Concurrent I/O
- Thread starter Helez
- Start date
Rob Fitzpatrick
ProgressTalk.com Sponsor
Are you referring to the -directio DB broker startup parameter? You may find these Knowledge Base articles helpful.
How Does -directio Improve Performance?
AIX Performance Issues: -directio and syncd
Note that these articles are a few years old, and OS and file system design and behaviour does change over time. The -directio parameter can in some cases help your performance meaningfully, and it can also in some cases hurt you just as much. It is highly dependent on your platform, and also on your Progress version; you didn't mention your OS or Progress version.
In any case, don't decide to use this parameter or not use it based solely on what you read. Do testing on your platform with your application and capture performance statistics, with and without -directio, before considering a change to your current configuration. In other words, if you can't prove that it's better for you, don't use it.
How Does -directio Improve Performance?
AIX Performance Issues: -directio and syncd
Note that these articles are a few years old, and OS and file system design and behaviour does change over time. The -directio parameter can in some cases help your performance meaningfully, and it can also in some cases hurt you just as much. It is highly dependent on your platform, and also on your Progress version; you didn't mention your OS or Progress version.
In any case, don't decide to use this parameter or not use it based solely on what you read. Do testing on your platform with your application and capture performance statistics, with and without -directio, before considering a change to your current configuration. In other words, if you can't prove that it's better for you, don't use it.
Thanks for your support.
I've found one article from Progress support on this issue after all. It says:
LINK
Thanks again,
Helez
I've found one article from Progress support on this issue after all. It says:
At the time of this writing, running OpenEdge on an AIX system configured for Concurrent I/O has not been certified.
Concurrent I/O (CIO) can be specified for a file either through the mount command (mount -o cio) or via the open() system call with O_CIO as the OFlag parameter.
Since this can be configured at the OS level, and since the OpenEdge code uses standard OS calls to open and write to files, the type of I/O is transparent to the code and should not cause any problems.
But, while we believe that running with CIO should not cause any problems, without running a standard certification process using CIO, we cannot be absolutely sure.
In testing that was done on an AIX system in house using the standard ATM test suite, running the tests on a CIO file system showed a 20% performance improvement over tests run on a non-CIO file system.
Concurrent I/O (CIO) can be specified for a file either through the mount command (mount -o cio) or via the open() system call with O_CIO as the OFlag parameter.
Since this can be configured at the OS level, and since the OpenEdge code uses standard OS calls to open and write to files, the type of I/O is transparent to the code and should not cause any problems.
But, while we believe that running with CIO should not cause any problems, without running a standard certification process using CIO, we cannot be absolutely sure.
In testing that was done on an AIX system in house using the standard ATM test suite, running the tests on a CIO file system showed a 20% performance improvement over tests run on a non-CIO file system.
LINK
Thanks again,
Helez
