I have a netbook with Windows on the second partition and Xubuntu (
/home) on the third partition. I selected to encrypt my home folder during installation. The performance of the netbook is adequate for the small machine that it is, but I'm looking to improve performance. I could not find much information about the overhead (CPU or drive) associated with home partition encryption. I ran the following, writing to my home partition as well as the the mounted Windows partition:
dd if=/dev/zero of=~/dummy bs=512 count=10240
dd if=/dev/zero of=/media/Windows/dummy bs=512 count=10240
The first returned 2.4MB/s and the second returned 2.5MB/s. Can I therefore deduce that there is very little overhead to home folder encryption? I'm not sure if the different filesystems will make any difference (
/home are ext3).
I don't know why I didn't use
/tmp instead of the mounted Windows folder. Only
/home is encrypted, so
/tmp is unencrypted ext3. The results of the
dd as above are astounding:
~: 2.4 MB/s
/tmp: 42.6 MB/s
Comments please? The reason I am asking this is that disk access on the netbook is noticeably slow.
I timed each of the
dd operations with
real 0m2.217s user 0m0.028s sys 0m2.176s
real 0m0.152s user 0m0.012s sys 0m0.136s
Edit: Output of
/dev/sda3 on / type ext3 (rw,noatime,errors=remount-ro,user_xattr,commit=600) proc on /proc type proc (rw,noexec,nosuid,nodev) none on /sys type sysfs (rw,noexec,nosuid,nodev) fusectl on /sys/fs/fuse/connections type fusectl (rw) none on /sys/kernel/debug type debugfs (rw) none on /sys/kernel/security type securityfs (rw) none on /dev type devtmpfs (rw,mode=0755) none on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=0620) none on /dev/shm type tmpfs (rw,nosuid,nodev) none on /var/run type tmpfs (rw,nosuid,mode=0755) none on /var/lock type tmpfs (rw,noexec,nosuid,nodev) binfmt_misc on /proc/sys/fs/binfmt_misc type binfmt_misc (rw,noexec,nosuid,nodev) gvfs-fuse-daemon on /home/USER/.gvfs type fuse.gvfs-fuse-daemon (rw,nosuid,nodev,user=USER)
Update 2012/05/01: More related links for reference: an (old) Phoronix test, a similar question here, a duplicate question here and a similar SuperUser question. A good summary answer here suggests that performance penalties are only noticeable on small/netbook (Atom) processors and SSDs.