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On Sat, 29 Jun 2002, Daniel Burke wrote:
>
> That makes much more sense, thanks. I'd suggest
> clarifying the help for that entry in the kernel
> config... rereading it it still seems confusing even
> now that I know how to actually do it.
>
I forgot to mention that the chaining scheme is used in the hash table, I
think that this might confuse you. Just added that the input number is
limited from 8 to 20, in order to prevent this configuring problem from
happening again.
The help for IPVS connection hash table is as follows:
IPVS connection hash table size (the Nth power of 2)
CONFIG_IP_VS_TAB_BITS
The IPVS connection hash table uses the chaining scheme to handle
hash collisions. Using a big IPVS connection hash table will greatly
reduce conflicts when there are hundreds of thousands of connections
in the hash table.
Note the table size must be power of 2. The table size will be the
value of 2 to the your input number power. The number to choose is
from 8 to 20, the default number is 12, which means the table size
is 4096. Don't input the number too small, otherwise you will lose
performance on it. You can adapt the table size yourself, according
to your virtual server application. It is good to set the table size
not far less than the number of connections per second multiplying
average lasting time of connection in the table. For example, your
virtual server gets 200 connections per second, the connection lasts
for 200 seconds in average in the connection table, the table size
should be not far less than 200x200, it is good to set the table
size 32768 (2**15).
Another note that each connection occupies 128 bytes effectively and
each hash entry uses 8 bytes, so you can estimate how much memory is
needed for your box.
If there is still anything confusing, please point it out.
Thanks,
Wensong
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