I recently received a dozens of AH00708: errors in my logs. Example: > (2)No such file or directory: AH00708: Cannot open data file /var/cache/apache2/mod_cache_disk/Y/Z/CLVvRR_4nNWabdUv_5wA.header.vary/B/z/bK@xxxxxxxxxxxxxxxxxxxxxx Said file does not exist, only does the corresponding .header file. The cache is 455 MB, I don't know what could have happened and I activated debug loglevel for mod_cache_disk for next days in order to understand why the data file isn't created. ... but, looking at the header file I found the following line rather strange: [...] > Content-Encoding: gzip > Vary: User-Agent, User-Agent, User-Agent, User-Agent > Accept-Ranges: byte [...] - I've no occurrence of Vary either in /var/www nor in /etc/apache2 - searching google retrieved a couple of similar results of this Vary: string The origin is probably the BrowserMatch directive which, by default are enabled in Debian's mods-available/setenvif.conf. (and mod_ssl depends upon mod_setenvif) This is how I realized that the cache coupled to setenvif in it's default configuration was *very* inefficient (disk-space). `Vary: User-Agent` is something we would rather avoid given the ridiculously huge number of combination for this string nowadays. >From the last quick grep' I had 325 of them what could reduce my cache's size to a dozens of MB and increase proportionally it's efficiency. First, not really a question, but a couple of suggestions: - BrowserMatch should not blindly add to the Vary header but addifnotexist (it's part of the mod_headers possibility in Apache 2.4 series isn't?) - mod_cache_disk documentation could state whether this duplication hurts or not - the default setenvif.conf may avoid use of "exotic"/"rare" default BrowserMatch directives in case of <IfModule mod_cache.c> ... but then, following the objective to avoid a Vary: User-Agent, I found that I had two other BrowserMatch in default-ssl.conf. The second one about MSIE 7 to 10, in order to set ssl-unclean-shutdown. - I didn't find where is documented what this variable does internally - I guess this variable only affects mod_ssl behavior but nothing about request header/data If the above is right, then is it pertinent with discard^W Vary: User-Agent if the content can't change according to the User-Agent. Maybe BrowserMatch could be more flexible about that. Anyway, I commented these two mod_ssl BrowserMatch directives (in case I would not care about broken? MSIE behaviors), but I'm still Vary'ing: User-Agent. I commented the ultimate SetEnvIfExpr my configuration contained (unrelated to browsers anyway) and egrep -ri '(Browser|SetEnvIf)' but still... Vary: User-Agent https://github.com/apache/httpd/search?l=c&q=User-Agent&type=Code&utf8=%E2%9C%93 didn't brought up another clear source for this. Any hint about where this Vary's value could come from? thank you --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscribe@xxxxxxxxxxxxxxxx For additional commands, e-mail: users-help@xxxxxxxxxxxxxxxx
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