Saturday, October 20, 2007

SSD again, exposing the lies this time.

There's a site at http://www.storagesearch.com/ssdmyths-endurance.html which pretends to be non biased yet isn't. They do present good information. They just spin it like FOX News does.

Here he eloquently muddles the picture talking about how things are complicated but the vendors have your best interests at heart. That they have done all sorts of work but won't tell you because they are afraid others will steal their great algorithms. Then he talks about the hypothetical nightmare scenario from hell. He figures worst case scenarios and concludes a disk will last 55 or maybe 80 plus years. And that's worst case. Well if you managed to make it down to where he starts off his BS you probably were jaded and half asleep. I'll cut to the chase.

He assumes a write is done evenly across the whole disk. Well to write across the whole disk rather is not worst case. Lets get real. People fill their disks up to capacity and then your paging and data file get rewritten to the same spot over and over again. Not across the whole disk.

Lets take the paging/cache file. It's going to hit the same part of the disk over and over. So all of a sudden you have taken it down from their 64GBs down to 1/2GB. All of a sudden you are working with a life span of half a year.

Now if we want to say they have good algorithms then they must be a lot of behind the scene disk management. Like it must have it's own OS that intelligently keeps track of what data is not getting rewritten often and what is. Kind of like a real time disk defragger. Do any of these SSD devices have that. I don't think so. So basically the redistribution is only being done when file space is returned and available for redistribution.

As your imagination can hopefully deduce now only open standard real time defrag programs, running on their own chip on their own OS on the SSD drive has the ability to spread the data evenly like the author claims happens. Until then you have to have the smarts to know whether a SSD disk works for you. Maybe they'll start shipping this, along with cache, to utilize the SSD properly. But it's still years off.

I'd like to know why this author is so biased in favor of SSD. Though it does not matter.

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