I'm curious about (and was unable to find documentation for) any size limits for FileVault in OSX (10.9.5 Server). I'm concerned about any sort of corruption/instability that could occur after encrypting a 70-100tb logical disk.

I've run into this as an issue with volumes larger than 70tb with TimeMachine and had to switch to a different product for my backups.

Ignore the "why are you doing this" or "why are you not using linux/bsd". For a wide variety of reasons, I'm stuck with OSX for this project and am unable to split the partition into smaller segments.

Any insight would be much appreciated!

1 Answer 1


According to Apple the maximum volume size and file size (using Mac OS X v10.5.3 or later) of a volume formatted with the HFS+ file system is close to 8 EB (exactly 2^63 - 2^31 = 9,223,372,034,707,292,160 B). This is also valid for encrypted volumes.

One fact cannot be concealed: the monstrous Logical Volume (the FileVault2 "envelope") is highly vulnerable to drive failure. The failure probability is comparable to a RAID0. Since FileVault doesn't use evenly spread chunks you may recover more data after a drive loss.

Here is a comparison for 10, 11 or 12 disks (8 TB):

Survival probability (for new 8 TB disks and being optimistic):

Nr of disks  1st year 2nd year 3rd year 4th year 5th year
         10       84%      37%      15%       8%       5%
         11       83%      33%      12%       7%       3%
         12       82%      30%      10%       5%       2%

If the disks are smaller than 8 TB (and the number of disks is higher) the survival probability is even worse.

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