Decrease in overall system performance when you are copying files that are larger than approximately 500 MB in Windows Server 2003

[chuckk281]

A BladeSystem customer was running a performance test using a c7000 chassis with one BL490c G6 and four BL460c G6 all blades are running on Windows 2003 R2 x64 PSP 8.25. The customer viewed the I/O throughput from Windows Task manager on the four targeted BL460c hosts and noticed that 80% of the file transfer is performing at about 25% I/O Ethernet traffic throughput then I/O performance drops to 6% for the final 20% of the file transfer, on all four of the targeted hosts. The question arose as to why the performance drop in the final 20% of the file transfer. Well Joe found an issue with large file transfers in Windows 2003 x64. You may experience a decrease in overall system performance when you are copying files that are larger than approximately 500 MB in Windows Server 2003 SP1 or in Windows Server 2003 SP2 (see MS KB article below): http://support.microsoft.com/default.aspx?scid=kb;EN-US;920739 These settings are typically modified for high latency networks, but given the sheer speed of the 10Gb FlexNIC, it appears that they do come in to play here as well.