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Windows Server 2008 R2 Transfer Speed


I have just upgraded one of our data servers to Windows Server 2008 R2.
I also upgraded the hard drives.
So in summary....it is an Intel SR1500AL Server, with 3 X 1TB hard drives and setup as a RAID 0
I have just installed Windows Server 2008 Enterprise R2 64bit.

The problem is that when I try copy files between the partitions...between C:\ and D:\....or even if I try copy files on the same partition, D:\ to D:\....or from a external drive to the server. The transfer speed is unbelievably slow! I am getting transfer speeds of 1-2MB\s!!!
And I should be getting 80-120MB\s????
(see attached image)

What would be causing this to be so slow? And how can I fix it?
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Top Expert 2010
Several things
 - Enable WRITE CACHE on RAID controller (assuming you have a UPS), but since you are doing RAID0, then you probably backup frequently anyway
 - Use something like robocopy (it is available on microsoft site if you search there). Robocopy uses larger block I/O and will copy much faster than the COPY command or explorer

You won't get 80-120MB for a lot of reasons.  Your PC architecture is such that all the disks can't perform I/O at the same time.  That is why people buy PCIe-based RAID controllers which let all disks do I/O concurrently.

Also source and target are on the same physical drives, so no matter what, half of the I/O is read, half write, so if you should get 80-120MB you will get 40-60MB copying from the same disk to the same disk.
Ditto the write cache comment.  Possibly you test this shortly after configuring the raid set so it is still initializing?  Check your raid management software for the volume status.  You might also look at the manage-server diagnostics to see total disk activity in case something else is using the drives and interfering with your copy.
Top Expert 2010
Just looked at the graphics.  you are also not considering all of the additional overhead.  the 80-120MB/sec is raw number for sequential access.  When you copy a lot of small files, you have to do a great deal of housekeeping on the disk drive.  You are building directory structures;  modifying last-access/write/read file descriptors; expanding files; doing NTFS journaling; finding free space to copy the next file;  reading source files; finding the next piece of files by looking at source directory structures  (is your source disk 100% contiguous).

You are also booted to an operating system, so are doing network traffic, have a few dozen programs resident doing I/O, operating system is creating windows events and dealing with dozens of additional log files.  You probably have 50 windows services running.  Active directory, ....

All of that stuff is using most likely 4KB I/O. So most likely you are getting every bit that you should expect from your architecture.  If you want better performance, then invest in a small industrial class SSD, and move C to that, and combine current C+D into a single device, and bump up NTFS allocation size and align it.
Overall performance should conservatively increase by factor of 25X.


Wasn't exactly what I was looking for, but information and suggestions where good.