9 Replies Latest reply on Jun 6, 2007 9:51 AM by IdeCable

    Very slow I/O Disk to Disk copy

    JammyB Novice



      we've been using VM Server since the early beta releases and on the whole it's been OK for general server activity. However we now have a client who is installing SQL onto a VM and we are experiencing very slow file copies.


      I don't want to detail the numberous hardware and software combinations we've used, but needless to say what I'm about to explain happens on all host hardware setups and using both Windows and Linux flavours.


      Windows (XP and 2003) and Linux (fedora core5/6 64bit)

      Intel (P4 and XEON) and AMD (2600+ and beyond)

      Single HDD, multi HDD

      Software and Hardware RAID mirroring



      Basically we have a number vmdk's on the server and when we try to copy any file that's say 4GB in size to the same vmdk (eg G:\file.iso[/b] to G:\file2.iso[/b]) the transfer starts quite well but then deteriorates to nearly 40 minutes!  In some cases the vm will blue screen, especially if the vmdk is not pre-allocated.


      Another side effect of this is the VM becomes very unresponsive even though the cpu is nominal, thus other serives like Exchange become unstable. Outlook disconnects/reconnects frequently during the copy.


      In a native Windows or Linux host environment the disk copy of the exact same file will take 4-8 mins depending on disk configuration.


      Is there anyway we can speed up this type of disk-disk copying as my client is looking to install SQL on a native install of 2003, something I certainly don't want.


      Any ideas will be much appreciated as we've been banging our heads against a brick wall with this one.





      PS Even ESX v3.0 seems to display a similar sort of poor disk-disk copy.