Strategies for splitting load across varnish instances? And avoiding single-point-of-failure?
phk at phk.freebsd.dk
Sat Jan 16 19:44:02 CET 2010
In message <d002c4031001160929p1f688fc9mcc927dda2c684b86 at mail.gmail.com>, Micha
el Fischer writes:
>For instance sizes larger than 2, I think a consistent hash is needed.
> Otherwise, the overall hit ratio will fall dramatically upon failure of an
>instance as the requests are rerouted.
If you have perfect 1/3 splitting between 3 varnishes, having one die
will do bad things to your hitrate until the remaining two distribute
the load between them.
That's a matter of math, and has nothing to do with the hash algorithm.
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
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