DJK(John) Robinson
djkr at msn.com
Mon Jan 28 08:23:58 CST 2008
Well, I've trawled the web, and come up with the usual bunch of conflicting, unsubstantiated tosh. My favorite was along the lines of "running RAID 1 completely eliminates the need for backup". Yeah, right. Step away from my system, sir. The consensus, though, is that the first partition goes next to the edge, with the last one by the spindle. People differ in saying what difference this makes - a lot or hardly any: http://partition.radified.com/partitioning_2.htm http://www.xsibase.com/forum/index.php?board=15;action=display;threadid=3452 8 I found PassMark Performance Test (30-day free trial) at http://www.passmark.com/products/pt.htm; I've no idea how good it is generally I tried this on first and last partitions on a 500GB disc and got results suggesting 25%-45% better performance on the *first* partition, which supports the 'edge is first is better' theory. I'm not publishing the results, because they weren't on a scientific basis, but I *am* going to put my active stuff first, near the edge, and my dormant stuff last! John -----Original Message----- From: dba-tech-bounces at databaseadvisors.com [mailto:dba-tech-bounces at databaseadvisors.com] On Behalf Of DJK(John) Robinson Sent: 28 January 2008 09:34 To: 'Discussion of Hardware and Software issues' Subject: Re: [dba-Tech] Performance in disc partitions Thanks, John. That would suggest higher transfer rates nearer the edge, with some cylinders holding more than others. Has anyone got any good links to this sort of stuff? Oh, and of course I'm still interested in knowing whether the 'first' partition is nearer the edge or the spindle... John -----Original Message----- From: dba-tech-bounces at databaseadvisors.com [mailto:dba-tech-bounces at databaseadvisors.com] On Behalf Of jwcolby Sent: 28 January 2008 00:57 To: 'Discussion of Hardware and Software issues' Subject: Re: [dba-Tech] Performance in disc partitions IIRC, the disk controller speeds up the writes as the tracks move outwards towards the edge of the platter. IOW there is more surface area on the outer tracks so they just bump up the waveform to allow more data to be written in that larger surface area. When thought of from that perspective, the outer tracks hold more data / track and so may require less head movement. I have no idea whether the first volume is on the inner tracks or the outer tracks. John W. Colby Colby Consulting www.ColbyConsulting.com -----Original Message----- From: dba-tech-bounces at databaseadvisors.com [mailto:dba-tech-bounces at databaseadvisors.com] On Behalf Of DJK(John) Robinson Sent: Sunday, January 27, 2008 7:47 PM To: 'Discussion of Hardware and Software issues' Subject: [dba-Tech] Performance in disc partitions I am about to partition a new disc. One partition will be very active in terms of reads and writes, another almost dormant. Is there any advantage in performance terms in having the active partition as the 'first' one on the disc? Or the last one? It's a long time since I was involved in disc layout at a low level, and I'm wondering whether 'cylinders' these days are still all the same size, with the data near the edge of the platter just more spread out than that near the spindle - or not? TIA John _______________________________________________ dba-Tech mailing list dba-Tech at databaseadvisors.com http://databaseadvisors.com/mailman/listinfo/dba-tech Website: http://www.databaseadvisors.com _______________________________________________ dba-Tech mailing list dba-Tech at databaseadvisors.com http://databaseadvisors.com/mailman/listinfo/dba-tech Website: http://www.databaseadvisors.com _______________________________________________ dba-Tech mailing list dba-Tech at databaseadvisors.com http://databaseadvisors.com/mailman/listinfo/dba-tech Website: http://www.databaseadvisors.com