> 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?
Sure there's a difference. If you have only ONE devspace then there will only be one datawriter writing the data to the disk which is good in sense of competing I/O but not so good in sense of parallel distribution. If you have four devspaces you will have for writers that CAN write parallely but since it's only one disk they will probably interfer with each other. I have never done such setup and have no experience on that but I don't think that's it's really a BIG matter. > 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? > You will need some more space to temporarily store pages for sorting (temp pages) in the devspace so getting close to 100 % database filling will make the system slow. Since you still have one disk the pages will spread around the 72 GB devspace but I don't think that it will make a difference to use let's say a 25 GB devspace or 72 GB since you stay on one disk. > Any other hints or knowledge to share? Our tiny little play system has 9 GB and is arranged although under RAID-5 with 9 x 18,1 GB harddisks. It's waste of space (we don't need it currently) but the I/O can be much more done in parallel without interferring so the system is VERY speedy :-) 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]
