Re: raw vs. cooked files under linux

How does one use O_SYNC with and ext3 filesystem on Linux? I don't see it mentioned anywhere. Normally I use raw but SA and management would rather use cooked. They would also rather use Postgres but that another story. Thanks >You assert that cooked files are as fast today as RAW on SANs. Have YOU >tested it? Are you comparing RAW to COOKED with O_SYNC? Or are you >depending on the vendor stats? Not me, not with my reputation, user >satisfaction, and my job at stake. > > sending to informix-list

Peter J Diaz de Leon wrote: > How does one use O_SYNC with and ext3 filesystem on Linux? I don't see > it mentioned anywhere. Normally I use raw but SA and management > would rather use cooked. They would also rather use Postgres but that > another story. > Probably the same way one does for any filesystem, by adding the O_SUNC flag to the oflag argument to the open() system call. So: out_handle = open( "/myfs/mychunkfile", O_WRONLY | O_SYNC ); But isn't ext3 a journaled filesystem? One would first off, not want to use a journaled filesystem for IDS chunks for several reasons: 1- Performance, the overhead of writing the journal records 2- No gain for the pain. You can NEVER use the journal to reproduce the file because it's state would always be to the moment. If the disk crashes you'll have to restore from the IDS archives anyway. Art S. Kagel