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Re: [Fed-Talk] Lion FileVault
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Re: [Fed-Talk] Lion FileVault



Just to follow up on my own question from earlier.

I can confirm a roughly 12% impact on throughput on my personal MBP writing to a FileVault2 volume (roughly 190mb/sec vs 215mb/sec writing a test file to a SSD)

Slight, but tolerable CPU hit.. kernal_task hovered around 4.0% while writing to a *non*-encrypted volume, and about 35% when writing to an encrypted volume. So yes, I can see the difference when watching Activity Monitor, but it certainly isn't enough to cause major stress on the CPU and have fans spooling up. So roughly a 30% increase in CPU activity for one cpu core (out of the 4 available on my machine)....

Reads did NOT seem to be impacted as much in terms of throughput - averaged about 315mb/sec reads on both volumes, although again - kernel_task was basically a non-issue when reading from the "regular" volume, and bounced between 30-40% when reading from the encrypted volume.

(note - both volumes are on the same physical disk, just my "regular" and my "test" partitions on a 256gb SSD. Tests were done writing out 10-20gb files using DD, not the most scientific, but easily repeatable for testing purposes.)

Taylor


On 7/21/2011 4:15 PM, Taylor Armstrong wrote:
An interesting test would be to see what sort of CPU hit you encounter as well.... with SSD's, a 12% throughput hit isn't all that horrible, but I'm curious what impact it has on CPU doing the encryption/decryption on the fly. Will writing files cause my MBP to spin the fans up? Writing an encrypted DMG sure does....

Taylor

On 7/21/2011 4:10 PM, David Emery wrote:
I installed FileVault on an older MB Pro (that happens to have a Momentus XT Hybrid drive in it), ran XBench Disk Test, then enabled File Vault encryption and re-ran the Disk Test benchmark. FileVault inflicted a roughly 12% performance hit. This is not a scientific test for many reasons, but it's probably a good first blush.

Does Lion support FileVault encryption on external drives, too? How about Lion Server? (Now that it's out, I guess we can talk about such things, right?)

        dave
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David Emery,  703 298 3473 (c) 703 272 7496 (fax)
Supporting PdM Software Integration




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References: 
 >[Fed-Talk] Lion FileVault (From: David Emery <email@hidden>)
 >Re: [Fed-Talk] Lion FileVault (From: Taylor Armstrong <email@hidden>)



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