[Appleman]

Trying to enable FileVault, I get the following message, while my harddisks are resp. 160GB and 80GB:

Turning on FileVault requires an additional 4082,4 GB of free disk space...

[tooki]

'Tis a bug.

tooki

[Appleman]

Originally Posted by tooki

'Tis a bug.

tooki

And this bug has been there since Panther? Solutions?

[nonhuman]

If you run at anything near full capacity with your hard disks, especially if you're constantly adding and deleting files, don't use FileVault! When you delete a file you will actually lose free space until you log out or restart and allow it to 'recover' that space (which can take quite a long time depending on how much space we're talking about.

I work with a lot of video and am constantly suffling around gigabytes of data. With FileVault turned on I was routinely running out of disk space (because I was deleting gigabytes of data after burning it to dvd) and then having up to 2 hours of downtime because your computer is unusable while it's recoving that wasted space.

On top of all that I couldn't disable it because your hard drive needs to have enough available space to duplicate everything in your home folder to disable it. Eventually I resorted to creating another user and just copying everything over to that home folder (with plenty of breaks to recover the disk space that I was losing when deleting the files from my original home folder, of course). Took me nearly two days just to disable FileVault...

[Appleman]

Originally Posted by nonhuman

If you run at anything near full capacity with your hard disks, especially if you're constantly adding and deleting files, don't use FileVault! When you delete a file you will actually lose free space until you log out or restart and allow it to 'recover' that space (which can take quite a long time depending on how much space we're talking about.

I work with a lot of video and am constantly suffling around gigabytes of data. With FileVault turned on I was routinely running out of disk space (because I was deleting gigabytes of data after burning it to dvd) and then having up to 2 hours of downtime because your computer is unusable while it's recoving that wasted space.

On top of all that I couldn't disable it because your hard drive needs to have enough available space to duplicate everything in your home folder to disable it. Eventually I resorted to creating another user and just copying everything over to that home folder (with plenty of breaks to recover the disk space that I was losing when deleting the files from my original home folder, of course). Took me nearly two days just to disable FileVault...

Thanks for the explanation. As I do quite some video as well, I better leave it that way then. Thanks.

[workerbee]

Originally Posted by nonhuman

I work with a lot of video and am constantly suffling around gigabytes of data. With FileVault turned on I was routinely running out of disk space (because I was deleting gigabytes of data after burning it to dvd) and then having up to 2 hours of downtime because your computer is unusable while it's recoving that wasted space.

On top of all that I couldn't disable it because your hard drive needs to have enough available space to duplicate everything in your home folder to disable it.

What if you'd put all your big files (video, iTunes library, ...) into a shared directory, and only keep your essential stuff in your own, file-vaulted home directory? That would save you from unneccessary disk space recoveries, and from the speed hit FileVault has on disk I/O as well.

[nonhuman]

Originally Posted by workerbee

What if you'd put all your big files (video, iTunes library, ...) into a shared directory, and only keep your essential stuff in your own, file-vaulted home directory? That would save you from unneccessary disk space recoveries, and from the speed hit FileVault has on disk I/O as well.

Yeah, that would work too, although I don't know how well iTunes would deal with you moving the Iibrary around. But I just don't like working that way unless I have to. For me the benefits of using FileVault didn't come close to outweighing the annoyances, and I suspect that most people would rather leave it off than have to rearrange their hard drive to suit its needs.

At the very least I think it's important that people be aware of the limitations of FileVault and the problems that it can cause in some cases.

[Goldfinger]

Originally Posted by nonhuman

Yeah, that would work too, although I don't know how well iTunes would deal with you moving the Iibrary around.

Works perfectly.

[workerbee]

Originally Posted by Goldfinger

Works perfectly.

Yep.

[nonhuman]

Originally Posted by Goldfinger

Works perfectly.

Cool. I never had any reason to try.

[wataru]

For anyone wondering, the reason you lose space as described above is beacuse FileVault turns your home folder into a sparse disk image. Sparse disk images grow as their content grows, but they do not shrink until you "compact" them. A disk image cannot be open during compaction, so this can only happen while you're not logged in.

You can manually compact disk images by running in the Terminal

Code:
$ hdiutil compress myimage.sparseimage

According to man hdiutil

compact improves the experience of using a SPARSE image for persistent storage by reclaiming unused space in the image. Beware that SPARSE images can enhance the effects of any fragmentation in the filesystem.

I imagine this is because compacting probably "optimizes" (like Norton's Speed Disk) the data in a sparseimage in a half-assed way by filling in gaps in the data with incomplete chunks near the end instead of actually defragmenting. (For example: the data is "abcdef." Delete "b," then it's "a cdef." Instead of making it "acdef," it does "afcde.")

[Appleman]

Originally Posted by Goldfinger

Works perfectly.

yep (2)