64bit or 32bit for backup machine with 3gb?

[Oded]

Hi,
I now have my Freenas box up and running, and I want to turn my own Nas4FREE box into a backup appliance offsite.

The machine has a rather slow atom based processor that is 64bit, however the motherboard is limited to 3gb only, so that's the max.

For these specs, and for a 4x2tb box, would I be better off going with 64bit os or 32bit os? I know the docs say 4gb is minimum for 64bit, but that's for a machine that should be served on a daily basis, not a machine that just receives backups on a daily basis over a WAN connection.

Thanks.

 

[dlavigne]

If the processor supports it, ALWAYS go 64-bit.

 

[joeschmuck]

As Dru said, 64-bit if your CPU supports it and has no bearing on the RAM limitation, except that the 32-bit can only address the first approx 3GB or RAM in a system. Also the 64-bit version will be the only one supported in FreeNAS 9.3 and beyond.

Things to keep in mind...
The 8GB RAM minimum spec is a loose spec. Some systems can get by with 4GB while other must have 6GB. If you do run with 3GB and using ZFS your system could fail but you will have to test that out. Since you are migrating from NAS4Free to FreeNAS, recreate your pool to ensure you create the proper SWAP partition as this could be key in you system staying stable. And be aware that sometimes a GUI upgrade using such a low amount of RAM will fail. I have no idea why but I see the postings all the time. You may need to do an ISO upgrade for instance.

On your system do you actually have 4GB RAM? Also, do you have built in video, if so are you using shared RAM? If this is true then make sure you enter the BIOS and select the smallest amount of RAM you can to share with the video as this will free up some RAM for FreeNAS.

 

[Oded]

Thanks for the tips. Yes, I actually have 4Gb of ram, but only 3Gb is usable. Probably a motherboard limitation.
I will go into the BIOS and reduce the amount of video ram.
The reason I want to remain with ZFS is in order to use snapshots and replications over WAN to reduce the amount of data needed to be transferred. I wonder if RAIDZ1 will create a considerable bottleneck? I COULD go without any redundancy for the offsite backup... since I have a RAIDZ2 setup on my new machine.
Any tips regarding compression? other ways to keep the system as lean as possible without any throughput/servicing considerations (backup only)?

 

[Oded]

Huh. Freenas doesn't even let me use RaidZ1. only mirror or strip. Is that a RAM limitation?

 

[Oded]

Ok, it works when using manual setup.

 

[cyberjock]

Huh. Freenas doesn't even let me use RaidZ1. only mirror or strip. Is that a RAM limitation?

Not exactly. When you have <8GB of RAM people have weird unexplained behavior. Many people have complained that the volume manager excludes some options when you don't have enough RAM, but it's not coded to make some options unavailable. Your system just doesn't meet the minimum requirements so you can expect FreeNAS to behave erratically.

 

[joeschmuck]

Thanks for the tips. Yes, I actually have 4Gb of ram, but only 3Gb is usable. Probably a motherboard limitation.
I will go into the BIOS and reduce the amount of video ram.
The reason I want to remain with ZFS is in order to use snapshots and replications over WAN to reduce the amount of data needed to be transferred. I wonder if RAIDZ1 will create a considerable bottleneck? I COULD go without any redundancy for the offsite backup... since I have a RAIDZ2 setup on my new machine.
Any tips regarding compression? other ways to keep the system as lean as possible without any throughput/servicing considerations (backup only)?

The rest of your RAM I would expect to show up using a 64-bit OS minus the video usage. As for bottlenecks... You could have a bottleneck from the NIC if it's a Realtek just because you have a slow CPU, using ZFS in any way shape or form offers a potential bottleneck as well but has more to do with the slow CPU first and then RAM second, or it's a close tie.

My advice would be to use FreeNAS 8.3.2-Release (64-bit) and see how that works. It will be a bit more forgiving than the 9.x series of FreeNAS. If that fails to work for you due to a resources issue, roll back to 8.0.4-Release (I have a copy of it if you need it). It is the only one I know that would certainly be able to run given your resources, but 8.3.2 should be able to run fine too.

 

[Oded]

Currently it seems to run fine (with freenas 9).
I am able to perform two seperate dataset replications.
The one containing my data looks just fine, I can browse the files and see them there.

The one containing my Mac Time Machine backups is a different story. Seems to be "stuck'. doing an ls via ssh is stuck. Trying to use du -A -h to list the size of folders fails. However, I can see the ZFS dataset and size listed just fine in the web console.