Novell GroupWise 7
GroupWise Mobile Server 2.03
Over a day GMS users do not get updates on their mobile PDA
devices, updates are also not visible via end-user WebPIM
interface.
During the same time GroupWise end-users face a decrease of
performance doing normal work within their mailbox.
This situation can last rather longer time from several
minutes up to few hours.
A reason behind this usually a GMS user that tries to
synchronize larger data into his GMS mailbox / PDA device.
It is caused by few mails with larger attachments, for
instance +5MB in size, that are requested by a GMS to be
synchronized. A situation may vary based upon how much memory
resources are available on the server where the POA is
loaded.
A Windows based GMS version during this sync process keeps
creating many SOAP requests for the POA to get attachment data
transfered. Due to a size of requested data Windows server can run
out of available TCPIP connections. Moreover, default TCPIP Windows
setting keeps a connection locked also on GroupWise POA site for
longer time still even after a data was transfered. The POA then
consequently cannot handle normal GroupWise client C/S
connections.
You can change a Windows TCPIP protocol behavior via Windows
registry. More details about fine tuning Windows server can be
found, for instance at:
You can adjust following registry settings:
TcpTimedWaitDelay
TCPTimedWaitDelay adjusts the amount of time that
TCP waits before completely releasing a socket connection for
re-use. Since a GMS server opens many connections to a GroupWise
POA to get data included in larger attachments, the Windows server
runs out of available entries in the TCP connection table. Even
when a request for data has been finished, the Windows server keeps
this connection still locked. This prevents other GMS users to get
new data synchronized in their GMS mailboxes.
Key:
HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
Value: TCPTimedWaitDelay
Data type: REG_DWORD
Range: 0x0 - 0x12C (0 - 300 seconds)
Default: 0x78 (120 seconds)
Recommendation: 0x1E (30 seconds or less based
upon a testing results in your production environment)
MaxUserPort
MaxUserPort sets the number of actual ports that
are available for connections, we set the highest port value
available for use by TCP. This setting enables GMS to open more
connections toward a GroupWise server thus allowing more
simultaneous synchronizations.
Key:
HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
Value: MaxUserPort
Data type: REG_DWORD
Range: 0x1388 - 0xFFFE (5000 - 65534)
Default: 0x1388 (5000)
Recommendation: 0xFFFE
TcpWindowSize
By default TCP will try to automatically negotiate
the optimal window size depending on the maximum segment size. It
initially starts at 16 KB and can range to a maximum of 64 KB.
Key:
HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
Value: TCPWindowSize
Data type: REG_DWORD
Range: 0x0 to 0xFFFF
Default: 0x4470 (17520 bytes, the Ethernet MSS
(1470)) multiple closest to 16 K)
Recommendation: 0xFAF0 (64240)
Few performance tests showed much faster
data transfer when a GMS version for Linux was used on
SLES10 server. Those tests were based upon a scenario when a test
PO with a mailbox filled in by several larger mails was
synchronized one-by-one by two GMS servers running on Windows 2003
server and SLES10.
Due to better performance of a GMS running on
SLES10, there are also no performance decrease problems on a
GroupWise server.
This improved performance on Linux is due to a
newer technology implemented in a Linux GMS code. The
Linux version of GMS streams attachments via the HTTP
protocol instead of via the SOAP. According to Nokia information,
this newer technology will be also implemented in a next GMS
version for Windows.