Re: Differential backup

On Apr 27, 2010, at 16:08 , Simon Riggs wrote:
> On Tue, 2010-04-27 at 08:59 -0500, Kevin Grittner wrote:
>> Why? I must be missing something, because my feeling is that if you
>> can't trust your OS to cover something like this, how can you trust
>> any application *running* under that OS to do it?
>
> Good questions. I'm exploring a perceived need.
>
> I don't think people want this because they think the OS is flaky. It's
> more about trusting all of the configurations of all of the filesystems
> in use. An explicit mechanism would be more verifiably accurate. It
> might just be about control and blame.

I believe a reason for people (including me) to not have 100% faith in file modification times are non-monotone system clocks. I've seen more than one system where a cron job running ntpdate every night was used as a poor man's replacement for ntpd...

So the real advantage of rolling our own solution is the ability to use LSNs instead of timestamps I'd say.

best regards,
Florian Pflug