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Raid0 SSDs in Mac Pro

Killerbob

Killerbob

macrumors 68000
Original poster
Jan 25, 2008
1,918
665
Hi,

I have the, wait for it... legendary 2008 Mac Pro, and a couple of years ago I installed an SSD from which I run OS, applications, and so forth. Now I'd like upgrade to two SSDs, and my question is;

If I install two Samsung 840 Pro SSDs, and run these in a Raid0 via the motherboard, would I see a performance difference? Is it the SSD or the interface that is the bottleneck?

/Bo
 
The SATA3 ports in your Mac Pro have a theoretical maximum throughput of 375MB/s, a bit less in real-world performance.

That means those ports will be bottlenecking the 840s. You might as well get two more affordable SSDs around the 350MB/s range. That would give you the same performance.
 
Did you patch the Kernel to suuport TRIM on your non apple-blessed SSD?

If not, I would double check the hardware via the OS to ensure that it's actually enabled. If it's not, I would gander that you could get a boost simply by fixing that on an old, well-used, SSD. (Also, you'll be needing to run at least 10.6.8.)


As far as I am aware, you are going to run into problems with the fact that the TRIM function won't yet work in a RAID configuration under OSX. If you want that variety of awesome, you'll have to switch over to mdraid on Linux.
 
JesterJJZ said:
I use Intel 320s in my 2006 and they are badass.
Click to expand...

I put two Intel 330s in my 2006 last week, and they fail to negotiate SATA 2 speeds reliably. Having them in a RAID0 means I get the same speed as a 2010 MacBook Pro with just one of them (260MB/s read, 230MB/s write). Still fantastic, but I might have just purchased SATA2 SSDs had I known ahead of time (Google was useless until I added 'negotiated port speed' to a search for Intel 330 & Mac Pro 1,1).

I imagine they'll scream when I put them in a machine with SATA 3 ports.
 
@ flatfoot - why is it only 375MB/s in the Mac Pro (early 2008), when the System Info says the interface is 3 Gigabit?

@ yergi - thanks for the heads up on the TRIM functionality on Raid0s. I use Trim Enabler" for TRIM on the Crucial C300 I currently use.

@ CaptainChunk - very cool. Do you know of anyone who have used that in a Mac Pro? And, will I still have the TRIM issue that yergi mentions?
 
Because 8 bits = 1 byte.

Also if you want to use RAID you won't get trim on anything but the latest Intel controllers (which you don't have).
 
@ CaptainChunk - very cool. Do you know of anyone who have used that in a Mac Pro? And, will I still have the TRIM issue that yergi mentions?
Click to expand...

I'm fairly certain that Yergi would be correct, as far as TRIM is concerned. (not supported under OS X in RAID configurations) And yes, you have to patch the kernel to get TRIM working on non-Apple OEM'd SSDs (non-RAID).

Another thing to consider is getting the single-drive version of Sonnet's Tempo SSD and throwing either a Samsung 830 or 840 Pro on it. Both drives are spec'd at over 500MB/sec reads on the 256/512GB versions without RAID. The 840 Pro does have faster write speeds, but I personally don't think it's worth the $70-80 price premium (256GB version) over the 830 right now.
 
OK, understand the comment about the 3 Gigabit now.

Checked out the technical details of the Sonnet Tempo SSD Card though, and "Currently no boot support for Mac Pro" means that's a no-go!

So, back to the drawing board.

What about 2xSamsung 840 Pros, via a Raid card? And in that case, what's a good Raid0 card, which supports 6GB/s, Raid0, and boots in OSX?
 
Apricorn Velocity X2 or Rocket 640l both are 4x SATA 3 and support bootable RAID 0 in OSX.

You'll discover after some research that the limit with a RAID 0 setup is the 4x speed of the cards, if you can, buy an 8x sata 3 card and your bandwidth result will utilise the full speed of two SSD's.

As for that 'Tempo Pro' thing, yeah it is nice having two SSD's on the card but the Velocity X2 supports booting, is just as fast, supports two SSD's and... it's a fraction of the cost!
 
That Apricorn Velocity X2 card is really cool! It doesn't say anywhere that it supports Raid0 though. Can you confirm that is the case? Also, it seems not every MacPro3,1 user has had luck with the booting off that card.
 
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Killerbob said:
That Apricorn Velocity X2 card is really cool! It doesn't say anywhere that it supports Raid0 though. Can you confirm that is the case? Also, it seems not every MacPro3,1 user has had luck with the booting off that card.
Click to expand...

I initially had trouble booting with the Velocity X2 card in my 2008 Mac Pro 3,1, but I finally determined that there was a conflict between it and a dual port eSATA card that I used to drive my external RAID-5 backup system. Removing the eSATA card resolved the problem and I can boot from the Velocity X2 with a Crucial M4 512GB SSD on board. I can use the second SATA port, routed to a back panel header, to drive the external backup drive system.

I am currently also evaluating a pair of 240GB OWC SSD drives in RAID-0 located in the optical bay and running off of the 2 motherboard SATA ports. It is working very well and provides higher write speeds, but slightly lower read speeds compared to the M4 on the PCIe X2 card. Booting is slightly faster with the RAID SSD due to the delay in recognizing the SSD on the PCIe card which is considered an external drive.

The RAIDed SATA-II drives almost completely offset the lack of SATA-III in the Mac Pro without adding an additional PCIe card.

There is a thread here where someone was making a RAID-0 using the Velocity X2 card. As I recall, they ran into bus saturation putting both drives on the same X2 card, but achieved phenomenal results when they used dual X2 cards with one SSD on each card. Unfortunately, the 2008 Mac Pro can't do that since there is only one available PCIe-2 high speed slot, whereas the 2009 and newer models have all high speed slots.


-howard
 
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OK, so a freiend of mine got me moving in the OCZ RevoDrive 3 X2 960GB card, which is priced like two Samsung SSDs and an interface card. It looks faster, but now comes the 1 million dollar question;

Will it work in my MacPro3,1 as a boot device?

/Bo
 
I did check out the Accelsior cards, and the price difference isn't bad, actually very comparable to the OCZ cards, but they are not as fast, and they also have some issues with booting in OSX. Supposedly the volume you create on an Accelsior card will not show up in the OSX boot menu.

But, I have found that the OCZ RevoDrive is NOT OSX compatible - sucks!

/Bo
 
FWIW, I just migrated from 3 OWC ssd's in raid 0 off an Areca 1880 controller to a single crucial m4 drive. Honestly the performance difference for a boot drive is not that different. The sustained transfer speeds will not scale accordingly as it is mostly random access.
 
Killerbob said:
Supposedly the volume you create on an Accelsior card will not show up in the OSX boot menu.

/Bo
Click to expand...

Is this confirmed in 10.6.8 and up? Or just with 10.8.2? I'm wanting to install the accessior PCI-E and run a 240 SSD in the lower optical bay while using three 2TB hdds. I wanted to boot from the pci-e. Anyone?
 
CaptainChunk said:
I'm fairly certain that Yergi would be correct, as far as TRIM is concerned. (not supported under OS X in RAID configurations) And yes, you have to patch the kernel to get TRIM working on non-Apple OEM'd SSDs (non-RAID).

TRIM is supported in SoftRAID on RAID 0 volumes running on Mac OS X 10.6.8 and later. SoftRAID will also patch the appropriate system files so you can enable TRIM with non-Apple branded SSDs.

You can get a 30 day demo from our web site.

Tim Standing
www.softraid.com
Click to expand...
 
That Apricorn Velocity X2 card is really cool! It doesn't say anywhere that it supports Raid0 though. Can you confirm that is the case? Also, it seems not every MacPro3,1 user has had luck with the booting off that card.
Click to expand...

I almost forgot about these cards! I suppose the only drawback would be that running a pair of them would eat up two PCIe slots.

But I must ask, is there a particular reason why you need SATA-6G SSDs in RAID-0 for your boot volume? A Samsung 830 256/512 on a 6G controller is already pretty darned fast (light years faster than anything you could achieve on a mechanical drive). I'm booting on an 830/256 right right now (only in 3G mode, however) and even with the 3G bottleneck, it's already about 2.5x faster than my Caviar Black was.

Your only other real option outside of what's already been mentioned is a bootable 6Gbps hardware RAID card (ATTO and Areca are good bets). And if you wanted to keep everything internal, you'd either have to install the SSDs in the second optical drive bay (several manufacturers make adapters for this) or buy special drive sleds that bypass the internal backplane (I don't think that the backplane connectors will support SATA-6G through an iPass cable, but I could be wrong).
 
I currently am using a Crucial C300 for my boot drive, and it is fast, and it works. However, I would like to expand, and use my C300 for Windows in Bootcamp only, and then find another (faster) solution for Boot/OSX/Applications.

So I see the new Samsung 840 Pros, and think, I'll buy two of these, and put them in Raid0, to get more speed and more space. However, the interface in my Mac Pro 3,1 are "only" 3GigaBit, and hence they will not fully utilise the SSDs. This leads me to the PCIe interface cards, for SSDs, or as "onboard SSDs".
 
Just go with single 840 Pro, it has enough performance and no need for a RAID setup which cause hassle.
The most important performance of any SSD is IO performance which is always below SATA 3 GBit/s limit, on desktop use.
 
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