> F5 has some documents on how to implement consisent hashes in bigip > irules (tcl), > but i wound up writing a custom one for use in front of our squids > that only does one > checksum per request, as opposed to one per squid in the pool, to avoid > wasting > cpu cycles on the LB. > > it uses a precomputed table for the nodes, but doesn't need to be > recomputed > when you add/remove a few, they just fit in between the others. i'll > try to finish > the writeup and submit it to devcentral soon. If its good code, as useful as it seems, and under the GPLv2+ we may be interested in bundling it with future squid as a helper tool. Amos > > -neil > > 2008/3/10 Mark Nottingham <mnot@xxxxxxxxxxxxx>: >> This is the problem that CARP and other consistent hashing approaches >> are supposed to solve. Unfortunately, the Squid in the front will >> often be a bottleneck... >> >> Cheers, >> >> >> >> >> On 07/03/2008, at 1:43 PM, Siu Kin LAM wrote: >> >> > Hi Pablo >> > >> > Actually, it is my case. >> > The URL-hash is helpful to reduce the duplicated >> > objects. However, once adding/removing squid server, >> > load balancer needs to re-calculate the hash of URL >> > which cause lot of TCP_MISS in squid server at the >> > inital stage. >> > >> > Do you have same experience ? >> > >> > Thanks >> > >> > >> > --- Pablo García <malevo@xxxxxxxxx> »¡¡G >> > >> >> I dealt with the same problem using a load balancer >> >> in front of the >> >> cache farm, using a URL-HASH algorithm to send the >> >> same url to the >> >> same cache every time. It works great, and also >> >> increases the hit >> >> ratio a lot. >> >> >> >> Regards, Pablo >> >> >> >> 2008/3/6 Siu Kin LAM <sklam2005@xxxxxxxxxxxx>: >> >>> Dear all >> >>> >> >>> At this moment, I have several squid servers for >> >> http >> >>> caching. Many duplicated objects have been found >> >> in >> >>> different servers. I would minimize to data >> >> storage >> >>> by installing a large centralized storage and the >> >>> squid servers mount to the storage as data disk. >> >>> >> >>> Have anyone tried this before? >> >>> >> >>> thanks a lot >> >>> >> >>> >> >>> Yahoo! ºô¤W¦w¥þ§ð²¤¡A±Ð§A¦p¦ó¨¾½d¶Â«È! >> >> ½Ð«e©¹http://hk.promo.yahoo.com/security/index.html >> >> ¤F¸Ñ§ó¦h¡C >> >>> >> >> >> > >> > >> > >> > Yahoo! ºô¤W¦w¥þ§ð²¤¡A±Ð§A¦p¦ó¨¾½d¶Â«È! ½Ð«e©¹http://hk >> > .promo.yahoo.com/security/index.html ¤F¸Ñ§ó¦h¡C >> >> -- >> Mark Nottingham mnot@xxxxxxxxxxxxx >> >> >> >
