I am getting Windows delayed write errors as well as ntfs errors on some of
my virtual servers that run SQL or SQLExpress. Is this a known issue or am
I just lucky?

Thanks
Andy

Andy C wrote:
> I am getting Windows delayed write errors as well as ntfs errors on some of
> my virtual servers that run SQL or SQLExpress. Is this a known issue or am
> I just lucky?

Where are your VHDs located on local (dasd) storage or on file server
(UNC over CIFS)?

That error indicates a throughput problem either a spindle-bound IO or
network IO constraint.

If both of your databases are hammering the underlying disk and you have
enough of these VMs running in parallel you can run into this problem.

Try running less VMs or separating your VMs onto separate disks and
controllers to allievate the IO bottleneck.

Yah, well i have a very fast machine with Raid 5 and I was only runing one
virtual machine on one server and 2 on the other. I have the same exact
set up at another location running VMware and I have no issues. These
installations are basically exact copys except for one is using vmware and
the other is using Virtual Server. Any ideas?

-Andy
"Richard Cardona" <Search.Archives@example.com> wrote in message
news:eoxVwlIdIHA.3400@TK2MSFTNGP03.phx.gbl...
> Andy C wrote:
>> I am getting Windows delayed write errors as well as ntfs errors on some
>> of my virtual servers that run SQL or SQLExpress. Is this a known issue
>> or am I just lucky?
>
> Where are your VHDs located on local (dasd) storage or on file server (UNC
> over CIFS)?
>
> That error indicates a throughput problem either a spindle-bound IO or
> network IO constraint.
>
> If both of your databases are hammering the underlying disk and you have
> enough of these VMs running in parallel you can run into this problem.
>
> Try running less VMs or separating your VMs onto separate disks and
> controllers to allievate the IO bottleneck.

Andy C wrote:
> Yah, well i have a very fast machine with Raid 5 and I was only runing one
> virtual machine on one server and 2 on the other. I have the same exact
> set up at another location running VMware and I have no issues. These
> installations are basically exact copys except for one is using vmware and
> the other is using Virtual Server. Any ideas?

Are you using virtual IDE or SCSI for your virtual hard disks? The disk
IO performance (and IO stack) is more efficient with SCSI.

I would add a virtual SCSI adapter and a blank VHD on a LUN and let
Windows discover this virtual SCSI adapter via Plug-n-Play. Once the
SCSI driver is enabled in the image, it becomes bootable as a virtual
SCSI disk.

Move your VHDs from the virtual IDE channel to the virtual SCSI adapter
on SCSI0:0 and retry your tests.

all my (virtual)servers are built with SCSI drives.


"Richard Cardona" <Search.Archives@example.com> wrote in message
news:%237d92XPdIHA.4196@TK2MSFTNGP04.phx.gbl...
> Andy C wrote:
>> Yah, well i have a very fast machine with Raid 5 and I was only runing
>> one virtual machine on one server and 2 on the other. I have the same
>> exact set up at another location running VMware and I have no issues.
>> These installations are basically exact copys except for one is using
>> vmware and the other is using Virtual Server. Any ideas?
>
> Are you using virtual IDE or SCSI for your virtual hard disks? The disk
> IO performance (and IO stack) is more efficient with SCSI.
>
> I would add a virtual SCSI adapter and a blank VHD on a LUN and let
> Windows discover this virtual SCSI adapter via Plug-n-Play. Once the SCSI
> driver is enabled in the image, it becomes bootable as a virtual SCSI
> disk.
>
> Move your VHDs from the virtual IDE channel to the virtual SCSI adapter on
> SCSI0:0 and retry your tests.