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mdgm

macrumors 68000
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Nov 2, 2010
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I was thinking of getting a Mac Pro for performance testing file transfers. To make it useful for a long while I was thinking it would be good to get one that could max out 10GbE (using a 10GbE PCIe card) with an array of SSDs.

However I've read that the Mac Pro can't handle a RAID-0 array that would give sufficient performance. Is this likely to be addressed anytime soon?
 

macz1

macrumors 6502
Oct 28, 2007
315
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I know there is a total speed limit for internal SATA drives due to the chipset, but I don't see why a PCIe card with externally attached drives should be slower on a Mac Pro than on other systems...
 

mdgm

macrumors 68000
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Oh, I was wanting to use SSDs internally and just get a PCIe card for 10GbE (the internal NICs in the Mac Pro really should be 10GbE but they're not).

So that's not possible?

Any recommendations for PCIe cards for 10GbE and for using SSDs such that you could saturate a 10GbE connection?
 

Transporteur

macrumors 68030
Nov 30, 2008
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Bearing in mind that 10GbE should be good for about 1.2GB/s, you'd need a proper RAID card and 5 SATAII SSD's in RAID0 to saturate this (uncached transfer).
With the upcoming SATA 6Gb/s Sandforce SSD's, three of them would already saturate this (500MB/s each).

Which ethernet card are you considering? I haven't found one that is supported by OS X, yet.
 

mdgm

macrumors 68000
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Nov 2, 2010
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O.K. Sounds like from this that I'm best to wait and see what next years Mac Pro models are like.

Hopefully next years model will have an easy way to support what I want.
 

cutterman

macrumors 6502
Apr 27, 2010
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deconstruct60

macrumors G5
Mar 10, 2009
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Oh, I was wanting to use SSDs internally and just get a PCIe card for 10GbE (the internal NICs in the Mac Pro really should be 10GbE but they're not).

So that's not possible?

Pragmatically no. Let's start with a diagram on the linked page below. ( the Mac Pro would have either a X58 or 5500 but makes no difference they play the same role with respect to the DMI bus interface. )

http://en.wikipedia.org/wiki/Intel_X58

The internal SATA controller is on the other side of the DMI (2GB/s) bus from any 10GbE PCI-e card you are going to get. The PCI-e card will be hooked to the x58/5500 chip. So they are separated by a 2Gbps link.

While each SATA link to the controller is 3Gbs there are no guarantees that the controller's link to the rest of the computer runs that fast. It never does (SATA isn't set up so that all of the links are active all the time). Typically they cap out around 2-3 links.

There is several of different sources of I/O for the shared DMI link : PCI-e v1 (firewire on Mac Pro) , 1GbE links, USB , etc. . It would be bad to let one of them oversaturate the link.


Any recommendations for PCIe cards for 10GbE and for using SSDs such that you could saturate a 10GbE connection?

This seems like yet another set up for selling PCI-e RAID cards in this forum, but ....

You have better chance if use two SATA controllers.

Two SSDs on the internal controller. And two SSDs in an external box on a 4x PCI-e v2.0 controller ( in one of the 4x slots ). It need not be a "proper RAID card". RAID-0 just means getting the data off the spindles. It isn't that hard nor that much overhead. The card needs to be just fast enough to pass through what the second SATA controller is pulling. Especially, since you're about to turn around and pump the data right back out the TCP/IP stack. The 10GbE card would go into the second 16x slot.

If you just want to blow off DMI link all together then a SATA II 4x PCI-e 2.0 RAID controller. The problem with the "real RAID" cards commonly thrown around here is that they are 8x and you don't have a 8x slot to put it into. ( you can go through gyrations to hook the cards to the internal drive sleds. )
If you find a 10GbE card that will work in a 4x slot, you may choke off the 10GbE throughput, but that's more likely because not getting data to/from the card.

You need a bit more than than the raw PCI-e link speed because there are various systems with overhead along the way from disk to os to tcp/ip stack to wire (and back. )
 
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goMac

Contributor
Apr 15, 2004
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What do you need to do with your computer? 10 GbE backbones are used to support massive infrastructures. The switches are $20k+:confused:

This.

Even 4 SSD's aren't going to saturate 10 gigabit. 10 gigabit is usually meant for backbone work where you have multiple servers all cramming their data onto one pipe (which is why I'm more confused you suggest that the Mac Pro is lacking for not including 10 gigabit.)

Best way to bench a 10 gigabit network from a machine? Simply write some code that opens a socket and streams bits out without hitting the drives. Probably the simplest way to do it. Or put a huge RAID box at the other end.

But, as mentioned above, 10 gigabit gear is very expensive.
 

mdgm

macrumors 68000
Original poster
Nov 2, 2010
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Was basically hoping to get a Mac Pro that would be good for performance testing for 5-10 years. I was thinking that being able to handle 10GbE using SSDs would've meant it'd be fit for purpose for that amount of time.

You can do a direct-connection for performance testing. No need to go out and get an expensive switch.
 

deconstruct60

macrumors G5
Mar 10, 2009
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Was basically hoping to get a Mac Pro that would be good for performance testing for 5-10 years.

performance testing of what if not really hitting a network ? Pulling pushing info through the box? Or or the card (when it doesn't have to deal with a switch.) ? Or the card in the other box ?
 

goMac

Contributor
Apr 15, 2004
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performance testing of what if not really hitting a network ? Pulling pushing info through the box? Or or the card (when it doesn't have to deal with a switch.) ? Or the card in the other box ?

Yeah, not sure what the point is. It would totally not be a real world benchmark.
 

dknightd

macrumors 6502
Mar 7, 2004
334
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Usually with network testing you try to pump data from memory at one end to memory at the other end - otherwise you are testing disk at each end rather than networking.
 

beaker7

Cancelled
Mar 16, 2009
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If you are waiting for 10Gb to become standard on any workstation, you are going to be waiting a very, very, long time.
 

mdgm

macrumors 68000
Original poster
Nov 2, 2010
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Was wanting to test transfers from disks from one machine to another.

If you are waiting for 10Gb to become standard on any workstation, you are going to be waiting a very, very, long time.

That's disappointing. Would've thought the Mac Pro should have it already considering the high price. I would've thought 10GbE would be more prevalent as GbE is a major bottleneck now.
 

beaker7

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Mar 16, 2009
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Would've thought the Mac Pro should have it already considering the high price. I would've thought 10GbE would be more prevalent as GbE is a major bottleneck now.

But why? Most corporate networks are still 100mbit. Only a few I've seen are even 1 Gb. Even modest 10GB switches are 20k. It'll be at least 10 years before you see it become close to standard.
 

dknightd

macrumors 6502
Mar 7, 2004
334
1
Was wanting to test transfers from disks from one machine to another.

What are you going to put at the other end?


That's disappointing. Would've thought the Mac Pro should have it already considering the high price. I would've thought 10GbE would be more prevalent as GbE is a major bottleneck now.

Give it a year or so, 10Gb will be more common. I'm not sure I understand the desire to purchase a machine today that will work for testing for years to come. If you are testing cutting edge you need to update more often than that.

edit: if you find a machine that costs about the same as a mac pro that can saturate 10GbE to/from disk, buy it, and please let us know what it is. Thanks
 
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dr. shdw

macrumors 6502a
Aug 27, 2008
964
0
But why? Most corporate networks are still 100mbit. Only a few I've seen are even 1 Gb. Even modest 10GB switches are 20k. It'll be at least 10 years before you see it become close to standard.

100mbit is the bane of my existence. Thankfully the place I work at now has 1gbit everywhere. Pushing stuff over the network with 100mbit is a pain.
 
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