RAM requirements?

[JSS]

I set up my first FreeNAS system a couple of days ago. I used my old Dell Dimension 4600 for the install, and these are the basic machine specs:

Pentium 4 @ 3 gHz
2.5 GB RAM

I have FreeNAS 8 installed on an 8gb USB flash drive.

My goal is to use ZFS and have a zpool with a total size somewhere in the 10-12 TB range. My concern is the RAM requirements for FreeNAS 8.0. With the system I have, I could potentially max out at 4GB RAM, because that is the max that the motherboard will support (and it would be pointless to go over 4gb because it's a 32 bit system). But, I'd prefer not to spend money on more RAM if I didn't need to.

For my storage, once the zpool is set up, it'll have about 8 TB of data immediately. This data will not be edited or modified, just stored. The only changes will be to add new data. and after any new data is added, it too will not be editing or modified.

So, how is my system going to run with 2.5 GB of RAM? Will it function, just be slower? I don't need crazy fast performance or anything, as long as it's fast enough that I can play video files from the zpool without any hiccups (which is actually fairly low requirements - as long as it can do 2 MB/s transfer speeds, that should be more than enough).

Any thoughts?

Thanks,
Jason

 

[ohnename]

Just try it out.
I got it running with a simillar config (see my sig) with about 20MB/s CIFS (100Mbit/s=10-11MB/s, WLAN54= 1,5MB/s, WLAN300=10-15MB/s) so it is only too slow for Gbit/s LAN. Playing videos or music from the share is no problem.

 

[JSS]

thanks for your response.

While it's encouraging that you're running a system similar to mine with just 2gb RAM, my concern is that the total storage in my ZFS volume is going to be about 10 times the size of yours (somewhere in the 10-12 TB range to start). Is the additional storage in my ZFS volume going to require more space? Do you think it will still run OK?

 

[praecorloth]

(and it would be pointless to go over 4gb because it's a 32 bit system)

This is a hold over from the 32bit Windows days. Intel introduced PAE back in the days of the Pentium Pro, if memory serves. That allows you to address 64GB of memory on a 32bit system. Granted, there are certain performance hits you have to be willing to take. But that all could be a moot point anyways.

Hardware is pretty inexpensive these days. I've had good luck with 1.5 gig of memory to 500 gig of drive space. I have to believe that ZFS will scale memory usage nicely, so you won't necessarily need 20x the amount of memory that I'm using. Perhaps browse Newegg a bit and see if you can find a motherboard/processor in your price range that will support like 16-24GB of memory and then start out small with like 8GB installed and see if ZFS remains stable. If not, bump it up a few more gigs.

In the end it would be nice to have some hard numbers for disk space to memory ratio, but I haven't run across them yet.

 

[JSS]

Hardware is pretty inexpensive these days. I've had good luck with 1.5 gig of memory to 500 gig of drive space. I have to believe that ZFS will scale memory usage nicely, so you won't necessarily need 20x the amount of memory that I'm using. Perhaps browse Newegg a bit and see if you can find a motherboard/processor in your price range that will support like 16-24GB of memory and then start out small with like 8GB installed and see if ZFS remains stable. If not, bump it up a few more gigs.

well, my initial budget for this little project was $0, because I had an unused computer ready to go and I thought that it would fit the bill for this freenas.

My current system, with the 2.5gb RAM, crashed last night while copying files to the ZFS volume (currently @ 5TB, though as I mentioned above, I'm planning to grow it to ~10-12 TB). The error was RAM related, though I don't recall the exact error message right now. It wasn't just the zpool that went down, but I couldn't access the freenas server at all through the browser GUI. So I went down to the basement, powered it down, and then turned it back on again. Everything loaded up fine and it recognized the ZFS volume and all that - but I just don't know how stable it's going to be. I started copying more data to it this morning, we'll see if it's still up an running when I get home from work.

As I stated earlier, I don't need this to be a screaming fast machine - so if the 2.5gb of RAM is just going to cause things to go more slowly, that's fine. But if not enough RAM is going to cause stability issues, than I'll need to increase my hardware budget.

If I were to upgrade my hardware, at a bare minimum, I think I'd need a new motherboard, new processor (64 bit), and new RAM. and that's assuming that i can re-use the existing case, power supply, etc, etc...

I just did a quick look at some hardware at newegg. it looks like the bare minimum I'd be looking at ~ $220 (for an intel celeron E3400, an motherboard that supports 16gb of RAM, and 16 gb of RAM). but before I go buying new hardware, is there any way that I can get my current hardware to be stable with a ZFS volume ~10-12 TB?