Booting from USB Pen Drive

There are several Linux distributions that can fit onto a USB storage device and allow systems to boot directly from them. In fact, John Hearns pointed out that he has routinely booted systems from a USB memory stick that had StressLinux loaded in it.

Jim Lux also pointed out that there are simple IDE-to-CF (CF=Compact Flash) adapters that allow you to use CF cards as though they are disks. In a later post, Jim also pointed out how nice it could be to boot a diskless cluster node from a CF card using the adapter. This capability would help improve reliability (no moving parts) and reduce heat generation inside a node. Jim's intent is to use these kinds of devices on nodes that only have a wireless network (he doesn't want to ship a kernel and associated parts over a wireless network because of the low bandwidth). Andy Cater reminded everyone that Compact Flash has a number of limited rewrites, so perhaps using the CF card only for the read-only portions of the operating system and a small ramdisk for the portions that readily change (e.g. /var and /tmp).

Solid-state storage is fast becoming very inexpensive thanks to commodity uses (cameras, MP3 players, cell phones, etc.). These devices offer increased reliability and lower power usage and heat generation compared to hard drives. However, they are more expensive and slower (perhaps not an issue for read-only file systems) than hard drives. Overall, sold-state storage has much to offer and may be very useful for clusters.

This article was originally published in ClusterWorld Magazine. It has been updated and formated for the web. If you want to read more about HPC clusters and Linux you may wish to visit Linux Magazine.

Jeff Layton has been a cluster enthusiast since 1997 and spends far too much time reading mailing lists. He occasionally finds time to perform experiments on clusters in his basement.He also has a Ph. D. in Aeronautical and Astronautical Engineering and he's not afraid to use it.