I've heard that some cheap SSD's have really sloppy wear leveling algorithms which don't work if the drive is more than 50% used (not in terms of stored data, but in terms of total writes) - The drives don't expect more than a certain percentage of sectors to EVER be used, so the process of encryption, which writes to all sectors, really confuses them. The drive is kind of treated like a tape, new writes are written to new unused areas of the SSD until it gets full, then it starts overwriting at a far reduced performance.
If you experience this you should take it up with the SSD vendor themselves, or look to replace the drive with one from someone else who has a better wear leveling alg.
Hey! I've got Corsair SSD 256Gb. After encryption (EEPC 5.2.2):
0.5Kb blocks, 8Mb/s read and 2.1Mb/s write
1024Kb blocks, 99Mb/s read and 99Mb/s write which is about the same as 7200 rpm HDD.
The partition is 100% of the drive, not sure would it be better if I left a part of it empty. Probably not. Quite disappointing performance.
Seems our IT would not upgrade any time soon.
Any chance for a patch of some kind? I do not think this drive falls into the category of some cheap SSD's.
Sorry no, this is not something we are able to back port. Your company would need to migrate to the latest product version, or maybe even wait for v7 at the end of the year.
Cool, np! Thanks for checking! Will wait till v7 and ask to upgrade as an exception or something.
Got SSD un-encrypted before repartitioning. What a difference (block - Mb/sec)!
Encrypted: 0.5Kb - 2.19Mb/sec, 4Kb - 14.8Mb/sec, 64Kb - 66.81Mb/sec, 256Kb - 90.33Mb/sec, 1024Kb - 99.09Mb/sec
Unencrypted: 0.5Kb - 2.14Mb/sec, 4Kb - 16.8Mb/sec, 64Kb - 175.37Mb/sec, 256Kb - 331.35Mb/sec, 1024Kb - 446.86Mb/sec
Which is 2x - 4.5x speed drop starting 16Kb blocks (linear vs. random read is about the same). So when I work with nicely aligned large SQL databases, it seems I loose alot. Basically safeboot got SSD to the speed of HDD which I have as the second drive.
I am still not getting why read speed is dropping that bad. If load levelling fails with full drive encryption and writes are slow. How would it affect reads?
Next is repartitioning the drive and leaving 20% un-partitioned. Will report back.
You are using aes-ni yes?
But what alg did you pick for eepc?
How do I check? Not sure if I could pick it as it uses company defaults. In Modules it references "SbAlg.sys" 4.2.11 (most of other modules are 126.96.36.199 or 188.8.131.52). And this SbAlg.sys is from 2008, SafeBoot FIPS AES Algorythm (256 bit). Is there a switch?