Re: Informix 7.1/RAID/Veritas Volume Manager

I'll add my two cents worth here. We're using DEC's LSM product, which is esentially Veritas Storage Manager and I'm quite happy with it. IN my testing so far it has basically no impact on our performance and it provides us much more flexibility for striping disks then our DEC controller does. BTW, I am using SYBASE not Informix or ORACLE. We have not tested the mirroring capabilities of LSM yet as far as performance goes. As for the write cache in a controller. We turned ours on just to see how it worked. Its a good way to get depressed seeing how much time it normally takes to do an I/O to a real disk as opposed to just stuffing it in a buffer and saying its done. It made a big difference in our performance, but our application is essentially write only so that is to be expected. Regards, Jay Walters Royal Hong Kong Jockey Club Bo Forsberg (bforsber@ws262.sw.seisy.abb.se) wrote: : In article <3vnc8a$abi@www.tkna.com>, Wally Beddoe <wally@tkna.com> wrote: : >A word of advice... : > : >We are using RAID 5 / Oracle V7.0.16 / Sparc Storage Array / Sparc Volume : >Manager 2.0 / Sparc 1000 : > : >We have MAJOR performance problems, I/O bottlenecks, and are still trying : >to determine the problem. We have applied so many patches that even our : >patches have been patched. SUN has been unresponsive and we are : >currently working with a consultant to figure this out. God help us! : > : >Anybody want to buy a Sparc Storage Array? We know we can't get anything : >for ORACLE! : > : >-- : >Wally Beddoe Telekurs (North America) Inc. : >wally@tkna.com Stamford, Connecticut : >Semper Fi! (203) 353-8100 : > : > : If you use RAID 5 under a relational database you will, on average, get : performance problems, because RAID 5 performs miserably on writes. : I am suprised that SUN hasn't told you this. Before we bought the RAID : system, we asked HP, and they told us all the grim details about RAID 3 and : 5, so we knew what we had to expect (we use RAID 5 under our Oracle database : anyway because we need the fault tolerance and possibility to hot-swap : disks). : To avoid the worst performance hits I have *very carefully* distributed the : database files among the three RAID-5 arrays using the logical volume : manager. Our server is no bolt of lightning, but it is adequate. : Using a RAID subsystem with a large battery-backed cache memory (or "RAID-7" : or other vendor-specific solutions) should improve the performance on : writes. HP's newer RAID systems have battery-backed cache, and our next buy : will probably be something like that. : Have you tried configuring the array to do striping, simple mirroring or : even individual disks (if that can be done with the SUN array?) instead of : RAID 5, and checked the performance? : -- : +- Bo Forsberg -- Systems Engineer, ------------------- bofo@seisy.abb.se -+ : ! Information Technology, Computer and Network Services ! : ! ABB Industrial Systems AB dept. SEISY/QDD ! : + I speak only for myself (and to myself) but you are welcome to eavesdrop +