I have a new Dell PowerEdge T320 server with 1 SSD non-RAID and 3 HDDs in RAID 5 all on one Perc H310 controller. RAM is 48 GB and I have Windows Server 2012 R2 Data Center installed on the SSD.

I initially was attempting to create a VHDX on the RAID. The VHDX to create was of fixed size (over a 100 GB) and attempts to do that through the GUI and PowerShell both failed with I/O errors and crashes.

I then, in an attempt to find the problem, tried a simple copy and paste of a 50GB VHDX from the SSD to the RAID. That also caused a crash. I tried further to copy a large file (120 GB) created using fsutil from the SSD to RAID, again fail.

I read somewhere that there was a problem with large files and caching when using the default copy command, so I got a suggested tool "terracopy" which has the option (default) to have system write cache disabled. That went on copying for some time before I decided to stop it since it seemed to be working.

My main need is to create a large VHDX, does anyone have a clue what is going on?

Edit: Additional details:

  • Ran Diagnostics, did not yeild anything useful.
  • Dell replaced the RAID controller, no change.
  • Installed Windows 8 to test the copy and paste, it went on copying for a relatively long time before I stopped it since it looked like there would be no crash.
  • Booted from Linux Puppy USB, did a copy paste of a 120GB file from the SSD to the RAID, no issues.
  • 1
    sounds like a hardware problem to me. It should be no problem copying file >100GB with normal OS copy commands. It seems the SSD is always involved, try to a copy operation without it. Feb 4 '15 at 8:01
  • @PeterHahndorf I tried coping from an external drive, still failed.
    – 3m3sd1
    Feb 4 '15 at 8:11
  • 1
    Yeah. Change from "I have a server" to "I have a broken server". Smells like some hardware is off. ECC ram? If not - run a memory test.
    – TomTom
    Feb 4 '15 at 9:29
  • is the drive encrypted i.e. with bitlocker ? if so the destination needs to be using the same bitlocker encryption.
    – JJJJNR
    Feb 4 '15 at 10:41
  • @JJJJNR No encryption whatsoever, fresh windows installation.
    – 3m3sd1
    Feb 4 '15 at 11:19

This looks like the old Server 2008 issue they eventually fixed with release of the Dynamic Cache Service addon: http://www.microsoft.com/en-us/download/details.aspx?id=9258

In a nutshell reads and writes are cached to memory which eventually fills it and makes the server unresponsive.

I couldn't find anything regarding server 2012 and this, but the behaviour looks the same. In the past I've seen Robocopy cause the same issue.

The XCOPY /J unbuffered copy bypasses this issue.


Dell replace the controller without anything to say that it was the issue? Weird. Tell them the problem still exists and to replace everything. Proc/board/ram until fixed.

  • Could it be a Windows problem? I successfully managed to copy the file using TeraCopy. Also, another version of Windows (Windows 8) did not seem to cause an issue.
    – 3m3sd1
    Feb 4 '15 at 23:53
  • Can't see it being a windows issue, I copy large files a lot and have never come across this issue, you could try running process mon at the time of the copy and see where the process fails.
    – JJJJNR
    Feb 5 '15 at 0:04

Had a similar issue with a Dell controller. When the RAID5 virtual disk on the controller is set to write-through, the copy performance issue exists. When the virtual disk is switched to write-back, the problem disappears.

You could also try using XCOPY with the /J parameter to use unbuffered IO. This will avoid the file system cache overhead and prevent the file system cache from being effectively flushed by the large file data.

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