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From: Andrew Armstrong <andrew at qdebit dot com>
Subject: Linux and Devices
Date: Sep 20 2000 5:58PM

I have some questions for anybody that is running Sybase on Linux. Since there
is no raw file device support in Redat Linux, Sybase is forced to store it's
databases as files. I have set up a database to be the maximum file size of 2GB.
The machine that Sybase runs on is a 6-way Xeon.

I have configured the database to run as 4 processes and also to run as 2
processes in the past. I have noticed that there is not a great performance
boost from running multiple processes in the current setup.

What I would like to determine is whether or not the database stored as a file
is locked by the kernel every time the database needs to write to the database.
It makes sense to me that if the database is treated as a normal linux FS file,
then the kernel would put a write lock on the file whenever it needs to do an
update , insert or delete.

If my assumption about the locking is correct, it would also make sense that
running multiple sybase processes would not give much of a performance boost ,
if every time one of the processes needs to write to the database the entire
database file is locked.

If anybody out there has run into similar problems or knows how to bypass the
problem please let me know. 

Also, if anybody out there has found a way to support raw file devices in linux
please let me know where I can find documentation on this.

Andrew Armstrong                                
Chief E-Commerce Engineer