ASUS Eee PC / Intel Atom: Disk Encryption Performance

While the ASUS Eee PC 901 doesn't have its solid-state disk drives encrypted by default, if you are storing any potentially sensitive information on this netbook -- or any mobile device for that matter -- you really should encrypt the data. When you lose a mobile device or it has been stolen, it can be a nightmare if your banking information was stored on there or even just passwords to your Internet accounts. However, what is the performance cost for fully encrypting a hard drive on one of these Intel Atom computers? In this article we are looking at the performance impact of fully encrypting the solid-state storage versus an unencrypted LVM within Ubuntu Linux.

Starting with Ubuntu 7.10 was install-time encryption support. Through an option in Ubuntu's alternate CD installer, the user can opt to have their LVM fully encrypted (including the SWAP partition but without the boot partition) where to boot Ubuntu the user will need to supply their pass-phrase. If no password is supplied, the system cannot boot nor can the encrypted partitions even be read. This encryption support is provided by dm-crypt within Linux. Sadly, it has been a year though and the Ubuntu Ubiquity LiveCD installer has yet to integrate install-time encryption support. However, that is for another story.

Back in March we had delivered Ubuntu Linux Disk Encryption Benchmarks using Ubuntu 8.04 Alpha 6 on an AMD Athlon 64 X2 4200+ system. This dual-core test system had 2GB of DDR2 memory and a 160GB Serial ATA hard drive. In these tests we found the real-world performance impact to be minimal between no encryption and full disk encryption. However, this system is much more powerful than any Intel Atom system.

For our tests today we had used the ASUS Eee PC 901 and tested it with Ubuntu 8.10 Alpha 4 with all development updates as of August 29. These installed updates include the switch to the Linux 2.6.27 kernel. We had run our select disk tests with an unencrypted LVM and then again with the full-disk LVM encryption. The tests used were run within the Phoronix Test Suite 1.2.0 Beta 3 release and included Bonnie++, Flexible IO Tester, ImageMagick compilation, Tandem XML, SQLite, GnuPG file encryption, and Sunflow Rendering System.

The ASUS Eee PC 901 consists of an Intel Atom N270 (1.60GHz) single-core processor, Intel 945GME Express Graphics, 1GB of DDR2 memory, and Intel UMA graphics with a 1024 x 600 display. The two solid-state disks are detected as a 16GB and 4GB ASUS-PHISON SSD drives.