IMS: grace & keep

Poul-Henning Kamp phk at phk.freebsd.dk
Sun Mar 13 09:51:24 CET 2011


In message <4D7BABBF.7030106 at uplex.de>, Geoff Simmons writes:

>So: if TTL has elapsed, but Varnish finds an object in grace, and
>decides as it does now to serve it from cache, then it does so;
>otherwise Varnish uses it to attempt the conditional request (if the
>object has the headers for it).

Well, this sort of goes to the max(grace,keep) vs (grace+keep) issue.

If we make it max(grace,keep), then only keep should be considered
for IMS, and the two timers are 100% independent.

If we make it (grace+keep) they act in tandem and any object in grace
is automatically subject to IMS and you can not totally disable
IMS on an object.

Which is more intuitive ?

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.




More information about the varnish-dev mailing list