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SSD - Risky Business?

Posted by Javed Lodhi on Dec 2, 2008 12:02:01 PM

Now before we kick off on this topic, first let us decide what risk factor are we talking about - Performance, Stability, Durability, and Price?

After coming across Mario Apicella's (Storage Advisor) article, I am not sure I do agree to all of it since my experience over SSDs is a bit different but you see this varies from situation to situation. I do agree that SSD costs a lot more than the typical mechanical drives at the moment but then when you go for an SSD, price is not your primary concern due to one very simple reason - you are aiming for a better and far more stable solution. You see, Apicella has benchmarked with SATA SSD drives but did not provide any feedback over SAS based SSDs. Now as you may know that SAS drives perform better as compared to IDE, SATA or SATA II since SATA is half duplex while SAS drives are based on Serial Attached SCSI where we all know that SCSI drives perform RW in a duplex mode, outclassing SATA/II in performance. I hope you are getting my point. See! You just cannot say that SSD drives are a risky trade because of a fact that the price difference between SSD and the conventional mechanical drives is significant but my point is that, not everyone would order an SSD. People who ask for an SSD in their solution are actually aiming at a far more stable and LOW-RISK solution and price to them does matter, to the extent where they would compromise stability over price.

Now I wouldn’t say that by plugging in a SSD, you would get phenomenal increase in IO but it does perform quite decently as compared to the other members of storage medium family. Yet again, an SSD is not just of one type and depending on the type of SSD, performance varies.

One interesting point that I see a lot of people reviewing SSD miss out on is, Virtualization. You see, plugging in a 2.5” SATA or SAS based SSD drive in an Intel Blade Server will give you a much better performance as compared to mechanical SATA or SAS but when we talk of virtualized storage especially coming to Intel’s Modular Servers, how well will these drives perform? See, it’s not a discussion we can wrap up in a couple of paragraphs and jump onto conclusions. In continuation of this blog, I will post one of my researches over SSD technology and the performance benchmarks considering the price factor in mind but for now, I would say that SSD is expensive but then the performance gain and stability is better than the mechanical drives which a lot of customers actually aim for. Adding more to it, price of SSD drives is dropping faster than those of mechanical drives; and as such the days of the mechanical hard drive are numbered. We are constantly hearing about the fruition of solid state memory technologies (such as MRAM which has been theorized since the 1970's) that provide more density and reliability, lower power, and faster write times. Mechanical hard drives are now once again bottle-necked by technology since perpendicular heads have become main-stream as have the corresponding aerial density increase that accompanied perpendicular heads.

These are a few simple facts and I think it would not be fair to say that solid state upgrade is a risky business at all. Perhaps the subject should have been, “Solid State Upgrades - Cost or Peace of Mind?"

--

Javed Lodhi



Add a comment Leave a comment on this blog post.
Dec 3, 2008 3:18 AM Guest Ulrik Lunddahl  says:

Where does this Peace of Mind come from, everyone seems to agree that SSD drives in any form is better than mechanical drives, but are they, are they error free per definition just because they are not rotating ?

Dec 7, 2008 10:58 AM Guest Daniel Walker  says in response to Ulrik Lunddahl:

From what I have been able to understand, the author here is not trying to emphasize that the solid state drives are error free but I guess he is talking about better performance.

Dec 24, 2008 9:57 AM Guest Alexander Ivanoff  says in response to Daniel Walker:

I've read (sorry I can't find the source right now) that after multiple tests of SSD drives from different manufacturers and the result was quite interesting  - only 50% of SSD drives showed a better performance than usual HDD 7200rpm drives.

Dec 24, 2008 1:48 PM Guest Chad  says in response to Alexander Ivanoff:

WHICH Brand and model of SSD and GENERATION you're talking about matters a great deal.

 

Additionally, if you look at power consumption (even if all other aspects were the same), then SSDs are the CLEAR winner. A small to medium data center runs about 1800-2000 HDs (roughly). For that much power you can run about 95,000 SSDs.

 

Additionally, the latency numbers and throughput numbers of enterprise class SSDs (vs cheap consumer SSDs that DON'T have the throughput of enterprise stuff being WAY too cheap) are simply astronomical compared with HDs.

 

Comparing the newest lower power enterprise drive numbers with the newest SSD numbers you get:

 

Roughly:

                    HD          vs           SSD

Latency:       3-6ms                    .85ms (that's POINT 85, less than 1ms)

RAID0:        ~150MB/s               ~400MB/s (this is on a SATA2 interface, I don't have SAS numbers)

Power:          3w (idle)               150mw (active)   .6mw (idle) (that's POINT 6, less than 1mw)

 

(Raid0 with 2 drives each)

 

The numbers are clear, do some research and don't use old information.

Dec 25, 2008 10:05 AM Javed Lodhi Javed Lodhi    says in response to Chad:

Alexander - As I mentioned that SSDs are not of just one type and with the evolution of SSDs, it has outclassed classical mechanical drives. I have tested and benchmarked SSDs performance myself and based on the facts, I have reviewed their performance. As for the 50% performance, I hope you have read it somewhere but I always provide reference to whatever quote so that the reader must know the authenticity of the statement and can read what others have to say before they conclude, anyway I appreciate your input and efforts; thank you!

 

Chad - Thank you for the performance benchmarks and even though you have posted results roughly, I appreciate your feedback; thank you!

Jun 23, 2009 2:23 PM Saad Shaukat Saad Shaukat    says in response to Javed Lodhi:

Hey Javed,

 

I hope you are doing good,

 

I have a query about the working Life of SSD over conventional HDDs? what is MTBF ?

Sep 2, 2009 12:38 AM Javed Lodhi Javed Lodhi    says in response to Saad Shaukat:

Hi Saad,

I am very well & hope the same for you.

MTBF depends on what model and tech-based SSD you are ordering. For instance, of 2, 000, 000 Hours while X25-E comes with an MTBF34nm based X18-M & X25-M comes with an MTBF of 1, 200, 000 Hours.

 

MTBF for conventional drives varied from technology to technology, for instance a SCSI drive typically had an MTBF of 1, 000, 000 Hours.

 

You can get detailed information on SSDs and the upcoming models based on 34nm technology here: http://developer.intel.com/design/flash/nand/ssd-info-center.htm

Thank you, have a great day!