[SSSD] NSS: disable midpoint refresh for netgroups if ptask refresh is enabled

Jakub Hrozek jhrozek at redhat.com
Thu Apr 17 08:21:04 UTC 2014


On Wed, Apr 16, 2014 at 03:04:16PM +0200, Pavel Reichl wrote:
> On Mon, 2014-04-07 at 19:07 +0200, Jakub Hrozek wrote:
> [snip]
> > btw can we get into this situation where the refresh is on but a netgroup
> > is expired even without misconfiguration? For instance if a netgroup was
> > saved to the cache right before the backend was about to schedule the
> > periodic task, then before the next task the netgroup was requested and
> > already expired? 
> 
> I see your concern now. But I think that the most critical moment would
> be if netgroup was saved to the cache right *after* the periodic task
> being scheduled. That could lead to netgroup not being refreshed for
> almost 2*refresh_expired_interval and thus being stale for 1/2
> entry_cache_timeout (~2700 seconds) if default values were used*.

Stale records, if they are in the range of minutes are OK in this case,
I think. The caching comes at a cost.

What would not be so ideal is if the next getnetgrent() would cause the
whole hierarchy to be downloaded again.



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