A. Microsoft released a hotfix ( support.microsoft.com/kb/938486) that mitigates the Exchange mailbox server massive paging issue. The paging storm—massive working-set trims across all processes that cause severe performance degradation—is triggered when a driver calls MIALLOCATECONTIGUOUSMEMORY during normal runtime (which should only be called at driver initialization). This causes the cache manager to trim nearly all the working sets from all processes if a contiguous range of memory can’t be found to fulfill the request. These operations tank server performance.

The HP iLO driver displayed this bad behavior in Microsoft dogfood, as did the Windows Server 2003 SP2 Broadcom NIC drivers with TCP Chimney offload enabled. The hotfix limits the number of trim operations per process to 8,192 pages and reduces the performance degradation.