[dm-crypt] aes-xts-plain with aes_x86_64 makes my SSD 5x slower than my encrypted HD
marc at merlins.org
Thu Aug 16 09:43:33 CEST 2012
On Sun, Aug 12, 2012 at 03:49:29PM +0300, Pasi Kärkkäinen wrote:
> I didn't read the whole thread, but are you aware that many/most SSDs use
> internal processors for compression, deduplication, etc ..
> so if you write encrypted data to the SSD, it's not able to do it's internal magic,
> and thus you get a lot worse performance compared to non-encrypted data.
Only on some controllers like sandforce, the Samsung 830 wasn't supposed to
> So did you try benchmarking with *random* data *without* encryption?
> Also always first write to the disk, and only read after it has been already written to.
Yes, both were parts of my tests.
But, I owed everyone an update, which I just finished typing:
Basically, the samsung 830 just sucks. I got 2 of them, they both utterly
sucked. There is no excuse for an SSD being several times slower than a slow
hard drive on _READs_ (not even talking about writes).
I'm not sure how I could have gotten 2 bad drives from Samsung in 2
different shipments, so I'm afraid the entire line may be bad. At least, it
was for me after extensive benchmarking, and even using their own windows
In the end, I got a OCZ Vertex 4 and it's superfast as per the benchmarks I
posted in the link above.
"A mouse is a device used to point at the xterm you want to type in" - A.S.R.
Microsoft is to operating systems ....
.... what McDonalds is to gourmet cooking
Home page: http://marc.merlins.org/
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