admin at lctn.org wrote: > I have a box with a single drive running Linux apps. Is there a way to > mirror the drive now, or can that only be done during the install process? > i think the question you have to answer is - do you want auto recovery, or can you live with a manual recovery. if you want auto recovery - then i would suggest creating a RAID-1 mirror of the main drive. to do this is straight forward but does require many steps. add new disk (B) to system. create/build raid 1 device /dev/md0 on new disk (B) with missing device. this will build up the raid-1 device in a degraded mode. format new raid-1 device and then copy all data from old disk (A) to new raid-1 device. once the data has been copied, join the old disk (A) to raid-1 device restoring it from degraded-mode. i would only do this if you have a really good backup, or if you can actually set disk (A) aside, and build up the raid 1 device with 2 new drives. disks are really cheap theses days, so i would buy 2 new drives, build up the raid-1 device and copy the data over. this of course is a simple explanation for what you would need to do, and depending on your partition layout and the like, it may be just as simple buy 2 new disks, install from scratch onto the new raid-1 device, and then copy over your application data from your original drive. if not - then rsync or another file level utility can do the trick - just remember that it your mirrored data is only as new as the last time you run the rsync utility. this can be cron'ed.