Hi,
How much of my file writing, and filesystem operations such as creating
a new file/directory, will land in OpenBSD's disk/write cache without
touching the disk before return of the respective operation to my
program, for softdep or async UFS media and I never fsync() ?
This is relevant to know for any usecase where there may be a big write
load to a magnet disk *and* there's lots of RAM and "sysctl
kern.bufcachepercent" is high.
If those ops will be done in a way that is synchronous with the magnet
disk, the actual fopen(), fwrite(), fread() (for re-read of the data
that's been written but still only is in the OS RAM CACHE) etc. might be
so slow that a program would need to implement its own write cache for
supporting even small spikes in write activity.
Sorry for the fuss but neither "man" nor googling taught me anything.
Thanks!!
Tinker
