Mac Pro 5.1 SSD question : RevoDrive 3 or Crucial in RAID 0 for storage?

[bendinger]

Hi,

I need some advice to choose between Revodrive 3 X2 and RAID 0.

For scientific calculations I read/write and sort large (10GB+) files. We had multiple clusters at the university, but the disk speeds are serious bottlenecks (once I had a chance to test my stuffs on our storage rack natively (a base 4 core nehalem server with 24xHDD RAID and 96 GB) and despite the 0.5x cpu power (same cpu, only dual) it was much faster than the 2x4 core servers I use every day (4xHDD in RAID and 96GB), because of the read and write speeds (the computational part was of course slower)).

I have a base Quad Mac Pro 2010 which is a very good machine indeed. I decided to change my previous ssd (Intel x25-m G2 120 GB) and put it into my Thinkpad X60 (only sata I so the max. 100 MB/sec write speed is not a big problem). To replace it I am thinking about to get a pci-ex Revodrive 3 X2 240 GB to store my work data (~180 GB) and get a 128 GB Crucial M4 as a boot drive (plan A ). I read about the Revodrive's booting problems but I do not need it for booting, only as a very fast storage (for backup/videos/music I use the supplied WD Black). Can anybody confirm that the Revodrive 3 is working in Mac Os X as a storage drive? Right now I use Snow Leo but in the near future I will change to Lion (new OpenCL

The plan B is buying 2xCrucial M4 256 GB and run them in RAID 0 as a boot drive. But since the Mac Pro has only sata II ports the achievable maximal write and read speeds are 500-525/420 MBs against the Revodrive's 900/1000 MBs .

I really do not want to use HDD-s anymore only storing videos/music/backup (I used an 4200rpm drive for four years in my old toshiba laptop.... )) With a fast SSD solution I can finally use my Mac as a working machine (with the revo and a 6-core cpu it would be better for my needs as the octo at the uni )

Thank you!

 

[Hellhammer]

At least OCZ claims that it's only compatible with Windows. This thread indicates that there are several issues with the RevoDrive 3 under OS X, which isn't surprising since it's not officially supported. As you are buying it for work, I would not buy one. To be honest, I wouldn't buy OCZ in the first place.

There are SATA 6Gb/s PCIe cards that should enable 6Gb/s speeds. That way the Crucial M4 would be quite fast.

 

[Pressure]

According to OCZ it doesn't work in Mac OS X.

Why don't you grab something along the lines of the Norco DS-12D with room for 12 hard drives?

Download macZFS and make a large storage pool with the aided benefit of the ZFS+ filesystem for system integrity and error correction.

It will be fast and cheap.

 

[nanofrog]

There aren't any PCIe Flash Drives supported under OS X (promises have been made, but not delivered on).

Also note that the SATA ports (ICH) on your system will throttle at ~660MB/s, regardless of the number of disks (and software RAIDed SSD's don't do that well either, meaning what you'd expect isn't delivered from those that have tested multiple SSD's on the ICH in a stripe set).

So your best bet (particularly if you're after 1GB/s+), is to get a good 6.0Gb/s RAID card (ATTO or Areca), and setup an array built from SSD's off of that (bypasses the ICH for additional bandwidth).

MLC would be fine for a stripe set (0/1/10), but if you decide you might want a parity based level, you'd be better off going with SLC based disks as they can take the abuse (much higher write cycles than MLC; at least an order of magnitude). The reason, is most NAND suppliers offer 10k write cycles for MLC (some of the less expensive MLC is only rated for 3k - 5k writes, while SLC is 100k). These are minimum values, but it's what they can guarantee that it will handle (SSD makers tend to toss out the worst 10% in their statistical analysis).

Your other option might be SAS disks on a RAID controller. Either way, you're looking at a RAID card (use the PCIe bus to get around the ICH throughput limit for SATA), and rather expensive disks compared to 7200rpm SATA units.

I wish you luck.

 

[philipma1957]

why not do two upgrades buy a hex core cpu and do my cpu update cost is not bad. then strip a pair of samsung 470 sata II ssds put them in your empty bays. your cpu would gain 50% or so in speed and the samsungs in a raid 2 would pull 450mb/s read and write. some links

https://forums.macrumors.com/threads/1122551/


http://www.ebay.com/itm/Intel-Xeon-...725?pt=CPUs&hash=item3cbbabd29d#ht_2552wt_868

http://www.ebay.com/itm/NEW-Intel-X...57?pt=CPUs&hash=item2312528b49#ht_3265wt_1250


http://www.ebay.com/itm/Samsung-MZ-...ltDomain_0&hash=item4cf9a8bd9c#ht_1505wt_1111

 

[Pressure]

why not do two upgrades buy a hex core cpu and do my cpu update cost is not bad. then strip a pair of samsung 470 sata II ssds put them in your empty bays. your cpu would gain 50% or so in speed and the samsungs in a raid 2 would pull 450mb/s read and write. some links

https://forums.macrumors.com/threads/1122551/


http://www.ebay.com/itm/Intel-Xeon-...725?pt=CPUs&hash=item3cbbabd29d#ht_2552wt_868

http://www.ebay.com/itm/NEW-Intel-X...57?pt=CPUs&hash=item2312528b49#ht_3265wt_1250


http://www.ebay.com/itm/Samsung-MZ-...ltDomain_0&hash=item4cf9a8bd9c#ht_1505wt_1111

The problem with the Samsung 470 is that they have the worst write amplification of any of the current Solid State Disks. Stay clear of that one!

 

[porthosmac]

So your best bet (particularly if you're after 1GB/s+), is to get a good 6.0Gb/s RAID card (ATTO or Areca), and setup an array built from SSD's off of that (bypasses the ICH for additional bandwidth).

I have had a lot of problem trying to build a stable SAS external enclosure with SSD. When i saw the work of Rob at Barefeats, i bought a Stardom ST8 SAS with four Vertex 3 SSD (were cheaper than OWC). I could not format HFS+ the SSD array, even JBOD. I tried a RocketRaid 2744 and also Atto R680. No success. I downgraded to 10.6.7 from Lion. No success.
Now i finally gave up, put the four SSD in the internal bays (around 550 MB/s read and write) and put the WD disks in the enclosure. So, after shelling a lot of $$, i could not achieved the 1.5GB/s with the enclosure. SO, if anybody have a bunch of Vertex 3 working fine in a ST8, i would like to know how they did that.

 

[Hellhammer]

The reason, is most NAND suppliers offer 10k write cycles for MLC (some of the less expensive MLC is only rated for 3k - 5k writes, while SLC is 100k). These are minimum values, but it's what they can guarantee that it will handle (SSD makers tend to toss out the worst 10% in their statistical analysis).

Pretty much all current SSDs use 2Xnm flash which is rated for 3000 P/E cycles. 3Xnm can still be found in some older models but 5Xnm is pretty much dead and would cost a fortune anyway if you found one.

HET-MLC is the new thing though. Cheaper than SLC (as it's still Multi-Cell), yet much better endurance than regular MLC, although it's still way behind SLC and also slightly behind 50nm MLC. Intel is set to release 710 Series later this year with HET-MLC, might be worth waiting if SLC is out of budget.

The problem with the Samsung 470 is that they have the worst write amplification of any of the current Solid State Disks. Stay clear of that one!

I guess that is what you get from aggressive garbage collection.

 

[nanofrog]

I have had a lot of problem trying to build a stable SAS external enclosure with SSD. When i saw the work of Rob at Barefeats, i bought a Stardom ST8 SAS with four Vertex 3 SSD (were cheaper than OWC). I could not format HFS+ the SSD array, even JBOD. I tried a RocketRaid 2744 and also Atto R680. No success. I downgraded to 10.6.7 from Lion. No success.
Now i finally gave up, put the four SSD in the internal bays (around 550 MB/s read and write) and put the WD disks in the enclosure. So, after shelling a lot of $$, i could not achieved the 1.5GB/s with the enclosure. SO, if anybody have a bunch of Vertex 3 working fine in a ST8, i would like to know how they did that.

The enclosure is just a "dumb box" (signals are just transmitted over wire, no active circuits between the card and disk, such as a SAS Expander).

In the case of ATTO:

If you check the Compatibility List (scroll down for SSD's), there isn't a single OCZ SSD listed, let alone the Vertex 3. So it seems those disks are incompatible. You could contact ATTO and OCZ to see if there's newer firmware that might get them operating, but I suspect you'll need to get a different card.​

Highpoint:

Their RAID products are garbage (hardware and software based products), so don't waste your time IMO (send it back if possible). It's all made by ODM's (Highpoint doesn't design or manufacture a single product they sell, so the hardware is uneven in terms of how it works/how well it works, and the support dept. won't be of much help, if any at all).​

As a general rule, always check the Hardware/Product Compatibility lists before buying disks to be used with a RAID card, as they require different recovery timings in the disks, and need to be tested (some will even state the firmware revisions if it took a rewrite on either the card or disk, and in some cases, both).

So either return the existing OCZ disks, or change the RAID card (Areca has been shown to work with OCZ SSD's IIRC).

Of particular note, I don't particularly like OCZ for SSD's (their QC is horrible), but more importantly right now with 6.0Gb/s SSD's, is there are problems with the SandForce 2281 SSD controller (any make using it if you search). So I'd take a look at 6.0Gb/s disks with Marvell controllers right now.

Just a thought anyway.

Regardless of what disks you use however, check the Compatibility Lists before you buy anything (Yes, I'm repeating myself here, but I can't stress this enough if you don't like being a guinea pig and going through the RMA's for gear that doesn't work).

Pretty much all current SSDs use 2Xnm flash which is rated for 3000 P/E cycles. 3Xnm can still be found in some older models but 5Xnm is pretty much dead and would cost a fortune anyway if you found one.

HET-MLC is the new thing though. Cheaper than SLC (as it's still Multi-Cell), yet much better endurance than regular MLC, although it's still way behind SLC and also slightly behind 50nm MLC. Intel is set to release 710 Series later this year with HET-MLC, might be worth waiting if SLC is out of budget.

The better NAND is still available, but it's expensive. So manufacturers have shifted to the least expensive parts they can get as a means of reducing costs.

eMLC (and similar; i.e. 30k write cycles) is quite interesting, but it needs to come down in cost before it's used widely (at current prices, it's aimed at enterprise devices, not consumer models). Perhaps Intel will get their production costs down enough to where their HET-MLC will make it into consumer parts (and reduced cost enterprise variants, as SLC is still too high, even for some enterprise users that would love to get their hands on it).

 

[porthosmac]

Thanks Nano for your advices.
I have actually an Atto R680 working well. I cannot return the SSD because I have them for 2 months now. Nevertheless, they work well inside the Mac Pro but I am surprised that I dont get higher results than 550 ( max limit around 640 isn't it?)
I have a few questions about my setup.
May i PM you?
Thanks

 

[nanofrog]

Thanks Nano for your advices.
I have actually an Atto R680 working well. I cannot return the SSD because I have them for 2 months now. Nevertheless, they work well inside the Mac Pro but I am surprised that I dont get higher results than 550 ( max limit around 640 isn't it?)
I have a few questions about my setup.
May i PM you?
Thanks

Real world throughputs of 6.0Gb/s SATA is only 540 - 550MB/s.

BTW, what controller are the SSD's connected to (ICH is only 3.0Gb/s, so cut real world throughputs in half)?

And Yes, you're welcome to PM me.