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What allocation size to use?

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December 13, 2011 11:25:01 PM

Hi, I am going to be using my Corsair 180GB ForceGT drive in my Toshiba laptop. OS will be Windows 7 Ultimate 32-bit.

I am wondering what unit size to use -- From what I can tell, 64K gives the best performance - however, being that this is a laptop and only has room for one drive, space is also at a premium. This was the largest SSD I could rationalize myself into actually paying for. If I set the (block? cluster?) size to 64K, the amount of space wasted will be phenomenal, because I have many small files.

Speaking of which, that's the main concern - I have probably a hundred thousand very small files (i.e. in the range of just a few kilobytes) if not closer to 200 thousand. No joke; when moving the data off the old dying drive to a temporary drive, there was 607,000 files (!). I would imagine I’ll be wasting dozens of gigs of space if I set to size to 64K. So let's say I go the opposite route, for most savings, and go with 512 bytes? Another option to consider would be the default of 4k and enabling whole-drive Compression.

What size is going to be the best tradeoff between realized SSD speed potential and not wasting a ridiculous amount of space?

Thank you.

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December 14, 2011 11:35:51 PM

I would go with 8192 bytes if I were you.
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December 16, 2011 2:13:31 AM

With so many small files, I would use 512 bytes.
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January 9, 2012 12:57:30 AM

For those who may be visiting this thread from the future, ultimately I used 4KB. While this will waste some space with all those tiny files, after doing some research I learned that apparently the architecture of current (2011) SSDs are based on blocks (or whatever the word would be) of 4KB size. Some are 8KB, which I imagine will be more common for you since you're reading this from the future. Anyway, going far below or above 4KB will actually cause write cycle "waste" for the drive, meaning that in the long run you'll actually reduce the life of your SSDs by using very small or very large units. Perhaps this is not a guaranteed fact, but definitely a good enough reason for me to stick with 4KB Default.

PS: The default being 4KB isn't some magical Microsoft SSD Optimization, it's the default for all modern drives of any type, at least that i've seen. Just an FYI for those of you who think OS Vista/7 is prescient or something. Nope, it just happened to use the same size as default that SSDs will want. Serendipity, not genius :p 

Thanks, and Cheers!
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