On 27/10/2015 1:00 a.m., joe wrote: > regarding range_offset_limit no matter what i do idm or any download > manager not working correctly > > try to download using idm and it start downloading one file suppose to start > downloading multiple of chunk range setting idm to download 16 chunk range > at the same time only one start downloading once it finish downloading first > part it start the second one after the other and that is bad wen i pause or > stop then resume downloading all the chunk range start normal downloading > same time that is normal behavior > > only new file at the start it download one chunk insted of multiple until i > hit stop then resume so squid respond only to one range wen the new file > start > hitting stop then resume squid working good with all the range > downloading same time > and that big time issue since most of my customer using idm or any download > manager file not cached > i duno if i explain it right but over squid supost to respond to all the > range as idm rquest at the begining of the download if i bypass squid idm > work correctly Sounds right. idm is sending multiple parallel Range requests. Essentially trying to fake faster downloads by forcing as many resources to be consumed by the one user as possible. This is a very unfriendly client behaviour - stealing bandwidth and resources from other users who need to share them, at all network layers from the CPE device outwards to the server itself. Squid is an optimizing proxy. Parts of its design is to baulk that type of behaviour and make the network operate better for all. In particular it optimizes bandwidth consumption when you set range_offset_limit by fetching the entire object from the beginning of the download so that it can cache and server followup requests from the cache without consuming any server-facing resources at all regardless of number of users wanting that URL. If you dont use range_offset_limit then all fetches made by idm are Range request and cannot be cached to improve the experience for other clients needing the same URL/download. Each and every time a new object gets fetched, but in small pieces and hogging some of the potentially limited upstream bandwidth by the user with idm. When range_offset_limit is configured... * idm has made 5 Range requests in parallel. What that means is that it has sent 5x requests to Squid for the same object. But not the same data out of it, which makes them each a unique fetch. So... Squid starts fetching 5x downloads of the file (ouch, you can enable collapsed_forwarding to reduce that). Squid quickly reaches the start of the Range connection #1 requested and starts delivering it. BUT, it has not reached the download positions connection #2, #3, #4, #5 requested. All idm can see is connection #1 receiving data and the rest waiting. Then at the end of #1 connection Range Squid also hits the point where it has received the start of connection #2's Range and starts serving that up. Meanwhile connection #3, #4, #5 have not yet been reached, and so it continues until all the Ranges have been fetched and delivered or idm goes away. When using a proxy tools like idm are useless. Their abusive "optimizations" do more harm than good when they do "work". Amos _______________________________________________ squid-users mailing list squid-users@xxxxxxxxxxxxxxxxxxxxx http://lists.squid-cache.org/listinfo/squid-users
