We were trying to get performance out of our x4600's too. I found a x4600 manual on Sunsolve that explained things. "With just two or four DIMMs populated, the system runs memory at 667MHz. With 6 or 8 DIMMs populated, the system runs memory at 533 MHz." You must fill out the DIMMs from top to bottom. If you fill up only the white DIMM slots you will be running at maximum memory speed. Once you use the black DIMM slots your memory speed drops by 20%. So if you ordered the system with 16 GB RAM per CPU module, Sun will typically configure it as 2GBx8. We had to change our order to get 4GBx4. Bryan joe fletcher wrote: > It's memory management on the Opterons. If we rip out most of the DIMMs it > speeds up. The machine originally had 256Gb and was pushing data half the > speed of our other machines with 128Gb fitted. If we run the tests with 32Gb > it behaves fine. We're playing with the hardware config to find out where the > tiping point is. > > Cheers > > Joe > > ________________________________ > > > > Hi, > > This is a bit woolly so apologies in advance. > > Got some new x4600, 8x quad core Opteron boxes, 256Gb RAM attached to EMC > Clariion cx380s via Emulex LP10K HBAs. Kernel rev is 127112-11. We have a big > financial app that we're trying to migrate from a 6900 but when it comes to > filesystem performance it's dragging. > > We've done some testing with iozone and the Opterons seem to be consistently > slower than the SPARCs. For example on one of our write tests the AMDs do it > in approx 1 min whereas an old v490 can do the same test in under 20s. > > We discovered last night that if we use ZFS we can get the AMDs to behave > however we're not sure about ZFS support for the application. > > We've tried various tuning eg maxphys, sd-max-transfer, sd throttling and so > on. Things that seem to work on the SPARCs provide no apparent benefit on the > AMDs even though the docs indicate they should. > > Does anyone know of where we might look to get UFS to perform up to > expectation? > > Cheers > > Joe > _______________________________________________ > sunmanagers mailing list > sunmanagers@sunmanagers.org > http://www.sunmanagers.org/mailman/listinfo/sunmanagers > _______________________________________________ > sunmanagers mailing list > sunmanagers@sunmanagers.org > http://www.sunmanagers.org/mailman/listinfo/sunmanagers _______________________________________________ sunmanagers mailing list sunmanagers@sunmanagers.org http://www.sunmanagers.org/mailman/listinfo/sunmanagersReceived on Thu Oct 16 12:33:39 2008
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