Jeff Bastian <jbastian@xxxxxxxxxx> writes: > What kind of performance hit should full disk encryption entail? > > I installed F9 yesterday under VMware Fusion 1.1.2 and enabled disk > encryption. It was working fine until cron fired up makewhatis. At > that point the system became so sluggish it was basically unusable. > Mouse clicks would sometimes work, sometimes get ignored, and some key > strokes would get ignored, others would get doubled (i.e., typing > foo' might end up with 'ffo' on the screen). > > According to 'top', makewhatis was consuming the most CPU, but only > about 4%, followed by kcryptd. However, the CPU was spending 85%+ on > system tasks. > > I noticed it was taking a long time to run makewhatis, so I ran 'time > /etc/cron.weekly/makewhatis.cron' to see just how long and got: > real 34m44.606s > user 3m18.520s > sys 13m46.823s > > I switched back to my Fedora 8 virtual machine (same host) and > repeated the test and got: > real 7m1.667s > user 2m45.410s > sys 3m4.970s > > > That's quite a performance hit for disk encryption... Is there > something I can tune to speed this up? Or maybe I should just encrypt > /home instead of the whole disk. > > FWIW, I have VMI enabled in VMware Fusion, and I'm booting with kernel > command line args > elevator=noop clocksource=vmi-timer > on both systems. > > Jeff I can't speak to your specific implementation, but in the past over several versions of FC/F, when I have run performance comparisons with hdparm, using dm-crypt/LUKS with 256 bit AES on a 7200 rpm HD, I have seen about a 10-15% hit in throughput. Your figures above suggest that something else is going on, perhaps related to the virtualization overhead and I don't know enough about that to comment in an authoritative manner. HTH, Marc Schwartz -- fedora-list mailing list fedora-list@xxxxxxxxxx To unsubscribe: https://www.redhat.com/mailman/listinfo/fedora-list
