Re: DB logging (was: Problem with the numbers I reported yesterday)

Bruce Momjian wrote:
>
> > What exactly do you mean by "raw devices" that it is not offered by
> > Linux? If I take a partition of one of my hard drives and I don't
> > make a filesystem on it, I can perform reads and writes on the "raw
> > device" /dev/hd?? or /dev/sd?? I didn't think these writes were
> > buffered (if that's what you're referring to), but I could be wrong.
>
> Your /dev/hd* goes through the the buffer cache, the raw versions
> /dev/rhd* does not.

Actually on Linux, there is no raw/cooked drive interface as in
Solaris. In Solaris, the /dev/dsk/ devices are buffered by the OS,
while their counterparts in /dev/rdsk are not. Linux only has the one
interface to the partition, which is raw. Code which uses these raw
devices (the filesystem code) must supply its own buffering.

Anyway, I don't want to prolong this tangential topic. Linux should
provide raw devices, but does not (as Solaris does) provide buffered
or cooked access to disks.

Ocie Mitchell