VxFS performance measure

[Venkatesh marisamy]

I am reading 3GB file using Direct I/O and buffered I/O. I expected direct I/O performance to be better, but I got equal performance in both the cases. I read the files with block size 1MB for each read. My file system block size is 8kb. I verified un-buffered I/O in case of Direct I/O using a tool.
Using vxtunefs changed max_buf_data_size = 65536.

Please tell me any think else I should do to improve Ditect I/O performance.

[smatador]

Hi,
There is some doc about io performance, maybe the better is
http://docs.hp.com/en/7779/commonMisconfig.pdf
but you could also improve some way the performance in mounting the fs.
There is a good wp about mounting jfs/ direct IO and oracle normaly is here...but impossible to take it
http://h71019.www7.hp.com/ERC/downloads/4AA1-9839ENW.pdf
So my old one is in attach

Hope it helps