Hello Markus, I'm trying to put your comments into practice. Can you illustrate this further?
My own focus on the physical hardware ======================================= If I have a single 73GB 15000 RPM hard disk that I use for my DATA. However, let's say my application only requires 16GB of data for SAPDB / MaxDB. Now one option I would consider it to partition the drive to 20GB forcing the fastest part of the drive to be used by the operating system. The outer tracks of a hard drive are faster for transfer rate... Illustrated on the bottom graph labeled "83073L0 Transfer Rate": http://www.storagereview.com/articles/200304/200304068C073x0_2.html This also has the advantage of forcing the data to be in a small zone of the disk - meaning that the disk heads do not have to move back/forth across tracks as much as if the data were spread across the entire platters. I don't know if this is indeed a good strategy or not with SAPDB (I have used it, but never benchmarked it). Your mention of the DEVSPACE behaviors ======================================== Your comments suggests some things I have not considered with SAPDB / MaxDB. With a single drive for data, logs on a second drive. Questions: 1. Is there a difference to have 4 x 4GB devspaces, or a single 16GB devspace? 2. Would there somehow be a benefit to giving the devspace a lot of slack? If I only need 16GB but have 73GB available on the physical disk - would using a 16GB vs. 73GB devspace matter in regards to performance? Any other hints or knowledge to share? Thank you. Stephen Gutknecht -----Original Message----- From: "D�hr, Markus ICC-H" [mailto:[EMAIL PROTECTED] Sent: Thursday, November 27, 2003 9:03 AM To: 'Schwarz, Christian'; '[EMAIL PROTECTED]' Subject: RE: DEV-Space Size - Size Data Cache [snip] And since you have only one connection that reads data (so only one thread is used) it doesn't matter how many devspaces you have in that case. I CAN be important concerning I/O, a general recommendation is that DEVSPACES are as big as the harddisks are, so that you get a) no overlapping/competing I/O b) enough I/O to spread over the disks. SIEGENIA-AUBI KG Informationswesen i.A. Markus D�hr SAP-CC/BC, SAPDB-DBA Tel.: +49 6503 917-152 Fax: +49 6503 917-7152 E-Mail: [EMAIL PROTECTED] Internet: http://www.siegenia-aubi.com -- MaxDB Discussion Mailing List For list archives: http://lists.mysql.com/maxdb To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
