I have used squid for last 2 years and i wanted to move to varnish mainly because of the performance.
I have the following observations/questions in varnish 2.0.4. kindly help with my questions. Regards Ganesh 1. varnish doesn't send IMS request, when the object expires. detail: When a object is set with maxage=1 min, after 1 min, varnsish calls vcl_timeout which calls vcl_discard and the object is discarded. any request after 1 min ( a normal GET request ), varnish downloads the complete object from origin server. Squid sends If-Modified-Since, If-None-Match requests to origin, which results in 304 response, thereby origin server is not loaded. Question: could varnish just mark the object expired and on the next GET request to the object, send a If-Modified-Since request to origin server? if its not in architecture, can we do it with vcl_xxx routines to achieve the same? let me knw how to achieve that? -------------------------------- 2. Varnish cache is not persistent. detail: when i stop and restart varnish, all the objects in the cache are lost. Varnish has to rebuild the cache from beginning, which load the origin server. I used mmap storage option, with the assumption that it will have a backup copy of cached objects. Question: Is my observation true in 2.0.4? If so, is there any plans to include cache persistence in future releases? ----------------------------------------------------- 3. mmap storage : max i can configure is 340 GB. detail:: I was able to use only 340 GB of cache. any size after this, i would get error. child (25790) Started Pushing vcls failed: dlopen(./vcl.1P9zoqAU.so): ./vcl.1P9zoqAU.so: failed to map segment from shared object: Cannot allocate memory currently my system has 1.5 TB of storage. squid used the entire storage. Question: Why there is a limitation on cache storage? ---------------------------------------------------------- 4. I tried malloc storage option. Question: i have system of 32 GB physical ram and my swap storage is 65 GB. harddisk storage - 1.5 TB ( distribued in 5 cache directoreys /cach0,.../cache1 ). What is the best optimal malloc storage i can use to achive greater performance? -s malloc, [ size ] ??? ---------------------------------------------- 5. what is the difference between using malloc or mmap? Help me to move onto varnish world and convince others in my team. Ganesh _______________________________________________ varnish-misc mailing list [email protected] http://projects.linpro.no/mailman/listinfo/varnish-misc
