From owner-oracle-l@CCVM.SUNYSB.EDU Tue Mar 14 10:48:35 1995 Received: from ccvm.sunysb.edu by alice.jcc.com; (5.65/1.1.8.2/01Aug94-0142PM) id AA05897; Tue, 14 Mar 1995 10:48:27 -0500 Message-Id: <9503141548.AA05897@alice.jcc.com> Received: from CCVM.SUNYSB.EDU by CCVM.sunysb.edu (IBM VM SMTP V2R2) with BSMTP id 7237; Tue, 14 Mar 95 10:31:59 EST Received: from CCVM.SUNYSB.EDU (NJE origin LISTSERV@SBCCVM) by CCVM.SUNYSB.EDU (LMail V1.2a/1.8a) with BSMTP id 5881; Tue, 14 Mar 1995 10:17:58 -0500 Date: Tue, 14 Mar 1995 10:18:09 +0500 Reply-To: "ORACLE database mailing list." Sender: "ORACLE database mailing list." From: "SAWMTIM.SME.ORG" Subject: Re: UNIX Raw Devices X-To: ORACLE-L@CCVM.SUNYSB.EDU To: Multiple recipients of list ORACLE-L --Boundary-12408-0-0 Raw devices allow you to use more of the "advertised" space on the device and are somewhat faster. However, I don't believe these differences are dramatic enough to warrant the bother of dealing with raw devices. It's harder to deal with the files that support the tablespaces because you can't get at them directly, like if you want to move it to another device using the 'mv' command. This my opinion based on experimentation with raw devices on Sun platforms. --Boundary-12408-0-0 X-Orcl-Content-Type: message/rfc822 Received: 13 Mar 1995 21:10:14 Sent: 13 Mar 1995 17:23:06 From:"Phil Vassar " To: Multiple,recipients,of,list,ORACLE-L,ORACLE-L@CCVM.sunysb.edu Subject: Re: UNIX Raw Devices Reply-to: "ORACLE database mailing list X-Orcl-Application: Return-Path: X-Orcl-Application: Sender: "ORACLE database mailing list." X-Orcl-Application: X-To: ORACLE-L@CCVM.sunysb.edu, 0006410539@MCIMAIL.COM X-Orcl-Application: content-length: 1081 Greetings, We have a client that insists on raw devices for a large DB we are helping them implement. Having always been File I/O oriented we are not sure of the benefits/drawbacks. Anyone have a strong feeling one way or the other? And why? Thanks, Powel Crosley Eclipse Technology, Inc. 6410539@mcimail.com pv> Usually raw devices give a performance boost over file systems. Oracle is better at managing the I/O than the O/S. For security reasons you don't have to worry about datafiles being deleted. Increased use of disk space comes to mind the O/S overhead is not included. On large file systems this overhead can be a significant amount of space. If performance and security are primary considerations over maintenance go with raw devices. Drawbacks include limited backup flexibility... dd being the utility of choice vs tar or cp. Maintenance of raw devices can be more difficult especially if the O/S offers some sort of virtual disk management utility. If the O/S offers virtual disk management then maintenance becomes much easier and flexible using data files. --Boundary-12408-0-0--