Parallel databases on linux HA?

[Cary B. O'Brien]

> > mount for Linux seems to have an sync option.  It says 'All IO to the 
> > file system should be don synchronously.
> 
> mounting -o sync or using O_SYNC stops writeback caching but not read caching
> (so you file became writethrough cached)
> 

Well, then the man page is wrong, pretty seriously wrong.  Anyone know how
hard it would be to fix this so reads were sync. ?  I.E. reads ignore
the buffer cache?

(Ok, take a few seconds to check it out)

2.0.34 kernel tree
$ cd fs
$ find . -name '*.c' -exec grep -l O_SYNC {} \;
./block_dev.c
./ext2/file.c
./ioctl.c

Three little files, how hard could it be?  (HAHAHA).

(I haven't been following the kernel mailing lists -- but it sounds like
this is a bit of a religous topic).

Another question -- how much of a performace hist is using -o sync?

-- cary