> Hallo,
>
> I have the following issue with a W2K-Server VM:
>
> - when writing a file from within a CAD-Application direct to a network
> drive of a W2K-Server VM, the performance is very bad (about 5 minutes per
> 40MB file)
> - during the whole write process, the vssrvc.exe process of the VS Host
> consumes about 50 - 60% of CPU and the performance monitor shows a large
> number of Drive I/Os
> - when writing the same file first to a local drive and then copying it to
> the network drive, the copy-process will take only a few seconds
>
> I guess, the CAD-Application uses a special write algorithm that causes
> the vssrvc process and the drive access algorithm to a big stress (e.g.
> open file, write a block, close file to force write to disk, open file
> again ... etc.)
>
> I've tried to activate the write cache of the "MS Virtual SCSI Disk
> Device", but this option is locked in the device manager.
>
> Will this option affect a better write performance under this
> circumstances?
>
>
> additional system info:
> Host:
> - W2K3 Server with VS 2005 R2 SP1
> - 2 * 146GB/15krpm SAS as RAID1 at LSI MegaRAID Controller with Write
> Caches activated
> Guest:
> - W2K SP4 Server, VHD is connect as a MS Virtual SCSI Disk Device
> - VM Additions 13.715 are installed
>
>
> Thanks, Frank
>
>
>

> Hallo,
>
> I have the following issue with a W2K-Server VM:
>
> - when writing a file from within a CAD-Application direct to a network
> drive of a W2K-Server VM, the performance is very bad (about 5 minutes per
> 40MB file)
> - during the whole write process, the vssrvc.exe process of the VS Host
> consumes about 50 - 60% of CPU and the performance monitor shows a large
> number of Drive I/Os
> - when writing the same file first to a local drive and then copying it to
> the network drive, the copy-process will take only a few seconds
>
> I guess, the CAD-Application uses a special write algorithm that causes
> the vssrvc process and the drive access algorithm to a big stress (e.g.
> open file, write a block, close file to force write to disk, open file
> again ... etc.)
>
> I've tried to activate the write cache of the "MS Virtual SCSI Disk
> Device", but this option is locked in the device manager.
>
> Will this option affect a better write performance under this
> circumstances?
>
>
> additional system info:
> Host:
> - W2K3 Server with VS 2005 R2 SP1
> - 2 * 146GB/15krpm SAS as RAID1 at LSI MegaRAID Controller with Write
> Caches activated
> Guest:
> - W2K SP4 Server, VHD is connect as a MS Virtual SCSI Disk Device
> - VM Additions 13.715 are installed
>
>
> Thanks, Frank
>
>
>

> Hallo Sylvain,
>
> I have tested the VM (W2K Server) on both types of host servers (scsi and
> ide harddisks) with same result.
>
> The SCSI shunt driver is already installed on the W2K Server VM.
>
> As you write in your blog, the VS2005 probably has a poor performance for
> writing small data blocks in a VM.
>
> The overhead seems to be very big, cause CPU works at 80 - 100% for the
> "vssrvc.exe" process on the VS2005-Host while writing the file from within
> the client application to the network share on the W2K Server VM.
>
> Are there any configuration hints for VS2005 or SCSI Shunt Driver for VMs
> to affect this behaviour?
>
> Frank
>
> "Sylvain Lafontaine" <sylvain aei ca (fill the blanks, no spam please)>
> schrieb im Newsbeitrag news:(email address - cut out)...
>> Also, in your case, installing and using the SCSI Shunt Drive instead of
>> the ordinary SCSI drive or the IDE drive could give you a boost, see the
>> README file and:
>>
>> http://blogs.msdn.com/virtual_pc_guy/archive/2005/04/26/412411.aspx
>>
>> --
>> Sylvain Lafontaine, ing.
>> MVP - Technologies Virtual-PC
>> E-mail: sylvain aei ca (fill the blanks, no spam please)
>>
>>
>> "Franklin" <(email address - cut out)> wrote in message
>> news:u8I$(email address - cut out)...
>>> Hallo,
>>>
>>> I have the following issue with a W2K-Server VM:
>>>
>>> - when writing a file from within a CAD-Application direct to a network
>>> drive of a W2K-Server VM, the performance is very bad (about 5 minutes
>>> per 40MB file)
>>> - during the whole write process, the vssrvc.exe process of the VS Host
>>> consumes about 50 - 60% of CPU and the performance monitor shows a large
>>> number of Drive I/Os
>>> - when writing the same file first to a local drive and then copying it
>>> to the network drive, the copy-process will take only a few seconds
>>>
>>> I guess, the CAD-Application uses a special write algorithm that causes
>>> the vssrvc process and the drive access algorithm to a big stress (e.g.
>>> open file, write a block, close file to force write to disk, open file
>>> again ... etc.)
>>>
>>> I've tried to activate the write cache of the "MS Virtual SCSI Disk
>>> Device", but this option is locked in the device manager.
>>>
>>> Will this option affect a better write performance under this
>>> circumstances?
>>>
>>>
>>> additional system info:
>>> Host:
>>> - W2K3 Server with VS 2005 R2 SP1
>>> - 2 * 146GB/15krpm SAS as RAID1 at LSI MegaRAID Controller with Write
>>> Caches activated
>>> Guest:
>>> - W2K SP4 Server, VHD is connect as a MS Virtual SCSI Disk Device
>>> - VM Additions 13.715 are installed
>>>
>>>
>>> Thanks, Frank
>>>
>>>
>>>
>>
>>
>
>

> Also, in your case, installing and using the SCSI Shunt Drive instead of
> the ordinary SCSI drive or the IDE drive could give you a boost, see the
> README file and:
>
> http://blogs.msdn.com/virtual_pc_guy/archive/2005/04/26/412411.aspx
>
> --
> Sylvain Lafontaine, ing.
> MVP - Technologies Virtual-PC
> E-mail: sylvain aei ca (fill the blanks, no spam please)
>
>
> "Franklin" <(email address - cut out)> wrote in message
> news:u8I$(email address - cut out)...
>> Hallo,
>>
>> I have the following issue with a W2K-Server VM:
>>
>> - when writing a file from within a CAD-Application direct to a network
>> drive of a W2K-Server VM, the performance is very bad (about 5 minutes
>> per 40MB file)
>> - during the whole write process, the vssrvc.exe process of the VS Host
>> consumes about 50 - 60% of CPU and the performance monitor shows a large
>> number of Drive I/Os
>> - when writing the same file first to a local drive and then copying it
>> to the network drive, the copy-process will take only a few seconds
>>
>> I guess, the CAD-Application uses a special write algorithm that causes
>> the vssrvc process and the drive access algorithm to a big stress (e.g.
>> open file, write a block, close file to force write to disk, open file
>> again ... etc.)
>>
>> I've tried to activate the write cache of the "MS Virtual SCSI Disk
>> Device", but this option is locked in the device manager.
>>
>> Will this option affect a better write performance under this
>> circumstances?
>>
>>
>> additional system info:
>> Host:
>> - W2K3 Server with VS 2005 R2 SP1
>> - 2 * 146GB/15krpm SAS as RAID1 at LSI MegaRAID Controller with Write
>> Caches activated
>> Guest:
>> - W2K SP4 Server, VHD is connect as a MS Virtual SCSI Disk Device
>> - VM Additions 13.715 are installed
>>
>>
>> Thanks, Frank
>>
>>
>>
>
>