F5 has some documents on how to implement consisent hashes in bigipirules (tcl),but i wound up writing a custom one for use in front of our squidsthat only does onechecksum per request, as opposed to one per squid in the pool, to avoid wastingcpu cycles on the LB. it uses a precomputed table for the nodes, but doesn't need to be recomputedwhen you add/remove a few, they just fit in between the others. i'lltry to finishthe writeup and submit it to devcentral soon. -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 Garc燰 <malevo@xxxxxxxxx> 說：> >> >> 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! 網上安全攻略，教你如何防範黑客!> >> 請前往http://hk.promo.yahoo.com/security/index.html> >> 了解更多。> >>>> >>> >> >> >> > Yahoo! 網上安全攻略，教你如何防範黑客! 請前往http://hk> > .promo.yahoo.com/security/index.html 了解更多。>> --> Mark Nottingham mnot@xxxxxxxxxxxxx>>>
