High(ish) end SSDs

[Tannin]

I have a customer who might be looking at a system to do some serious number-crunching (merging hundreds of photographic images for mapping purposes). This is not the time to spec it out in any great detail as he has to talk to his higher-ups first and see if they are happy for him to spend several grand to reduce the current batch processing time (around 12 hours). If he goes with it, we will need a big CPU (presumably a higher-end i7), lots of RAM (probably 32GB), and a fast SSD, which will get hammered with lots of writes. I understand that the SSDs essentially fall into two camps: consumer and server grade, and that the cheaper consumer ones don't stand up well to heavy write loads. What would be a sensible sort of SSD to be looking at for this? 512GB would be comfortably big enough as finished jobs all get archived to off-line storage.

(Just a rough idea please, gentlemen; it's only an initial inquiry at this stage and I'll come back for more detailed recommendations if and when his management give him the OK.)

PS: he's going to come back to me on whether his application can utilise a GPU.

 

[Handruin]

Regarding your concern of server vs consumer grade SSDs, you may want to take a quick read in this thread related to SSD endurance testing. My point being, you may not need to recommend a server-grade drive when a consumer-grade drive might be just fine. P5-133XL has updated the very first post in the thread with the link to the 600 TB (yes, Terabytes) of data written to the drives and the results of the test. From the looks of things even the TLC drives are still hanging in there even though they've had some bad blocks remapped.

As for a suggestion of a 500GB+ drive, I'd go with whoever has a company that might be around long enough to fulfill an RMA. I own two Samsung 840 pro 256GB, 2 Samsung EVO 512GB, and one Crucial M4 256GB. Of the lot I've had minimal issues with any of them. My use case and workload is not of the type you're looking for so I'm probably not a good sample. If performance consistency is key, perhaps an Intel Intel S3700 might be the answer but when you look at the price you're going to want to charter a flight to the USA and hit me with that bag of Micropolis drives and still spend less than what that drive costs.

How about the Samsung 840 Pro 512GB or a Crucial M500 480GB? Both are MLC NAND. If you or your customer can stomach a little more cost and wait a little while longer, the Intel SSD 730 480GB might be a good match if consistency over time is more important than short-term IOPS.

 

[Tannin]

Excellent! Thanks Doug for a concise and comprehensive answer. That's given me a good basic grasp of the landscape; I'll sit back and see what my customer's company wants to do before going any further with this.

 

[Howell]

Hard to know what you mean by "stand up well". Doug has answered your question regarding wear out but I actually took your question to be about write speeds. If you leave 10-20% unpartitioned space at the end of the user accessible area you will create a cushion that will help preserve both write speed and wear out. You might miss out on enterprise grade firmware though. The jury is still out.

 

[Handruin]

This customer's situation might benefit from a workflow analysis to better understand the problem that needs to be solved before even approaching a solution (like an SSD). The general description of the problem suggests that the CPU could be starved (not 100% utilized on all cores) during the processing event which could lead to an IO bottleneck. Depending on what the size requirements are, maybe a RAM drive might actually work since the end result isn't required to live on the aforementioned SSD. Another suggestion could be one of the newfangled PCIe SSD implementations to get even the utmost performance edge from the storage component. If the time savings can be measurable you might be able to come up with an ROI calculation to push this customer into a more-expensive solution if there are tangible benefits from time-savings cost.

It's a little pricey ($2000 USD) but something like an Intel SSD 910 offers up a potential bump in throughput along with some fast IOPS but unless the customer's actual underlying workload is considered and understood it will be like throwing money at a fire. Depending on how far down the rabbit hole you want to consider and go........fusion-io.

 

[ddrueding]

The other thing to consider is how many cores the software he has in mind will actually use. Some of the photo stitching apps I've used in the past did not fully utilize all the cores I had, and some didn't use all the RAM (stopping at 6 cores or 16 GB). PTGui is excellent and the newer versions easily max out even multi-CPU Xeon monsters. The software that came with my GigaPan Epic, not so much.

 

[CougTek]

If you can get a hold of it, the HGST Ultrastar SSD800MM #0B28587 (the 800GB model) is probably the fastest 2.5" SSD you can get. It's also approximately 4000$. Faster than that, as the others told you, you have to go PCI-E. A Virident FlashMax II 2.2TB (their fastest model as the 4.8TB model is slower) will cost you approximately 10000$. It doesn't feature as consistent write performance as the 2.5" HGST SSD, but it has much higher average IOps on most type of loads (except for Oracle databases).

 

[ddrueding]

And before you get too crazy on the SSDs, this application (high STR, few seeks) works really well with RAID-0 setups. My Thinkpad W540 shipped with two SSDs in RAID0 from the factory. An OK 998MB/s per CrystalDiskMark.

 

[Tannin]

Cheers lads, this is all good stuff to consider. But first things first: before anything else, my customer has to convince his management (and himself!) that replacing their current overnight batch processing routine (~12 hours for a typical job on their current machine which is apparently some sort of Mac dual booting into Windows 8 ) is worth doing. Doubtless the 12-hour process is a bit annoying for the hands-on staff, but is it actually costing them money?

I have discovered that their software does use multi-cores effectively (certainly up to 6, dunno about more than that), and that it does not utilise GPUs. They regularly max out the 8GB of RAM in the Mac, which is a dual core.

So, for now, this can sit on the back burner pending a callback from him.

 

[CougTek]

If it's RAM and processing power they need, an HP DL380p #748303-S01 (2U) with 2x E5-2690v2 (3GHz/10-core each) and 32GB of RAM should cost ~6800U$. It comes with only two 16GB sticks, but you can add more at ~260U$ per 16GB DDR3 1866MHz ECC stick. You can also put any 2.5" drive you want, as long as you buy the drive sled from a third party seller. I've tried the Corsair Neutron GTX and some Marvel-based Intel SSD into those and it worked well. You can put up to 8 drives in the SmartBuy server kit. The HP 420i RAID controller will allow you to configure any kind of RAID.

 

[sedrosken]

I was under the impression that SSDs outlasted HDDs because of their lack of moving parts. Is this not the case?

You can't write to an SSD as many times as you can an HDD?

 

[Handruin]

I was under the impression that SSDs outlasted HDDs because of their lack of moving parts. Is this not the case?

You can't write to an SSD as many times as you can an HDD?

It's possible SSDs can outlast HDDs but by nature of NAND, they do wear out. Read this wiki page on how NAND used inside SSDs wears out over time.

 

[Mercutio]

I was under the impression that SSDs outlasted HDDs because of their lack of moving parts. Is this not the case?

You can't write to an SSD as many times as you can an HDD?

SSDs do outlast traditional disks on that basis, but the memory cells that make up SSDs have a limited lifespan of their own. After a certain number of writes, the memory cells stop responding to changes and have to be marked unusable. Eventually enough cells wear out in that fashion such that the drive becomes faulty. In theory, this is something that should be predictable on the basis of utilization, and the drive's own firmware is supposed to distribute writes to different memory cells as frequently as it can, but it still means that a drive that is being used is also a drive that is not going to live forever.