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From Leif Hedstrom <zw...@apache.org>
Subject Re: Trafficserver startup.
Date Tue, 20 Mar 2012 19:06:28 GMT
On 3/20/12 12:48 PM, Van Doorn, Jan R wrote:
> Hi,
>
> When I startup trafficserver, I takes about 3-4 minutes for it to say 
> "NOTE: cache enabled". In that time, the cache is serving requests, but 
> it's not writing to the cache, the CPU usage is very high (E_NET threads), 
> and sometimes clients will hang when they try to get data from/through the 
> cache.
>
> Is this normal?  Should I wait with redirecting traffic to the cache until 
> i get this ""NOTE: cache enabled" message? I am using 3.0.2 on a pretty 
> beefy new box with ~11TB of cache over 14 spindles.
>


Probably as expected. 11TB, with the default settings of one directory entry 
(or "object") per 8,000 bytes means 1,511,828,488 entries. That's 1.5 
billion entries... It has to read and load all that information into memory 
before it can serve out of cache.

Is the expectation really to hold 1.5 billion entries in the cache ? If not, 
you should adjust the configuration accordingly. That will not only speed up 
startup times, but also reduce memory consumption (that 1.5B entries would 
consume a lot of RAM, like probably 20GB or so). So, if you set it to say 
64KB, you could hold "only"~ 400 million objects in the cache, but would 
reduce RAM and startup time by a factor of 4.

-- Leif


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