On Tue, Aug 23, 2011 at 9:01 AM, Amos Jeffries <squid3@xxxxxxxxxxxxx> wrote: > On 24/08/11 00:47, Carlos Manuel Trepeu Pupo wrote: >> >> 2011/8/23 Amos Jeffries<squid3@xxxxxxxxxxxxx>: >>> >>> On 23/08/11 21:37, Matus UHLAR - fantomas wrote: >>>> >>>> On 16.08.11 16:54, Carlos Manuel Trepeu Pupo wrote: >>>>> >>>>> I want to make Common Address Redundancy Protocol or CARP with two >>>>> squid 3.0 STABLE10 that I have, but here I found this question: >>>> >>>> the CARP that squid supports is the "Cache Array Routing Protocol" >>>> http://en.wikipedia.org/wiki/Cache_Array_Routing_Protocol >>>> >>>> - this is something different than "Common Address Redundancy Protocol" >>>> http://en.wikipedia.org/wiki/Common_Address_Redundancy_Protocol >>> >>> Well, technically Squid supports both. Though we generally don't use the >>> term CARP to talk about the OS addressing algorithms. HA, LVS or NonStop >>> are >>> usually mentioned directly. >> >> Thanks for the tips, from now I will be careful with the term. >> >>> >>>> >>>>> If the main Squid with 40 GB of cache shutdown for any reason, then >>>>> the 2nd squid will start up but without any cache. >>>>> >>>>> There is any way to synchronize the both cache, so when this happen >>>>> the 2nd one start with all the cache ? >>>> >>>> You would need something that would synchronize squid's caches, >>>> otherwise it would eat two times the bandwidth. >>> >>> Seconded. >>> >>> If the second Squid is not running until the event the cache can be >>> safely >>> mirrored. Though that method will cause a slow DIRTY startup rather than >>> a >>> fast not-swap. On 40GB it could be very slow, and maybe worse than an >>> empty >>> cache. >>> >>> NP: the traffic spike from an empty cache decreases in exponential >>> proportion to the hit ratio of the traffic. From a spike peak equal to >>> the >>> internal bandwidth rate. >>> >>> PS. I have a feeling you might have some graphs to demonstrate that >>> spike >>> effect Carlos. Would you be able to share the images and numeric details? >>> I'm looking for details to update the 2002 documentation. >> >> Thanks to everyone, you guys always helping me !! Now I have a few >> problem with Debian and LVM, until I solve it I can't do it anything. >> But here another idea: >> >> I put the two squid in cascade and the Master (HA) make the petitions >> first to the second squid and if it down go directly to Internet. The >> both squid will cache all the contents, so will be duplicate the >> contents, but if someone go down, the other one will respond with all >> the content cached. >> >> It look like this: >> >> client ---> Server1 ---> Server2 ---> Internet (server1 and server2 >> will cache all) >> Server1 down >> client ---> Server2 ---> Internet (server2 will cache all) >> Server2 down >> client ---> Server1 ---> Internet (server2 will cache all) >> >> What do you think ? > > Looks good. > > Check your cache_peer directives connect-fail-limit=N values. It affects > whether and how much breakage a clients sees when Server2 goes down. If that > option is available on your Server1 squid, you want it set relatively low, > but not so low that random failures disconnect them. > > background-ping option is also useful for recovery once Server2 comes back > up. > > Amos > -- > Please be using > Current Stable Squid 2.7.STABLE9 or 3.1.14 > Beta testers wanted for 3.2.0.10 > Everything it's working fine !! Until now they are still in LAB mode, but with excellent results in tests. Now I would like to improve the mechanism to HA of my servers. Any other idea how to improve the work that I made until now. (I just make squid with UCARP in Debian)
