Re: Accelerator Cluster

["Mar Matthias Darin" <BDarin@xxxxxxxxxx>]

Hello, 

Jerry Thomas writes: 

> I am running a cluster of squid 2.5 servers to accelerate many domains
> and everything is working very well. 
>
> I am currently going direct to the origin servers on cache misses. 
>
> Will there be performance gains if I add the other squid servers as
> cache peers or will the endusers perceive latency while the squid checks
> its peers versus going direct. 

I run a small LAN with similar issues.  I have 4 desktops that run squid and 
check the other 3 before hitting the gateway which also runs Squid.  I was 
having latency issues until I had all my users run a proxy.pac with the 
following: 

function FindProxyForURL(url, host)
{
  var hash=0;

  if((position("127.0.0.1",url)>-1)
  || (position(".lan",url)>-1))
    return "DIRECT";

  hash=URLhash(url);

  switch(hash)
    {
      case 0:
        return "PROXY 10.0.0.10:3177; PROXY 10.0.0.11:3177; PROXY 
10.0.0.12:3177; PROXY 10.0.0.13:3177; DIRECT";
        break;
      case 1:
        return "PROXY 10.0.0.11:3177; PROXY 10.0.0.12:3177; PROXY 
10.0.0.13:3177;  PROXY 10.0.0.10:3177; DIRECT";
        break;
      case 2:
        return "PROXY 10.0.0.12:3177; PROXY 10.0.0.13:3177;  PROXY 
10.0.0.10:3177; PROXY 10.0.0.11:3177; DIRECT";
        break;
      case 3:
        return "PROXY 10.0.0.13:3177;  PROXY 10.0.0.10:3177; PROXY 
10.0.0.11:3177; PROXY 10.0.0.12:3177; DIRECT";
        break;
    }
}

function URLhash(name)
{
  var now = new Date();

  var cnt=0;
  var hash=0;

  var str=name.toLowerCase(name);
  for(var i=0;i < str.length ; i++)
    {
      var ch=(str.substring(i,i+1));
      var n=char2num(ch);
      cnt=cnt+n;
    }

  hash=(Math.floor(now.getSeconds()+cnt)%4);

  return(hash);
}

function char2num(ch)
{
  var symbols=" !\"#$%&'()*+'-./0123456789:;<=>?@";
  var loAZ="abcdefghijklmnopqrstuvwxyz";
  var loc;

  symbols+=loAZ.toUpperCase();
  symbols+="[\\]^_`";
  symbols+=loAZ;
  symbols+="{|}~";

  loc=symbols.indexOf(ch);
  if(loc>-1)
    return(32+loc);
  else
    return(0);
}

function position(srch,name)
{
  var l=srch.length;
  var t=name.length;
  var e=t-l+1;
  var done=-1;

  for(var i=0;i<e && done<0;i++)
    {
      var sub=name.substring(i,i+l);
      if(sub==srch)
        done=i;
    }
  return(done);
}


This gives me good results even under extremely high load...

Attachment: pgpAuEqIT0dyC.pgp
Description: PGP signature