Recommended CPU

[kspare]

We're budgeting for our san upgrades in the spring and CPU's are on the priority list.

We have two sans, one has Dual E5 2620 and the other Dual E5 2603 V2

We had planned to use these systems with Starwind and so CPU's aren't a big priority on that software.

Fast forward and we have freenas running exactly how we want, but notice cpu usage can get high on backup days and causing some issues.

Both servers can use the same cpus. So is there a recommended CPU in the E5 family?

Our servers are used strictly for NFS VMware data stores.

We run 24 drives, PCie Slog, Pcie L2Arc. Currently 64gb of ram but thats next to get upgraded.

 

[jgreco]

The single E5-1650v3 is probably the hottest choice for a midrange NAS. Be sure to buy RDIMM, not LRDIMM, for it.

The E5-2643v3 is the obvious dual socket choice.

 

[kspare]

I've read in other posts that clock speed matters more than cores, the e5-2620 I have right now never really hits over 5% unless there is something major going on. Migrating machines onto storage from 10 hosts makes the server hit about 40% cpu with 600MB/s transfer speed.

Is a cpu like that really going to make a difference?

 

[jgreco]

I've read in other posts that clock speed matters more than cores, the e5-2620 I have right now never really hits over 5% unless there is something major going on. Migrating machines onto storage from 10 hosts makes the server hit about 40% cpu with 600MB/s transfer speed.

Is a cpu like that really going to make a difference?

5%... of what? A single core? Because if you're just looking at overall utilization, that's pretty useless. Of course it's mostly idle most of the time. In most cases, it *should* be.

The problem you posed was that you were pondering an upgrade, and what Xeons might be recommended. I *can* tell you that more cores are generally less useful than *fast* cores. I cannot tell you whether or not the fast cores would make a difference in your scenario.

The VM filer here has an E5-1650v3 in it. I can tell you that it doesn't need it. But at $550 for the CPU, it is the "you'll never need more than this" solution for that filer. Six cores, 3.5GHz with turbo to 3.8GHz, yeah, there's no doubt in my mind that we don't need the six cores. However, downsizing to the 1620 would mean a turbo clock of 3.6GHz, and less likely that the CPU would be in a position to go turbo. The 1620 wouldn't have been a *bad* choice. It's less costly for sure, but when you look at the incremental cost of bumping the CPU compared to the cost of the remainder of the platform (~$1000 in RAM for 128GB, ~$500-$1000 for a SLOG device, etc) the modest extra cash wasn't deemed a big deal just to "go all the way."

The big point that I'd make is that there's a MASSIVE price jump to go from E5-16xx to E5-26xx. The price differential is insane. The E5-2637v3 is almost $1000. 3.5GHz, quad core, similar in spec to a 1620 which is a third of the price. Of course, you're not deploying a 2637v3 by itself - you deploy two of them for octa-core goodness, but suddenly we're looking at a mainboard-plus-two-CPU cost of around $2500 for eight 3.5 GHz cores. Compare that to a 1650v3 plus mainboard cost of around $1000 for six 3.5 GHz cores.

So the 2637 is probably also a bad choice. If you REALLY need the dual CPU's, it's most likely for lanes, or for sheer memory, and you probably have a boatload of budget. In that case, there's still no real value in cheaping out on the CPU, and then the extra cores of the 2643 make sense in the same way that the 1650 is probably a better choice than the 1620.

 

[kspare]

you figured out my sticker shock lol.

Yes, generally it sits idle unless we do something major to create load, our other server has a 2603 and just doing replication it sits at 20% load, so it really needs an upgrade. but the other server with a 2620 sits at 5% doing replication.

However replication takes about 4 minutes.... so not a big deal there.

So justification for cpu taking a back seat to other things like memory.

I know I need memory and i've pretty much upgraded everything else to make my san's work properly.

Do I need a V3 cpu? if clock speed matters the most why not get a V2 or V1 cpu with a higher clock speed, they would be much cheaper?

 

[kspare]

Check out this comparison.
http://ark.intel.com/compare/83358,83354,83352,75792,75789,64598,64594

E5-2637V2 seems like it would be the ideal cpu? Even the V1 cpu is still pretty decent, with the new 2623 being close behind. for a budget the 2620 V2 and V3 isn't bad either?

 

[jgreco]

You're not likely to find the older gen CPU's all that much cheaper. You obviously have to figure out what makes sense for you to do; I was analyzing the question that you asked about "a recommended CPU in the E5 family." Especially including what I see as irrational pricing strategies.

Problems you could encounter: you might find yourself horribly broken if you try putting E5-16xx CPU's in a dual board. You might already have a legacy investment in LRDIMM that isn't compatible with E5-16xx. Etc.

A decent E5-16xxv3 2011 board is only ~$300 so it is very possible that it is a smarter idea to yank your existing boards and find a new purpose for them and then put in some X10SRL's with E5-1650v3 and 128GB RAM (~$2000 package deal). If you have any doubts about that recommendation, I should tell you that the last several systems we've bought here are X10SRW's with E5-1650v3 and 64 or 128GB of RAM and they're pretty awesome. Some are hypervisors, some are FreeNAS.

I think I can also fairly say that these systems would not be a downgrade. In the case of your dual 2620, that works out to about 20500 on geekbench, with an 1800 single core score, whereas the E5-1650v3 is around 20300 with a 3500 single core score.

From my perspective, I'm a cheapskate, so I find that staying in E5-16xx land is very attractive. I can stomach the E5-1650v3 double-the-price-for-50%-more-CPU thing but that's about the extent of my tolerance for B/S pricing.

 

[jgreco]

Check out this comparison.
http://ark.intel.com/compare/83358,83354,83352,75792,75789,64598,64594

E5-2637V2 seems like it would be the ideal cpu? Even the V1 cpu is still pretty decent, with the new 2623 being close behind. for a budget the 2620 V2 and V3 isn't bad either?

No. It makes no sense. You can go around replacing CPU and boards for the same-or-less-than the cost of the E5-26xx's.

E5-2637V2, if you could get it for $1000, to put a single CPU on a dual board? I can get you an X10SRL PLUS an E5-1650V3 for the same price (and you get two extra cores).

E5-2637V2, with two on a board, that's $2000, and okay, yes, you get more lanes and more slots for memory, but eight cores for $2000? I can get you an X10SRL PLUS an E5-1650V3 PLUS 128GB of DDR4 RDIMM for that same $2000. Yes, you're missing two cores, but we already established you probably don't need them.

Trying to upgrade E5-26xx based NAS systems is a game for chumps, as far as I can tell. Unless you are absolutely positively doing something where you NEED the lanes or NEED the slots for RAM, stick with the E5-16xx.

 

[kspare]

You are 10% right, checking ebay, new egg, ingram micro etc, there isn't much difference in price between generations, thats once you have sifted through all the engineering samples on ebay...

Your idea about swapping out the board/cpu is interesting idea. I'm going to look into this, our other san is used for file servers and one just for the terminal servers, upgrading one and putting the goods in the other would work well.

What about the 1630 cpu, it has a higher clock then the 1650 but both have the same turbo speed, while the 1630 has 10mb cache vs 15 on the 1650? I guess that brings up a new question, how important is the cpu cache?

 

[jgreco]

Yeh it all sucks amirite?

I believe I rejected the 1630 because while it has that higher clock speed, the reduced cache isn't great, and my best guess was that the 1650 would run similarly to it in the average case (turbo 3.8) but would have more cache, and in the event more CPU was needed, the 1650 has those extra two cores, even if it'll be running a tad slower while using them.

http://ark.intel.com/products/series/81064/Intel-Xeon-Processor-E5-1600-v3-Product-Family#@Server

There's also a few 8 core parts above the 1650, like the 1680v3. But when you start doing the math,

6 * 3.50 = 21.0GHz at $583 or $27.76/GHz

vs

8 * 3.20 = 25.6GHz at $1723 or $67.30/GHz.

If we extend that downward we also find

4 * 3.50 = 14.0GHz at $294 or $21/GHz
4 * 3.70 = 14.8GHz at $372 or $25.13/GHz

So you can probably see that the lower end of the 16xx's are more rationally coherent in terms of price per GHz.