Comments on: PGP Disk Encryption Safe for Solid State Drives

By: Robert Nicholson

Robert Nicholson — Wed, 03 Jun 2009 23:43:43 +0000

I remember the WDE overhead on the X-25M being significant in the past but it was all relative the speed of the drive. I expect the overhead to be even worse after the recent X-25M firmware update.

By: Sebastian

Sebastian — Wed, 03 Jun 2009 22:48:49 +0000

Hi,

I’ve been using PGP WDE on a regular HD for a few weeks now, and I’ve been pleasantly surprised by the performance—compared to FileVault, that is.

I’ve been wondering, though, how the performance hit on SSDs is compared to a regular disk with PGP WDE. In other words, is it worth it buying an SSD if one intends to use it with PGP WDE?

And if so, does that only apply to the X25 (being the cream of the crop) or to slower SSDs as well?

By: Robert Nicholson

Robert Nicholson — Fri, 09 Jan 2009 20:40:17 +0000

Yes that’s what I’ve observed but the folks are PGP are, in my case, saying that the benchmarks aren’t accurately reporting the true numbers.

By: Paul Stamatiou

Paul Stamatiou — Fri, 09 Jan 2009 18:24:06 +0000

I actually updated that article last month. From the post:

Update 12-3-08 After having used PGP WDE on a faster computer with an SSD, I began to notice that with WDE enabled, the reads and writes were considerably slower. So I ran a few benchmarks and discovered that this was in fact the case – up to 4 times slower.

By: Robert Nicholson

Robert Nicholson — Fri, 09 Jan 2009 18:16:06 +0000

The original article said that it doesn’t affect performance?

On my Intel X-25M running Quick Bench before and after encryption I see the following numbers that do suggest there’s a big overhead introduced when the drive is run thru WDE

Random reads which were previously 233 MB / sec are now 28 MB / sec.

QuickBench(TM) 4.0 Test Results
©2000-2007 Intech Software Corp.
Test file created on Wednesday, December 24, 2008 at 10:04:15 AM
Test Volume Name: Macintosh SSD
Test Volume Type: MacOS Extended
Test Volume Size: 74.210 Gigabytes
Test Volume Free Space: 24.735 Gigabytes
Allow Disk Cache Effects: Disabled
All reads and writes performed sychronously
Standard Test Results
(Cycles: 1)
Seq. Read Seq. Write Ran. Read Ran. Write
4 KB 31.585 20.208 9.353 27.323
8 KB 58.744 45.162 20.763 27.078
16 KB 92.027 60.741 36.307 54.145
32 KB 112.122 29.952 63.771 19.485
64 KB 136.029 61.689 101.707 51.064
128 KB 169.068 67.01 140.681 44.506
256 KB 208.844 26.506 186.3 33.99
512 KB 229.571 57.076 214.202 49.319
1024 KB 243.366 51.743 233.922 42.058
Standard Ave 142.373 46.676 111.89 38.774

Standard Test Results
(Cycles: 1)
Seq. Read Seq. Write Ran. Read Ran. Write
4 KB 18.242 11.874 11.602 11.584
8 KB 23.325 20.067 14.99 8.954
16 KB 25.948 24.82 21.583 19.924
32 KB 28.316 26.754 24.557 15.061
64 KB 28.626 25.994 26.767 22.005
128 KB 29.789 21.122 28.318 12.667
256 KB 28.556 23.153 28.637 18.969
512 KB 30.612 23.109 28.664 18.175
1024 KB 30.517 23.287 28.507 18.57
Standard Ave 27.103 22.242 23.736 16.212

By: mike

mike — Mon, 03 Nov 2008 18:50:34 +0000

The wear leveling could cause more writes if you are encrypting the SSD and you are using different size blocks for encryption and for wear leveling. For example, if the encryption blocks are 4MB and the wear leveling is 2MB, you would always be writing to two blocks, where you would only write to one block otherwise in some cases. Like Jon said though, the wear leveling schemes are mostly proprietary, so there is sometimes no way to know what size blocks the internals of the drive are using.

Saying there is no detrimental effect would be wrong in my opinion. At best there is no detrimental effect, but no gain. At worst, you could be decreasing the life of your drive by at least half.

I think you should ask the manufacturers the same question and see what they say. They would know better since they know what algorithms they are using for their wear leveling.

-woz

By: Parantar

Parantar — Mon, 03 Nov 2008 13:15:22 +0000

i’ll try that too…

By: David Moore

David Moore — Mon, 03 Nov 2008 13:04:56 +0000

I am seriously considering it but will be at work soon and not willing to pay to have it on their machine and my machines will always be at home.

I am also waiting to see you review PGP email :P

Oh and I may wait for snow leopard before I move onto PGP

By: Klaus Bjarner

Klaus Bjarner — Mon, 03 Nov 2008 10:53:45 +0000

Hi Paul

I installed WDE yesterday after reading your review, and must say, that I am most pleased. The software and pre boot works perfectly. I have purchased the entire suite, and really likes the way PGP implements e-mail encryption with automatic public key look up on the addresses I address e-mail to. A sweet piece of software, that comes with a price tag, but worth every dollar in my opinion. Thanks you for a great review of PGP WDE and a great blog.

By: James Heath

James Heath — Mon, 03 Nov 2008 09:30:05 +0000

i’ve strongly considered encrypting my personal documents since your WDE review but given my situation, the only use it would serve was if my macbook was stolen. I don’t store much personal information on my hard drive, in the form of text documents, but of course, there is the information stored in keychain and cookies.

By: Tom Schlenkhoff

Tom Schlenkhoff — Mon, 03 Nov 2008 07:27:02 +0000

Remember to remove the hibernation file, though, like here: http://www.tomschlenkhoff.com/2008/06/macbook-pro-crashing-fix-sleep-issues-and-get-2gb-for-free/