Tag Archives: delay

Remote Desktop Sessions Pause Or Exhibit Unresponsiveness – Lag Whilst Typing And Session Will Not Accept Mouse Inputs

Remote Desktop Services can be extremely useful, allowing users to access a terminal server or their company desktop computer from another location.  One very common complaint with RDP sessions is screen refresh delays and a delay when typing or trying to click on items using the mouse cursor.  It will appear to most that the session has become unresponsive for a period of 5-20 seconds, after this delay the session will return to normal for a period of several minutes before once again becoming unresponsive.  You may find that this issue becomes more apparent as more users connect to the specific terminal server in question and if all these users utilise several applications (i.e. Outlook, Word and Excel) together.

Causes for poor user experience when connected via RDP are varied but one of the most common is resource exhaustion or contention.  This in turn causes a delay in processing that appears as a pause or unresponsiveness.

Check that your computer or terminal server has sufficient Memory to cope with the current load.

The next thing to verify by using performance monitor is that the PhysicalDisk\% Idle Time is consistently high, that’s correct this should be 90-100% when the server is not very busy.

It is worth running performance monitor using the PhysicalDisk\% Idle Time counter whilst you are seeing the slowdowns, this will help identify if your hard disk or controller are causing contention and in turn the pausing or unresponsiveness.

If you do find that the “%Idle Time” keeps going very low then it’s time to consider some of the options below to help resolve the issue

  • Install a second drive or mirror set, move the Windows Page File to this second disk/array to reduce the load on the drive/array holding your operating system
  • Install additional memory into the computer or server, this will reduce paging to disk and will generally improve overall system performance
  • Migrate to or upgrade your existing RAID controller to a unit that had a Battery Backed Cache (Fast) or Flash Backed Cache (Newer – Faster) to significantly improve performance and alleviate the system
  • Migrate to faster hard disk drives, 7200, 10,000 or 15,000 RPM drives are amongst the fastest.  The SATA interface is slower than the SAS interface but is cheaper.  Try to invest in the fastest drives that you can to future proof the system and avoid future performance issues if you have to scale for more users.
  • Ensure that you have at least 20-25% free disk space on all partitions/drives
  • Defragment all drives on a regular basis to optimise read and write operations
  • A cheap solution for improving disk performance may be to turn on the Hard Disk Cache using “Device Manager” or in the event that you are using a RAID controller without a battery backed Cache module you will need to open the RAID Array Management Software and then enable Disk Cache within the management software as this feature will not be available within “Device Manager” in this instance.  Please note that this does have some risks and should be used with caution, you may loose data in the event of a sudden/unexpected loss of power to the system.  Consider using this option with a UPS and redundant power supplies to reduce the risk of power loss to the system.  As always ensure you have a reliable backup that is carried out at regular intervals.

Example – HP RAID Array Configuration Utility:

Example – Windows Device Manager:

Windows Server 2008 R2 or Windows Small Business Server 2011 is slow to respond or may stop responding for 10-20 seconds

If your Server is running Windows Server 2008 R2 Service Pack 1 or Windows Small Business Server 2011 Service Pack 1, you utilise RAID and have more than 4GB of memory then you are likely to be affected by this issue.  It seems to impact those servers running memory hungry applications such as Microsoft Exchange, Microsoft SQL Server/Express and Microsoft SharePoint the most.  It can cause the server to operate slowly and/or stop responding for 10-20 seconds to requests.

This issue is related to a limitation in the memory allocation of the storport.sys driver, this file is part of the Microsoft operating system.

All is not lost as Microsoft do provide a solution/fix. The first step is to ensure that your current RAID Controller driver is upto date, the latest version can usually be found on the server manufacturers support site or if you are not sure which update/driver applies to your system then contact the manufacturers technical support by phone or e-mail.

Please note that for HP Smart Array controllers you should be using Driver version 6.28.0.64 (Released 18th Feb 2014) or later for this change to take effect (Enables customers to make use of Microsoft HotFix which enables 64-bit command addressing described by MS KB2468345).

Now that we have the latest RAID controller driver installed lets ensure that we have the latest version of storport.sys installed, the latest version for Windows Server 2008 R2 to date is available from Microsoft using the following link http://support.microsoft.com/kb/2528357 we need this newer version of Storport because the version included with Windows Server 2008 R2 and Windows Server 2008 R2 – Service Pack 1 does not correct the memory allocation limitation.  Once the storport.sys hotfix (KB 2528357) is installed on your server you can proceed to the final step of resolving the overall issue.

The final step is to create a registry entry under the RAID miniport driver to allow it to address more than 4GB Memory via the storport.sys driver that we have updated.

We need to add a registry key so lets open Registry Editor by either typing regedit in the Start Search box or the Run Command and then pressing “Enter”

You will need to browse and locate this registry key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\<MINIPORT>\Parameters

In place of <MINIPORT> in the example key above you need to enter the name of the Storport miniport driver that is in use on your particular server, i have attached a screenshot of where you can find this information, the example is based upon a HP Smart Array P410i Controller (HpCISSs2) but the principle is the same for most brands of server and RAID controller.

For the HP ProLiant server this Registry key would be: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\HpCISSs2\Parameters

Once in the correct key click on the “Edit” menu, click “New”, and then click “DWORD Value”

Type Supports64BitAddressing, and then press “Enter”.

Right-click Supports64BitAddressing, and then click “Modify”

In the “Value data” box, type a value of 1

Your entry should look like the screenshot below

Close the Registry Editor and Restart your Server.

Now the RAID miniport driver that uses the Storport.sys driver can access more than 4 GB of physical memory and it should resolve your performance issue.