I have been using the encrypted home directory feature for years and I can tell you that while it behaves fine under normal circumstances it will bring your machine to its knees when doing any kind of intense file operations.
I have a quad-core Pentium i7 with 16GB of RAM from System7. By any measure it is a lightening fast laptop with a SATA 7200 RPM drive. Just today when I was unzipping a file with 20,000 small text files in it (take 10 minutes), my system is essentially unusable. Everything that touches the file system has a 1-2 second delay...including the web browser. My experience is exactly that of the OP -- the encrypted home directory is about 15x slower than unencrypted.
I didn't think anything about it because I am so used to it (this is my 4th laptop). On the wild chance that somebody has a tip on how to improve it, I thought I'd search here.
I encrypt my home directory because I HAVE to. If you don't have to...then don't.
My apologies for posting this as an answer, but comments would not get the attention this needs. It is my considered opinion, that your drive is in imminent danger of failing.
Please make a full system backup right now.
If you don't know how to make a system backup, please refer to this question. You're user type 4. If you need any further help on making a system backup, leave a comment below this answer.
What??? You're still here? Go away and make the system back-up first! (Disk-to-image)
Then, boot from a LiveCD and issue the following command:
sudo apt-get install smartmontools
Then:
sudo smartctl --scan
and for all /dev/?d?
lines below that:
sudo smartctl --info /dev/?d?
until you see: Device Model: INTEL SSDSC2BW240A3
and verify that:
SMART support is: Available - device has SMART capability.
SMART support is: Enabled
and from now on, wherever you see sda
, replace that with your own ?d?
(sda
is the most common, so yours will probably be this too)
Run:
sudo smartctl --all /dev/sda
and post the output of that to http://paste.ubuntu.com and provide a link to the ouput back here. Then:
sudo smartctl --test=short /dev/sda
and post the output of that (by doing another sudo smartctl --all /dev/sda
) to http://paste.ubuntu.com too and provide that link to its output back here too.
Hopefully I'm wrong
and I can delete this answer safely and we can get back to encryption.
Best Answer
Well in the past, encrypting the system would have a strong performance hit since all the I/O and processing that needed to be done between encryption and reading/writing to the disk. But since a couple of versions ago, the performance hit is less than 5%. I would even be so bold as to say it is less than 1% since, with some tested I did, the video performance, copy/paste, hdd benchmark and speed of boot were almost the same.
And since you are using Ubuntu 12.10, there is even less of a performance penalty.
Here is a link of the Performance on Ubuntu 11.10 with and without Encryption
And here is a very old benchmark on how it looked on 9.10
As you can see the performance has gone up since 11.10 and you are using 12.10, so the performance is basically the same. I was actually amazed n how it was running when I first tested this on 12.04.