Slowdown when copying huge (120+GB) files
I have a C# application and am using the FileStream class to read a 120GB file from disk. I start by getting 45 megabytes / second read speeds, but at about the 20GB range my read speeds drop dramatically and settle to about 9 megabytes / second. I have checked the disk and there is minimal fragmentation (I have 800 GB free disk space out of 1TB total with 2 1TB hard drives in RAID1). Does anyone have any ideas on what might be causing the slowdown?

Server is Windows Server 2008 Enterprise R2 64 bit and my app is a 64 bit .NET framework 4.0 console application. Here's my code:

            byte[] buffer = new byte[16777216];
            int count;
            FileStream file = File.OpenRead("bigfile.dat");
            while ((count = file.Read(buffer, 0, buffer.Length)) > 0)
            {
                // I track megabyte / second here
            }
Slowdown when copying huge (120+GB) files
===

I have a C# application and am using the FileStream class to read a 120GB file from disk. I start by getting 45 megabytes / second read speeds, but at about the 20GB range my read speeds drop dramatically and settle to about 9 megabytes / second. I have checked the disk and there is minimal fragmentation (I have 800 GB free disk space out of 1TB total with 2 1TB hard drives in RAID1). Does anyone have any ideas on what might be causing the slowdown?

Server is Windows Server 2008 Enterprise R2 64 bit and my app is a 64 bit .NET framework 4.0 console application. Here's my code:

            byte[] buffer = new byte[16777216];
            int count;
            FileStream file = File.OpenRead("bigfile.dat");
            while ((count = file.Read(buffer, 0, buffer.Length)) > 0)
            {
                // I track megabyte / second here
            }