Re: backup archive format saved to disk
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On 12/07/06 08:16, Douglas Tutty wrote:
> On Wed, Dec 06, 2006 at 09:02:37PM -0600, Reid Priedhorsky wrote:
[snip]
> Apparently, hard disks use FEC themselves so that they either can fix
> the data or there is too much damage and the drive is inaccessible. It
> seems to be an all-or-nothing propositition. If someone has experience
> of FEC drive failures that refutes this I'd be very interested.
>
> The only disk failures I have experienced are on older drives without
> FEC that for a given sector return an error about bad CRC but one can
> carry on and read the rest of the disk. It was from this perspective
> that I proposed the question that led to this thread.
>
> If drives are atomic in this way, it seems that the only way to achieve
But I don't think they are. Depending on the problem, drives that
go bad can spit out scary messages to syslog for weeks before they die.
Of course, it all depends on the problem. If the drive electronics
or mechanics die, you'll have to send it off to a data recovery company.
Drives just have more that can go wrong: electronics, mechanicals
and media. Tapes just have, well, tape: the media. If a drive goes
bad, you call the vendor and they come out and repair it (most
likely via a jerk-and-switch).
However, the cost of a tape drive plus support contract might
outweigh the cost of sending a dud HDD to a data recovery company.
BTW, how much data do you have to archive, and at what frequency?
One time only, or weekly, monthly, quarterly? Is this personal
data, or company data?
> redundancy is through multiple copies (either manually done or via
But you should do that anyway. How important *is* your data.
> raid1).
RAID is *not* for archives!!!
> I'm still hoping that someone who knows how linux software raid work can
> tell me how it decides that a drive has failed. This question was posed
> in a thread about raid1 internals.
- --
Ron Johnson, Jr.
Jefferson LA USA
Is "common sense" really valid?
For example, it is "common sense" to white-power racists that
whites are superior to blacks, and that those with brown skins
are mud people.
However, that "common sense" is obviously wrong.
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