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
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