On Tuesday, January 1, 2002, at 05:55 PM, Jason Lim wrote:
You might say "tape backup"... but keep in mind that it doesn't offer a "plug n play" solution if a server goes down. With the above method, adead server could be brought to life in a minute or so (literally) ratherthan half an hour... an hour... or more.
It occours to me that in most cases, recovery from a catostrophic failure is not going to be as easy as plug and play. Let's take some common situations where we need to recover a system.
Virus -The way I traditionaly deal with a virus, is to never have it touch my system. As a system admin it is my job to keep viruses from hitting machines in the first place, not clean them up once they arrive. Cleaning up is the mentality of the Microsoft security world, and I refuse to accept such poluted doctrine. However, I do have a contingency plan should I miss a virus. I have a master OS image burnt onto a disk, and each of my systems make a backup of their data nightly (simple tar). The backups rotate and are incrimental, so I can restore data to the current date, masking out any infected paths. This, however, is not a plug and play solution, it requires manual control.
Hardware failure-I run arround and sceam alot. This kind of failure is mostly luck of the draw, but I try to follow the same strategy as above.
Hacker-If they wipe the disk, then the OS image and data backup will work nicely. If they do something else, then I wipe the disk myself (no backdoors that way), and recover.
In none of these situations do I see any value in making a replica of a tainted or damaged disk every 12 hours.