even upgrading the MOBO and PSU) for these features if you have such big-sized pool.

Captain_WD.