Hi Fernando,

I have some information regarding the O_DIRECT flag.

IDS V10 detects automatically that it runs on Linux Kernel 2.6 and if KAIO
is enabled then it turns on the O_DIRECT flag!

To enable KAIO:

The libaio.so library is required, regardless of the distribution
or kernel level. At the time of writing, IBM Informix Dynamic Server V10.0
requires a minimum of libaio 0.3.96-3.

Please also read the release notes for more information!
bye
Sandor

IBM Informix Development Munich
Information Management
Hollerithstraße 1
81829 Munich Germany




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03.03.2005 18:45 raw devices in linux (O_DIRECT)










Hi,

I just installed IDS 10 on linux and this is what I have found:

- It required glibc 2.3.3 and I was using and old redhat 8, so I upgraded
linux to Fedora Core 3. Dependency fixed

- Required libstdc++.so.5, FC3 includes libstdc++.6[.0.3] so make a
symbolic link (yes I should downgrade but like with curses4 works fine)

- I can't use raw devices with FC3! it's depretacted, the new way is
using the O_DIRECT flag when opening the chunks, of course in a
close-source program like IDS the only hope is to open a feature request.

+ RHEL 4 has this deprecated options enabled so I don't think IBM
will be interested in this solution.

+ The advantage of O_DIRECT is you dont need to make the association
with the /dev/raw devices and rawio will be always in effect, also KAIO is
enabled by default with rawdevices.

+ The workaround is make a new linux-util and kernel package with raw
enabled.

I'll make my custom kernel and try.
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