Re: File Systems vs. Raw Devices

hth (hhong_at_nova.umd.edu) wrote:
: In article <1994May25.183843.15365_at_rossinc.com>,
: Joel Gary <joelga_at_rossinc.com> wrote:
: >In article <2rnj3g$npt_at_samba.oit.unc.edu> Harold.Bauer_at_launchpad.unc.edu (harold bauer) writes:
: >>
: >> Experiences using file systems and raw devices.
: >> What are the administrative and operational problems of the two?
: >
: >Inevitably, someone will create a unix filesystem over your raw system.

	Oooh... never had this happen to me (yet). Bad thought, tho.
	The biggest hassle is not being able to back up the database
	by shutting it down and tarring some files off to tape:-) Except
	for that, it's mostly good. Easy to keep non-root users from
	trashing anything if you don't mount the diskspace.



: >

: >>     What are the performance gains (is there really a 50% gain in using


: >>        raw devices over file systems)?

	Can't tell you on SunOS, but on the systems I've worked with
	we've seen much more than 50%.. (300% on HP-UX 8.0, about the
	same on SCO/Unisys SVR3). After about a year, we just started
	putting all Oracle databases on raw partitions by default.

	In my opinion, if a filesystem is going to have some OS type
	buffer cache, why have the OS and Oracle both caching? I can't
	take the caching away from Oracle, but I can take it away from
	Unix.



: >

: >-- 

: >Joel Garry       joelga_at_amber.rossix.com       Compuserve 70661,1534

	Rory Reynoldson
	Gallup Organization
	System & Database Admin
	rory_at_cronus.gallup.com