slave zone files unreadable

[Barry Margolin]

In article <mailman.559.1405100971.26362.bind-users at lists.isc.org>,
 Evan Hunt <each at isc.org> wrote:

> On Fri, Jul 11, 2014 at 12:12:22PM -0400, John Wobus wrote:
> > In cases analogous to this, software often saves both
> > text and binary, and when initializing, uses mtime to
> > decide whether it can safely use the binary.  Some resources
> > are spent storing the extra file and admins have yet
> > another way to screw things up, but the strategy
> > does have benefits.
> 
> You can't always rely on mtime for that.  The disk may have been hit by
> cosmic rays since last time you read the file, and mtime hasn't changed but
> the file is different anyway.

BIND already assumes mtime is reliable -- if you do "ndc reload", it 
only reloads zone files whose mtimes are newer than when the zone was 
previously loaded.

If you're worried about cosmic rays, you can't rely on ANYTHING on the 
disk. Why would you consider the file contents to be reasonable if they 
could change spontaneously.

Anyway, don't all modern disks have ECC codes in them? These will detect 
and correct bit flips in the mtime just as well as the contents. If you 
want extra safety, use RAID.

-- 
Barry Margolin
Arlington, MA