[build] Advise on low power RaidZ2 build

[bramv101]

Hi,

I have been digging around a bit and here are the things I already decided on.

1. NAS only works as file server and needs good data security,
2. no media server (this load will come on the shoulders of the htpc)
3. torrent/usenet downloading (rar/par should run during the night, so it does not interfere with other use of the NAS)
4. encryption? do i actually need this in a home environment?
5. location will be in the cellar, so can be noisy and cellar is always low temp
6. LOW power! The rest of my home has been built to be very ecofriendly, so i would like to keep all my electronics also low power.

I have decided on a 6 disk RaidZ2 setup with >= 16Gb RAM.
however I am still not clear on the CPU:
AMD vs intel?
Atom vs celeron vs Core?
Is the new Haswell going to be such an increase in power/performance?

thx for your advise

PS: any advise on a good case for this build?

 

[SleepySimon]

i think a new celeron got enough power for this job.

Intel Celeron G1610T (cheap)
Intel Core i3 3240T (more power)
both: 35W TDP

low power overkill: Intel Xeon E3-1220Lv2 17W TDP :D

 

[cyberjock]

My advice is don't even think about using encryption if you don't have a CPU with at least 4 cores(not threads) and has AES-NI support. The performance impact is significant even at that.

 

[abreis]

The best thing for low power and low noise is to use 2.5" drives instead of the normal 3.5". You'll pay a pretty penny for them though.
I just moved from 6*3.5" drives to 6*2.5". Power consumption dropped more than 20 watts from the drives alone, and they're much, much quieter. They seem to spin up and down faster as well, which is nice as I like to have FreeNAS aggressively put them to sleep.

Regarding hardware, well, the smaller the motherboard the better, and onboard graphics, of course.
Absolutely do go Intel. The above mentioned E3-1220L V2 is a terrific choice, if you can afford it.

Also remember that CPU TDP is not what your CPU is going to draw all the time — modern CPUs transition to low power states often. I have a 69W TDP Xeon here, and my *whole* server draws 40-50W idle (which is what it's doing most of the time).

 

[purduephotog]

Hi,

I have been digging around a bit and here are the things I already decided on.

1. NAS only works as file server and needs good data security,
2. no media server (this load will come on the shoulders of the htpc)
3. torrent/usenet downloading (rar/par should run during the night, so it does not interfere with other use of the NAS)
4. encryption? do i actually need this in a home environment?
5. location will be in the cellar, so can be noisy and cellar is always low temp
6. LOW power! The rest of my home has been built to be very ecofriendly, so i would like to keep all my electronics also low power.

I have decided on a 6 disk RaidZ2 setup with >= 16Gb RAM.
however I am still not clear on the CPU:
AMD vs intel?
Atom vs celeron vs Core?
Is the new Haswell going to be such an increase in power/performance?

thx for your advise

PS: any advise on a good case for this build?

I built a low power system utilizing 8x WD 2tb GREEN drives, an integrated celeron board (Biostar Intel NM70 Motherboard), and 8gb of DDR3 ram. I posted my power consumption results over at http://forums.freenas.org/threads/notes-on-performance-benchmarks-and-cache.981/page-3#post-49587

Power consumption for the system is listed there, as well as some standardized testing with the afore mentioned values, including 2gb, 8gb, and 16gb RAM on an identical platform.

Hope it helps.

 

[cheezehead]

Noisy generally equal low power...usually it means wasted power.

Really depends on what you are doing. Deduplication and gzip will increase the CPU and RAM requirements significantly. The 1GB per 1TB is a rule of thumb, not a requirement...depending on your usage patterns 4GB may just be fine, in terms of power consumption avoid using more than 2 sticks of RAM. CPU the lower the TDP the better. Basic file servers are just with Atom-based boards. Since your looking at 6-drives in particular I would look for a motherboard with 6xSATA ports onboard...an addon PCIE SATA/SAS card will add a chunk to the wattage.

For the immediate need now, I would agree with Simon on the G1610T for a general purpose file server. Right now I'm waiting, running an old desktop board (underclocked/undervolted) for the next few months waiting for some of the new AMD Kabini boards to come out which should be dirt cheap and extremely low APU TDP (sub-15w).

 

[jgreco]

The 1GB per 1TB is a rule of thumb, not a requirement...depending on your usage patterns 4GB may just be fine, in terms of power consumption avoid using more than 2 sticks of RAM.

4GB has not been fine for ZFS for some time, at least not without significant tuning. I recently bumped the 6GB ZFS minimum to 8GB for various reasons, specifically including that 6GB had proven to now be unstable under certain circumstances, probably due to increased memory pressures due to the larger FreeNAS image size combined with slightly higher requirements for v28. I haven't seen any reason to expect FreeNAS 9 would do better in this regard, so please understand when I come down kind of hard on 4GB. You won't be doing anyone any favors suggesting that this "may just be fine."

In 2005, memory prices were such that the difference between 6GB and 8GB would have been a major factor. Today, the price differential between 4GB and 8GB is very modest, and the choice should be between 8GB and 16GB. The only people who should be worrying about 4GB are those who are recycling systems that predate... maybe 2010?

So as to help make sure you don't take this the wrong way, I'll add that I have struggled with grasping this as well. I remember running 386BSD+the patchkit on a 386sx/16 with 2MB RAM, and when ZFS came out, I was quite horrified with the idea of a filesystem that really needed 1GB or more of RAM just to function correctly. I fondly remember the days of running a 68020-based Sun 3/60 with 12MB of RAM handling half a dozen interactive users, but the practical reality is that machines are bigger, storage is bigger, memory is bigger, and ZFS is able to do cool and amazing things when handed lots of resources.

4GB for UFS continues to be just fine though.

 

[cheezehead]

4GB has not been fine for ZFS for some time, at least not without significant tuning. I recently bumped the 6GB ZFS minimum to 8GB for various reasons, specifically including that 6GB had proven to now be unstable under certain circumstances, probably due to increased memory pressures due to the larger FreeNAS image size combined with slightly higher requirements for v28. I haven't seen any reason to expect FreeNAS 9 would do better in this regard, so please understand when I come down kind of hard on 4GB. You won't be doing anyone any favors suggesting that this "may just be fine."

In 2005, memory prices were such that the difference between 6GB and 8GB would have been a major factor. Today, the price differential between 4GB and 8GB is very modest, and the choice should be between 8GB and 16GB. The only people who should be worrying about 4GB are those who are recycling systems that predate... maybe 2010?

All depends on usage patterns and tuning. If it's data written once and then sits for years with barely being used (digital archive), then while functional is slow due to the limit ram. Above 4GB locks out most of the Atom-powered boards currently available.

Above 8GB the big issue I've seen has been underpowered processors (ie AMD's e350), in which case the Celeron 847 is a minimum and often I would look at a low powered i3.

ZFS is able to do cool and amazing things when handed lots of resources.

That's the real question, it all depends on which features are looking to be implemented. Deduplication, compression, scrub frequencies, amount of general usage on the system, types of usage (ie running 5 vm's off of or I need to be able to stream 4x1080P HD streams at the same time).

 

[jgreco]

All depends on usage patterns and tuning.

I'm going to criticize both points.

It no longer depends on "usage patterns". We've seen users with modest usage and 6GB systems that worked fine on FreeNAS 8.0.1 trainwreck on 8.3.

I agree that there is a dependency on tuning. Which is why I specifically had the RAM sizing document reference tuning. We do not expect 4GB to ever to be "just fine". It does not "depend" on "usage patterns" per your response that I was objecting to. It is certainly possible to tune a FreeNAS system to function acceptably on 4GB of RAM, but it is by no means the default, and those of us who spend time and energy assisting users in creating viable FreeNAS systems would kindly ask you not to imply that 4GB is acceptable without also adding that it will require significant tuning and potentially some future risk.

It is 2013. 8GB RAM is no longer a ton of RAM.

FWIW, most of the Atom boards out there suck for FreeNAS. Lack of ECC, 4GB soft or hard limit, and the inevitable sis, Realtek, or other craptacular Ethernet makes them poor choices. Supermicro makes a moderately respectable D525 Atom board, dual Intel gigE, 8GB RAM (works). Still no ECC, and rather pricey. Ugh.

 

[cheezehead]

Interesting, thanks for the info.

 

[cyberjock]

FWIW, I agree with jgreco. 4GB isn't really a "recommended" configuration. Noobs that are just starting out into the non-Windows world have virtually no chance of tuning ZFS enough to keep the system reliable. As we've seen from a few users, some people have had unmountable zpools from a kernel panic/improper shutdown.

Based on that information, I'd never recommend someone new to FreeNAS think they can "get by" with less than 8GB of RAM. Your zpool's health may be riding on your decision to use less.