Hi all,
I'm new to lighttpd and mod_cache. Here I met some troubles. Could any
one help me?
I have a image server who has 2G memory, without memory cache, vmstat
looks like this:
procs -----------memory---------- ---swap-- -----io---- --system--
-----cpu------
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us
sy id wa st
 1  0    112  11016  80104 1638712    0    0    38    61    0   13  0
2 95  3  0
 1  1    112   9988  80136 1639872    0    0   872  1144 8126  225  4
8 70 17  0
 0  1    112  10300  80160 1639848    0    0    80  6868 3962  102  0
2 74 24  0
 0  1    112   9804  80160 1639980    0    0     0     0 1790  161  0
1 75 24  0

As you can see, more then 20% CPU time is spent on waiting for IO. To
speed it up, I used mod_cache. These are what I have done:
1. download lighttpd-1.4.23.modcache.v.1.8.0.tar.gz, and configure
with the following command:
./configure --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/
info --enable-shared --enable-threads=posix --enable-checking=release
--with-system-zlib --enable-lfs --with-openssl --with-mysql --with-
zlib --with-memcache --enable-__cxa_atexit --disable-libunwind-
exceptions --enable-libgcj-multifile --enable-languages=c,c++,objc,obj-
c++,java,fortran,ada --enable-java-awt=gtk --disable-dssi --enable-
plugin --with-java-home=/usr/lib/jvm/java-1.4.2-gcj-1.4.2.0/jre --with-
cpu=generic --host=x86_64-redhat-linux

Then make and install. Everything is successful. Then I modified
lighttpd.conf and append following lines:
cache.enable = "enable"
cache.max-memory-size = 1024
and of course enabled mod_cache at the beginning of lighttpd.conf
server.modules              = (
                                "mod_cache",
                                "mod_rewrite",
...
However, after all this, vmstat result still looks the same. No memory
is spent caching anything, and no doubt there is a lot of network
traffic. I think I must have missed something. Can anyone help me?
Thank you!

full docs at http://www.linux.com.cn/modcache/

you need to use cache.refresh-pattern to enable memory usage. for example:

cache.refresh-pattern = (
   "\.(?i)(jpg|bmp|jpeg|gif|png)$" => "2880 use-memory"

)

Great. It reduces about 10% CPU usage. Thank you
By the way, I still have another problem. Does lighttpd use only 1 CPU?
Now I can see only 1 CPU is used up to 50%, while other 3 CPUs are
almost not used at all. Is this the way how lighttpd works or should do
anything else for load balance?

Regards,
YX

On 2009年10月22日 09:06, shellcode wrote:

you can use server.max-worker = 4.

but keep in mind that modcache's memory cache don't share across lighttpd.
you got server.max-worker * cache.max-memory-size usage.

for example:
server.max-worker = 4
cache.max-memory-size = 256

4 lighttpd's modcache will eat up to 4 * 256M = 1G memory

Thank you so much.
About memory cache I still got a question. Now in my lighttpd.conf I got
following lines:
.....
server.modules                 = (
         "mod_indexfile",
         "mod_cache",
         "mod_rewrite",
         "mod_access",
         "mod_expire",
         "mod_accesslog",
         "mod_dirlisting",
         "mod_staticfile",
         # 8
     )
....
# for cache module
cache.enable = "enable"
cache.max-memory-size = 1024
cache.refresh-pattern = ("\.(?i)(jpg|jpeg|gif|png)$" => "21600 use-memory")

But after one day's observing, I found that free memory doesn't reduce
at all. It seems nothing's cached. This is the vmstat I get:
procs -----------memory---------- ---swap-- -----io---- --system--
-----cpu------
  r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy
id wa st
  0  0    112  10148  81468 1673776    0    0    51   155   12   16  1  
4 90  5  0
  0  3    112  10032  81476 1674104    0    0   252     0 4036 1059  1  
5 78 16  0
  0  4    112   9608  81496 1674400    0    0   228   404 4217 1583  2  
6 78 14  0
  0  3    112  10500  81476 1673464    0    0   476  4776 4079  709  2  
4 69 25  0
  0  0    112   9828  81488 1673752    0    0   288     0 4173 1203  2  
6 72 20  0

I also tried not to use "use-memory" option, and set a cache.bases for
file cache. but still, I found nothing there. It seems mod_cache is not
activated. Maybe I'm still missing something?
PS: I'm using the package lighttpd-1.4.23.modcache.v.1.8.0.tar.gz

Regards,
YX

you can read http://blog.quehy.com/archives/216.html, it's explain some
cases that modcache don't cache