INF: SQL Small Business: Licensing, Connections, and LimitationsID: Q179856
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This article describes the differences between the version of Microsoft SQL
Server included with the Microsoft BackOffice Small Business Server and the
retail version of SQL Server.
The version of SQL Server included with Small Business Server is very
similar to Microsoft SQL Server 6.5, with Service Pack 3 applied. The main
area of change is the manner in which licensing and user connections are
managed (discussed below). Other changes include:
SQL DMO
Error 1818 (SQL Server) CREATE/ALTER DATABASE failed
because resulting cumulative database size would exceed your
licensed limit of 1051 megabytes.
Microsoft BackOffice Small Business Server is available in 5- and 25-user
license versions. Customers may purchase additional client add packs, but
may not exceed 25 licensed users. SQL Server Small Business Version can
accept as many users as are licensed for the Small Business Server suite.
SQL Server Small Business Version can only be run on the version of Windows
NT included with the Small Business Server. It will not install or run on
any other version of Windows NT.
You can upgrade the individual components of the Small Business Server
suite. You can also upgrade Small Business Server Windows NT to the full
retail version of Windows NT, and the Small Business SQL Server will
continue to work. Even if you upgrade, the SQL Server Small Business
Version limitations outlined in this article still apply. Conversely, you
may install full SQL Server on a Small Business version of Windows NT. In
this situation, SQL Server has none of the Small Business version
limitations, but Windows NT will be restricted to the Small Business Server
number of licensed client connections (maximum of 25). You can not install
SQL Server Small Business Version on full retail versions of Microsoft
Windows NT Server.
For the Small Business Server, SQL Server capacity is limited using the
Concurrent Work Limit (CWL). The capacity limit is set to allow good
performance for the intended market of 5 to 25 users. As requests come to
SQL Server, an active request count is maintained. When the CWL is reached,
any further requests queue up and wait for an active request to complete.
The CWL is set to 5 in the version of SQL Server that is included in Small
Business Server version 4.0.
SQL Server will accept as many connections as are configured in the user
connections parameter in sp_configure. (The default is 15, and may need to
be increased.) With a 25-license Small Business Server, all 25 users will
all be able to use SQL Server concurrently. All 25 will maintain their
connections and work within the application. SQL Server is not limited to
five users at a time by the CWL. However, SQL Server will only physically
process five requests at a time. So if six users are trying to query SQL
Server at the same time, the sixth one is blocked until one of the first
five is completed. After this happens, and a request is available, the
sixth user's query is processed. To the users, there is no noticeable
effect. They are still active within the application, and are connected to
SQL Server and working. In a worst case scenario, performance may be
impacted.
However, for the Small Business Server market size (5 to 25 users),
performance should not be an issue. SQL Server queries should be short and
concise. In a real-world application, the likelihood that more than five of
25 users (20 percent) will concurrently run resource intensive queries for
long periods of time is negligible, if the application is well-designed.
Performance degradation should be minimal even when the maximum number of
users are connected.
One implication of the CWL is that new connections to SQL Server may appear
to hang, or possibly timeout, during periods of heavy activity. The
sp_server_info stored procedure is executed for any new connection made to
SQL Server, before the connection is available for client use. If the
number of active requests has already reached the CWL at the time of the
connection (that is, five SQL Server requests are currently being
processed), these queries must wait for the next available request before
they are executed. At this point, the connection will appear to hang. If a
login timeout has been specified for the application, and the connection is
still waiting when this timeout value is reached, the connection will fail.
Setting the login timeout to 0 (zero) will allow the connection to wait
until it can be processed. This situation should be very rare for
applications in the 5- to 25-user range.
Additional query words: SAM SBS
Keywords : SSrvAdmin
Version : WinNT:6.5
Platform : winnt
Issue type : kbinfo
Last Reviewed: April 13, 1999