Disabling half of cores in DL785g5 results in Win2008 64bit reboots during start

[Jan Soska]

Hello,

due some performance testing reasons we have to disable half of Opteron cores in bios of DL785g5 (latest bios, 8x4core Opterons). After disabling, windows 2008 64bit sp2 (regularly patched) refuses to start, rebooting in cycle. When we enable rest of cores to original state, server boots to windows normally. As this is production server, we have small maintenance windows for any test.

We did similar tests with another G5 system - BL465cG5 running RedHat4, no issues with starting. Similarly - BL465cG7 running win2008 R2 - no issues. Currently we do not server suitable for tests

Does somebody have any idea what could be wrong?

Thanks

Jan

[Jan Soska]

Some bad news...

Our test resulted with 3cores enabled only (bios setting is to enable all core - 4). Looks like bios bug. HP suport case raised.

Jan

[Jan Soska · Accepted solution]

Problem solved together with HP Support by reseting server to default with system DIP switch number 6.

Now it looks we can freely disable half fo cores and boot our system.

Jan