[squid-users] analyzing cache in and out files

[Matus UHLAR - fantomas]

>Em 30/09/15 04:13, Matus UHLAR - fantomas escreveu:
>>
>>the problem was iirc in caching partial objects
>>http://wiki.squid-cache.org/Features/PartialResponsesCaching
>>
>>that problem could be avoided with properly setting range_offset_limit
>>http://www.squid-cache.org/Doc/config/range_offset_limit/
>>but that also means that whole files instead of just their parts are
>>fetched.
>>
>>it's quite possible that microsoft changed the windows updates to 
>>be smaller
>>files, but I don't know anything about this, so I wonder if you really do
>>cache windows updates, and how does the caching work related to 
>>informations
>>above...

On 30.09.15 11:08, Leonardo Rodrigues wrote:
>    yes, i'm definitely caching windows update files !!
>
>[root at firewall ~]# cd /var/squid/
>[root at firewall squid]# for i in `find . -type f`; do strings $i | 
>head -3 | grep "http://"; done  | grep windowsupdate | wc -l
>824
>
>    and yes, i had to configure range_offset_limit:
>
>range_offset_limit 500 MB updates
>minimum_object_size 500 KB
>maximum_object_size 500 MB
>quick_abort_min -1
>
>(being 'updates' the ACL with the URLs to be cached, basically 
>windowsupdate and avast definition updates - the second one required 
>further tweaks with storeid_rewrite for the CDN URLs)

of course... BTW at one of my customers I noticed downloading the same HUGE
files multiple times a day from a few machines - comodo antivirus.
Some of updates have wven worse design...

>    from access.log, i see a lot of TCP_HIT/206 (and just a few 
>TCP_HIT/200), so it seems squid is able to get the fully cached file 
>and provide the smaller pieces requested:
>
>[root at firewall squid]# grep "TCP_HIT/" access.log | grep 
>windowsupdate | wc -l
>9860
>[root at firewall squid]# bzcat access.log.20150927.bz2 | grep 
>"TCP_HIT/" | grep windowsupdate | wc -l
>38584

can you provide maximum size of those files?

>    having squid to download the WHOLE file at the very first request 
>(even a partial request) may be bad, but considering it will be used 
>later to provide the data for other requests, even partial ones, make 
>things a little better.
>
>(this windowsupdate caching is running just for a few weeks, i expect 
>HITs to grow a little more)

watching this and providing information would be nice from you...

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Matus UHLAR - fantomas, uhlar at fantomas.sk ; http://www.fantomas.sk/
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