[TUHS] Irwin 285

Larry McVoy lm at bitmover.com
Sat Jan 23 01:38:25 AEST 2010

On Fri, Jan 22, 2010 at 11:15:57AM +0100, Jochen Kunz wrote:
> On Fri, 22 Jan 2010 10:34:09 +0100
> Wilko Bulte <wb at freebie.xs4all.nl> wrote:
> > recoverable read error rate I presume.
> No. NON-recoverable read error rate: 1 per 10^14 bits.
> And this is for light desktop use. Heavy IO on the disk may increase
> failure rate. At least this is written in the technical data sheet of
> the drive. WD drives are not that much better: 1 per 10^15 bits.

You guys are funny.  I've been doing backups for at least 15 years
and I can tell you story after story about tape failures that
happened to me personally (anyone remember the lovely exabyte 8200,
"fondly" remembered as the write-only device?).  On the other hand,
disks work pretty well and when they fail, they fail in little 
chunks and you can almost always get the rest of the data.

For the data I really care about, our digital photo collection, it's
all stored in BitKeeper's so-called binary asset management (BAM).
All the data is CRC-ed, it's all replicated, and if anything goes
bad the bad data can easily be replaced from any of the other
(populated) replicas.  I periodically run "bk bam check" which 
goes through all the data and checks the crc's and have yet to
see an error.  Been doing that for years.

Tape.  Bah.  You can keep it, I'm OK with disk.
Larry McVoy                lm at bitmover.com           http://www.bitkeeper.com
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