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Encrypting 4TB external drive taking days?

Discussion in 'OS X Mountain Lion (10.8)' started by micrors4racer, Oct 5, 2012.

  1. macrumors 6502

    #1
    It has taken about 2 days to encrypt my 4TB drive with about 2TB of contents in it. Is this normal? While I know its okay to unplug it and let it resume encrypting at its own leisure everytime I use it I want to know if it really takes this long for a 4TB drive. I am checking the progress by the command line "diskutil cs list". It says it has encrypted 3.8TB out of 4TB and the status is not fully secure but it does ask for a passcode when I plug it in if I eject it and works normally otherwise.
     
  2. #2
    What connection interface do you use? USB 2.0 or USB 3.0 or Firewire 800 or Thunderbolt?
    If it is the first, then two days seems reasonable, as the OS has to read the available contents, encrypt them and write the data back onto the HDD (now encrypted) while deleting the non-encrypted data. USB 2.0 offers a maximum speed of 37 MB/s, but on average it is more around 30 MB/s, which means, if the process is being done constantly at 30 MB/s and you have that much data (3.4 TB or so), then it takes almost 1400 minutes to read that much data and another 1400 minutes to write that much data (3.4 TB). 1440 minutes are one day.
     
  3. macrumors 6502

    #3
    I am using a raid drive with the firewire 800 port. It just got done a couple of hours earlier so your calculations are correct. Would the drive have encrypted faster if it was freshly formatted with nothing in it?
     

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