ZFS with only 4GB ram

[bookie56]

Hi folks!
OK! I have a little dual core computer that needs a home and it already has a max of 4GB ram installed.

I wanted to install FreeNAS 8.2 on a USB and then use ZFS for my hard drives.
Can I manage with 4GB?

I am going to build a better computer at a later date...but just now I only have the 4GB ram to play with...

If the answer is no - what do you recommend?

I have drives formatted with ntfs and are quite full, but I hear ZFS is a supperior file system. Do you recommend ZFS on my setup?

Can Import ntfs drives or would that be defeating the object?

Thanks!

bookie56

 

[freeflow]

4GB is fine for a home server. Your data will be more protected and more transportable in ZFS. The hassle is getting the data from NTFS to ZFS.

 

[ProtoSD]

Yeah, 4GB is fine, it's what I use and it works great. 8.01 RC1 is supposed to have an NTFS volume import in the GUI, I haven't tested it, but that could reduce the hassle with moving data from NTFS. I did test the FAT volume import with a 2GB USB flash disk and it failed.

 

[callmedrdoom]

I am currently deciding whether or not to set up a FreeNas box, and although I have done my share of reading I am no expert.

I currently have 6 terabytes of NTFS formatted data, how difficult is it to move data from NTFS to ZFS/ could you point me to a resource on the subject?

Thanks

 

[bookie56]

Hi folks!
Thanks for the info.....
Much appreciated!

bookie56

 

[gcooper]

4GB is fine for a home server. Your data will be more protected and more transportable in ZFS. The hassle is getting the data from NTFS to ZFS.

Not necessarily true. We've seen high powered TrueNAS machines eat up more than 4GB of RAM with ZFS -- and there are machines I've seen that have eaten up more than 4GB of RAM with UFS. Given that a bunch of stuff runs in memory as well in /var, I would highly recommend getting more RAM and the requirements page has a fairly strict said set of guidelines on what you need in order to run FreeNAS: http://doc.freenas.org/index.php/Hardware_Requirements#RAM

 

[bookie56]

Hi gcooper!
Thanks for the update...I am putting this on hold until I can get hold of a new mobo...have a good processor and 6GB of corsair 1333MHz, but the motherboad is dead...

I will come back to this thread when I have had time to sort this out....

Thanks for all your input!

bookie56

 

[freeflow]

Oh good grief. For a HOME server 4GB is fine. Its unlikely you'll ever see any significant performance issues. I happily rand FreeNAS with a 8 drive ZFS2 array for over two years with 4GB ram and had no issues. If you operate outside the constraints of a Home server then more memory may give better results.

 

[Milhouse]

Oh good grief. For a HOME server 4GB is fine. Its unlikely you'll ever see any significant performance issues. I happily rand FreeNAS with a 8 drive ZFS2 array for over two years with 4GB ram and had no issues. If you operate outside the constraints of a Home server then more memory may give better results.

Agreed: I ran FreeNAS 0.7 on an N36L (AMD64) with RAIDZ1/4-disks and 2GB RAM for the best part of a year without any problems (even with prefetch enabled) - all it does is serve up the occasional media file. I eventually upgraded it to 4GB RAM when a disk died, but only because additional memory had become available from another project, not because it was required.

All in all, it really depends on what the server will be doing and how heavily loaded it will be. 4GB is a good middle-of-the-road recommendation, and more will usually be better but you can also scrape by on 2GB if the server isn't doing much. Not sure about 1GB though, now that could be a stretch.

 

[gcooper]

Agreed: I ran FreeNAS 0.7 on an N36L (AMD64) with RAIDZ1/4-disks and 2GB RAM for the best part of a year without any problems (even with prefetch enabled) - all it does is serve up the occasional media file. I eventually upgraded it to 4GB RAM when a disk died, but only because additional memory had become available from another project, not because it was required.

All in all, it really depends on what the server will be doing and how heavily loaded it will be. 4GB is a good middle-of-the-road recommendation, and more will usually be better but you can also scrape by on 2GB if the server isn't doing much. Not sure about 1GB though, now that could be a stretch.

You're assuming that we don't use memory disks for things in the system. Not entirely sure what setup FreeNAS 7 had (will dig up my VM remotely to verify), but depending on what you do with ZFS and your memory disks, what your network settings are, your NIC, etc, you can really tie the OS up in knots because of how memory is sliced up (hint: if you're digging into swap space, your machine is underpowered for what you're doing).

 

[Milhouse]

You're assuming that we don't use memory disks for things in the system. Not entirely sure what setup FreeNAS 7 had, but depending on what you do with ZFS and your memory disks, you can really tie the OS up in knots because ZFS is a memory hog, depending on the usage.

FreeNAS 7 used an embedded install, so everything ran from memory disk.

 

[s_mack]

Brand new to this... but would like to comment. Everything I see via Google for repurposing an OLD computer mentions a possibility is setting up a NAS and they almost all recommend FreeNAS. Then FreeNAS's docs pretty much say the system has to be > 4Gb to be anything but useless. > 4Gb = NEW computer, not OLD computer. 4Gb is a LOT of ram for a computer even just 5 years old. I've got a PC from 2003 and another from 2006 that I thought might be good candidates for this OS but one is maxed at 4Gb and the other has 4Gb with a limit of 8Gb, but frankly I don't want to spend $75 for more ram when the idea was to make use of an existing system.

I'm glad this thread was here because there are at least a couple of people confirming that 4Gb is sufficient, so thank you. I would suggest that the documentation watch its wording... it really reads like you shouldn't bother unless you go 64-bit, and you shouldn't bother with 64-bit unless you have > 4Gb ram. I thought Windows was supposed to be the memory hog??

 

[Durkatlon]

I think it's called C.Y.A. This way lack of memory can forever be blamed as the reason a particular install is not working. If you MUST have over 4GB of RAM, then there is not even a point in making available an i386 build. I have had Virtual Machines with 768MB of RAM run FreeNAS fine for months.

 

[s_mack]

But was it FreeNAS 8 that you ran?

 

[b1ghen]

I have been running Freenas 8 with a 6 disk (2TB) RAIDZ2 on a 4GB machine for about 6 months. For home use serving my HTPC and other PC's it has been working flawlessly. I usually get between 70-90 MB/s transfers with the crappy integrated Realtek 8111 NIC.

Sure this is a fairly powerful machine, AMD Athlon II X3 with the 4th core unlocked (used AMD to get ECC memory support), but I don't see the 4GB of RAM being an issue. I will be upgrading to 8GB or more soon though just for the sake of it :)

 

[Daisuke]

I think the easiest way to see if you need extra memory is by analyzing the swap usage. I run a ZFS RaidZ2 setup on 6 2TB drives (with a 7th SSD set as cache) with 4GB of RAM. The disk swap was never used, under the most extreme conditions. I performed stress tests on my NAS by randomly transfering data with short bursts as well very large files (4.5GB images). No issues what so ever. I'm not sure if the SSD disk set as cache helped in this situation.

Edit: I have to admit the 8GB memory and SSD cache upgrade I recently added to my setup drastically enhanced the overall performance:
http://forums.freenas.org/showthread.php?1310-My-new-NAS-box-running-on-8-0-2

 

[Brand]

I have been running a 10 x 2TB RAID-Z2 with 4GB DDR3 ECC RAM and a Xeon X3440 CPU since FreeNAS 8 was released and haven't noticed any major problems. The only thing that I am having issues with is the transfer speeds being slower than I would like even with two 1GB Ethernet ports aggregated together on the server, a switch that supports LACP and setup correctly, and two 1GB Ethernet ports aggregated together on a Mac Pro. Best practice for ZFS says to have at least 1GB RAM for every terabyte of storage so I just ordered 32GB DDR3 ECC RAM to replace what I have since I plan to add another 5 x 2TB or 5 x 3TB hard drives in the future. The RAM should be here on Friday so we will see if I see an improvement.

 

[gcooper]

The point that many people are noting here -- which is true -- is that ZFS likes RAM. RAM will speed things up because of how ZFS is designed, and invariably because RAM is much, much faster than any tertiary (spindles, SSD) storage out there. There are some that come close like Fusion I/O, STEC, Violin to name a few, but they're in the thousands of dollar price range -- and at that point I'm assuming that's outside most peoples' price ranges that are reading this forum right now.

In 8.0.3 memory usage has improved: the image size has shrunk ~20MB compressed, and a few other things have shrunk as well. That being said there's still a fair amount of stuff in the base system that can be pruned (I have a few patches I've been running on my system for a while that I could toss into the mix to save an additional 15MB-30MB, but they're based on 9.x+ sources).

After 8.2 more sane minimum limits are going to be imposed as needed to ensure that i386 is still an option -- to a certain degree because the more features you add, the greater your requirements will be, and there's a hard limit to what one can do with a 32-bit architecture, ZFS, and some of the features that are in FreeNAS (example: don't expect to be able to run AD/LDAP if you have less than 4GB of RAM without a large degree of tweaking of various rc scripts ;)..).

 

[zygoptera]

ZFS and 4GB

I am just a mere user without expert knowledge, but is it not the version of ZFS that gives the recommended minimum use of RAM?
As long as FreeNAS 0.7.x is used it is ok with 4GB but as we moved into 0.8.x the new recommendation is the 1GB RAM per TB of disk.

Ergo; would it not be recommended to NOT to use ZFS when setting up an older system with not so much RAM?

I am running 0.7.x with ZFS with 4 GB RAM/6 TB disk, and I am really happy with it. It is easy to set up, and I have had two disk crashes which was both so simple to replace that it is just silly.
I am still hesitant to experiment with FreeNAS 0.8 since it has less than the recommended RAM for this version, and there is no way back after upgrading.

 

[aaronb]

RAM necessary...

If you read across what has been posted, you are getting a consistent set of answers from different views:

I have been running FreeNAS 8.x (multiple versions) without problems on a dual-core system with 4GB of RAM. Swap file pretty much never used. It has 6 TBs of space.

So, yes, using ZFS on FreeNAS 8.x with 4GB of RAM is quite feasible.

Now, there are only a few machines in my house, and I'm pretty much the only person who uses the storage server, so high-performance is a relative concept for me. For me, this currently runs fast enough.

If you want higher performance from your FreeNAS box, then you really need to have more RAM. Recommendation is 1GB per TB of managed storage, with the minimum recommended being 8GB. This will bump the speed of your data transfers and generally make your NAS more responsive.

Further enhancements can be had by using Server-class NICs - lower overhead, better throughput. You can also use a SSD as a cache drive (ZFS manages what is on it automatically), which will bring further enhancements. Above that, you can bond NICs for better than GB throughput, but this takes switches that support it, as well.

So, if you want a high-performance NAS that will rival the high-cost ones ones from the major vendors, then you have to put a bit of money into this box and configure it well. If you want a decent storage platform running on your old hardware and can bear some performance penalties, use what you have lying around and understand 'it could be better'.

Want a good hint what you should get? Take a look at iXSystem's offerings for pre-built FreeNAS boxes. Know that they are built by the guys who know how to make them run good.