[OpenAFS-devel] Re: The ihandle sync thing

[Andrew Deason]

On Thu, 28 Mar 2013 19:02:38 +0100
Stephan Wiesand <stephan.wiesand@desy.de> wrote:

> > I understand the current use of the ihandle cache for this is
> > problematic, but that is not an excuse to never sync.
> 
> To my understanding, ripping out the current implementation of
> background syncs may cause somewhat more damage to files written to
> during the last O(10s) before in the case of a server crash - it's not
> prevented completely either way.

I think that's a little backwards, if I'm reading that correctly. For
files written within the last 10 seconds (approximately), the behavior
is definitely the same whether or not it's ripped out.

The pro-background-sync argument is that beyond those 10 seconds is when
things are different. That is, beyond 10 seconds, the files are 'safe'
with the background sync in, and with background sync ripped out, they
are not 'safe' until some unknown/unbounded point in the future.

The anti-background-sync argument is that the after-10-seconds-pass case
is very similar, or exactly the same, whether or not the background sync
thread is ripped out. (And of course, the background sync thread has
problems and destroys data and is evil, etc, etc :)

-- 
Andrew Deason
adeason@sinenomine.net