David Dyer-Bennet wrote:
On 9/12/06, eric kustarz <[EMAIL PROTECTED]> wrote:
So it seems to me that having this feature per-file is really useful.
Say i have a presentation to give in Pleasanton, and the presentation
lives on my single-disk laptop - I want all the meta-data and the actual
presentation to be replicated. We already use ditto blocks for the
meta-data. Now we could have an extra copy of the actual data. When i
get back from the presentation i can turn off the extra copies.
Yes, you could do that.
*I* would make a copy on a CD, which I would carry in a separate case
from the laptop.
Do you backup the presentation to CD everytime you make an edit?
I think my presentation is a lot safer than your presentation.
I'm sure both of our presentations would be equally safe as we would
know not to have the only copy(ies) on our personage.
Similarly for your digital images example; I don't consider it safe
until I have two or more *independent* copies. Two copies on a single
hard drive doesn't come even close to passing the test for me; as many
people have pointed out, those tend to fail all at once. And I will
also point out that laptops get stolen a lot. And of course all the
accidents involving fumble-fingers, OS bugs, and driver bugs won't be
helped by the data duplication either. (Those will mostly be helped
by sensible use of snapshots, though, which is another argument for
ZFS on *any* disk you work on a lot.)
Well of course you would have a separate, independent copy if it really
mattered.
The more I look at it the more I think that a second copy on the same
disk doesn't protect against very much real-world risk. Am I wrong
here? Are partial(small) disk corruptions more common than I think?
I don't have a good statistical view of disk failures.
Well let's see - my friend accompanied me on a trip and saved her photos
daily onto her laptop. Near the end of the trip her hard drive started
having problems. The hard drive was not dead, as it was bootable and
you could access certain data. Upon returning home she was able to
retrieve some of her photos but not all. She would have been much
happier having ZFS + "copies".
And yes, you could backup to CD/DVD every night, but its a pain and
people don't do it (as much as they should).
Side note: it would have cost hundreds of dollars for data recovery to
have just the *possibility* to get the other photos.
eric
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