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From: tensmekl@infonode.ingr.com (Kermit Tensmeyer)
Newsgroups: comp.databases
Subject: Re: Any experience with raw-devices?
Keywords: Oracle V6,Unix,raw-device
Message-ID: <1991Feb15.145523.28024@infonode.ingr.com>
Date: 15 Feb 91 14:55:23 GMT
References: <771@fdmetd.uucp>
Organization: Intergraph Corp. Huntsville, AL
Lines: 35

In article <771@fdmetd.uucp> petter@fdmetd.uucp (Petter Henrik Hansen) writes:
>Using Oracle with raw.devices on Unix.
>
>
>My questions:        Has anyone had any bad experiences while using
>	             Oracle on raw-devices?

	I had massive (30+%) improvment using raw devices to access the
	same data on the same phyiscal machine. Part of the speed up comes
	in bypassing the UNIX cache. [If it's not in the Oracle cache, then
	it's not likly in the U**X cache.] The second advantage is that you
	can have ulimit protection while accessing a large Database (ie 
	osh is not needed to execute.)
>
>
>		     What about backup of the database while running on
>		     raw-device. Any smart solutions?
	
	The real problem with backup is that TableSpaces as a whole must
	be backed up to a consistent state. It doesn't make much difference
	to a backup utility that you will backup 475 megabytes of Raw Storage
	( scpio ) or 475 Megabytes of Unix Filespace. (mcpio, scpio, mbru etc.)
>
>		     
>Petter Henrik Hansen,  Fellesdata a.s, P.O. Box 248, 0212 OSLO 2, NORWAY
>Phone : +47 2 52 84 02                            Fax   : +47 2 52 85 10
>E-mail : ...!mcsun!nuug!fdmetd!petter   or       petter@fdmetd.uucp
><The opinions expressed, if any, do not represent Fellesdata a.s>


-- 
Kermit Tensmeyer                        | Intergraph Corporation
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