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SSD + filevault2 = slow write speed
- Thread starter dollystereo
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That is normal. FileVault 2 doesn't support hardware encryption and software encryption impacts IO performance negatively since the encryption is done by the host CPU.
http://www.anandtech.com/show/4485/back-to-the-mac-os-x-107-lion-review/18
http://www.anandtech.com/show/4485/back-to-the-mac-os-x-107-lion-review/18
What kind of speed did you get before enabling FileVault? Are you sure, that the encryption was fully completed, and the disk was not being indexed by Spotlight?
There is a clear performance impact with FileVault, but it should not be much worse than what you see in the article Hellhammer linked in his post. If you are getting significantly slower speeds, there's something else going on.
Check the Disk tab in System Monitor, with Show All Processes selected, and see if there's a process that is doing a lot of reads and/or writes.
There is a clear performance impact with FileVault, but it should not be much worse than what you see in the article Hellhammer linked in his post. If you are getting significantly slower speeds, there's something else going on.
Check the Disk tab in System Monitor, with Show All Processes selected, and see if there's a process that is doing a lot of reads and/or writes.
Agreed.... there is a slight speed hit with FV2, but nothing like the ~50% hit OP is seeing there. Something is wrong.
Agree with those who suggest something else is amiss. I have Firevault2 enabled on both my 2012 rMPB and 2008 iMac. Obviously, more noticeable impact on iMac but much of that has to do with limited ram--no noticeable impact on rMBP.
Wait a couple of months.
At the beginning it was as fast as no encryption, now it got slower.
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I have been using file vault for 6 months now, so all the disk is already finished encrypting, and the speed at the beginning was really good (250/500).
There is nothing about FV2 that would make it slower over time. It would get a bit slower as soon as you enable FV2, but FV2 would not make it degrade as time passes. You have got something else going on.
Here is something you can try if you want...
Turn off FV2 and wait for it to decrypt. Confirm TRIM is still active then restart in single user mode and type in "fsck -fy" (without the quotes). That will TRIM all unused blocks on the drive and should restore write performance. When finished type reboot.
Now try a speed test before and after FV2 and see what you get.
I on my third Mac using FV2 and it has never degraded speed after the initial small hit.
I've been using FileVault on a mid-2012 rMBP disk for more than 18 months, and speeds are as good as new. And the disk has been through heavy use, has been filled over 90% many, many times, etc.
Maybe there's an issue with the background garbage collection of your disk? Have you updated it's firmware? Have you enabled TRIM?
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I've been happy with the read/write speeds of my SSD with FV2 turned on. It is a little bit noticeable in the beginning but then you get used to it and don't even notice it. The biggest advantage is your data is now encrypted. In a day and age where MBPs tend to grow legs and walk off keeping your data secure is vitally important.
It's possible that the FileVault in newer Macs with Apple's SSDs supports hardware encryption, which would explain why there's no drop in performance. The SSDs are certainly capable of that, so it's totally up to Apple's software implementation.
My understanding is, that FileVault 2 uses AES-NI, but does not benefit from the built-in encryption of SSDs. FileVault 2 works with Core 2 CPUs, but without AES-NI support the performance drop is larger, than on Sandy Bridge or later. And AES performance has improved from Sandy Bridge CPUs, even more than general performance.
But that would not explain the OP's issue of speed decreasing over time.
I have trim enabled, I may try to disable FV and re enable it.
What I find weird, is that if I do 3 tests in a row, I get lower speeds each time. (180->120->80MB/s)
What I find weird, is that if I do 3 tests in a row, I get lower speeds each time. (180->120->80MB/s)
Before you do that try the trick I mentioned in post #8 and see if that helps.
Would TRIM be disabled on apple branded SSDs? I can see it occurring if you enabled TRIM on non apple SSDs and an update turned it off some how.
No, but in post #1 OP mentioned he has a Samsung 840 and had enabled TRIM, so it sounds like he does not have a OEM Apple SSD.
I will, thaanks
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"It would appear that FileVault, at least on a quad-core Sandy Bridge CPU has absolutely no overhead here. Given that Apple near-universally uses AES for symmetrical encryption, it's reasonable to assume here that FileVault is taking advantage of the AES-NI instructions on Intel's Core-i series of processors."
I dont understand your comment.
It basically means that the FileVault 2 encryption relies on AES encryption, which only the Core i3/i5/i7 processors support fully without any performance hits (because the i3/i5/i7 have AES-NI instructions in them).
If you don't have a i3/i5/i7 processor, FileVault is going to be very slow. For instance, a Core 2 Duo doesn't support AES-NI, so FileVault is going to be much slower as the processor just can't handle it.