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From "pqf" <...@mailtech.cn>
Subject Re: mod_fcgid: different instances of the same program
Date Tue, 10 Nov 2009 01:28:43 GMT
Hi,
   Yes, mod_fcgid search process node base on file's inode and deviceid(plus share_group_id,
virtual host name). The goal is to create as less process as possible. Some administrators
like the idea that all virtual hosts share one PHP process pool. (But some other don't, they
can turn that off anyway. This is what share_group_id for in the first place, administrator
can make who share who's process pool)
   But the document should provide more detail about it, I missed that part in my old documents.
I am sure some native English speekers will modify the documents soon.

Thanks


From: Danny Sadinoff 
Sent: Tuesday, November 10, 2009 6:16 AM
To: dev@httpd.apache.org 
Subject: mod_fcgid: different instances of the same program


Here are two details of mod_fcgid process management that I've just
learned after a long debug session and squinting at the mod_fcgid
code.

1) symlinks & you.
It seems that mod_fcgid identifies fcgid programs by inode and device,
not by filename.  So two fcgid programs invoked by the webserver
along different paths will be counted as the same if the two paths are
hardlinks or softlinks to each other.

2) Virtual hosts
The above item holds true even across virtual hosts.   So while
it's possible to adjust the FcgidInitialEnv items on a per-vhost
basis, this is a recipe for disaster if two vhosts point at the same
fcgi executable, because the resulting processes with potentially
different Environments will be inserted into the same pool.  Once that
occurs, we may expect that a server spawned with config defined in
vhost A will be parcelled out to vhost B.


The Apache httpd 2.3 docs do not address the symlink issue at all, and
the virtual host issue only indirectly.
http://httpd.apache.org/mod_fcgid/mod/mod_fcgid.html


I'd appreciate it if someone could confirm or deny the above.  If I'm
right, can we add it to the docs?  None of it seems obvious to me.
Apologies in advance if this is the sort of thing that belongs on the
dev list.  I'm happy to throw together a doc patch.

Thanks in advance 


P.S. having a lot of trouble getting this message posted to the list.  Not sure what's up
with that.

--
Danny Sadinoff
danny@sadinoff.com
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