I can tell you my understanding - right or wrong! Operating systems keep lots of I/O queues . . at least these: - a queue for each HBA. - a queue for each LUN.
By spreading your db across multiple luns and hba's, you can get more parallelism - assuming your application can make use of the parallelism. This is why TSM also should have it's database defined using multiple volumes. So you get multiple db vols across multiple lun's across multiple HBA's. Will it help? It all depeneds . . . The best thing I have ever read about this topic is the following. It doesn't specifically address your question, but it goes into a deep dive about queuing. http://virtualgeek.typepad.com/virtual_geek/2009/06/vmware-io-queues-micro-bursting-and-multipathing.html Rick Henrik Vahlstedt <[email protected] > To Sent by: "ADSM: [email protected] Dist Stor cc Manager" <[email protected] Subject .EDU> disk question 04/21/2010 11:11 AM Please respond to "ADSM: Dist Stor Manager" <[email protected] .EDU> Hi, Are there any performance benefits in creating two or more LUN´s in the same RAID group for one RHEL 5, TSM 5.5 database, instead of only creating one LUN. If yes, why? Example: IBM Midrange System Storage Implementation and Best Practices Guide sg246363, see chapter 7.4/TSM database. //Henrik ------------------------------------------------------------------- The information contained in this message may be CONFIDENTIAL and is intended for the addressee only. Any unauthorised use, dissemination of the information or copying of this message is prohibited. If you are not the addressee, please notify the sender immediately by return e-mail and delete this message. Thank you
