On 28/09/09 02:10, Robert Heller wrote:
I don't really think external hard drives are that great considering they are just as reliable as internal hard drives which would be pointless as RAID1 should be reliable enough in that case.
The point to using an external hard drive is that unlike the internal one(s), the external one(s) would be 'idle' most of the time (only active during the actual backup process, which would be a once every n time units (once a day, once a week, whatever). Depending on the technology in use, 'inactive' can mean unmounted, sleep mode, powered off, disconnected, etc.
Right, and that means its running under different conditions to the internal hdd's - which in turn means that the failure pattern for this external disk will be very different to the ones that are internal.
I think its a given state that disks will fail, you just want to try and make some efforts to spread that failure rate around a bit so they dont all fail at the same time! And keeping a disk under different conditions, like in an external enclosure goes some way towards that.
also, I've noticed that some of these external disks actually fail more often than internal 24/7 types. Ok, I've not done any study on it or have a large sample - this opinion is based on personal experience and that of people around ( coworkers, friends, family, local lug speak ). So extremely unscientific :) Mostly resons blamed are that external disks tend to get knocked around a lot more - and also run a lot warmer than internal ones and are power cycled a lot more too.
- KB