DS-Client Database (Automatic Expansion)
Creation Date: August 29, 2008
Revision Date: September 20, 2012
Product: DS‑Client (Windows)
Summary
The free Microsoft SQL Server Express databases have the following limitations:
Microsoft SQL Server 2005 Express (For DS‑Client database) | SQL Server 2005 Express has a 4GB limit for the databases. SQL Server 2005 Express will use a maximum of 1 CPU, and can use up to 1GB of RAM (even if the computer has more). |
Microsoft SQL Server 2008 Express (For DS‑Client database) | SQL Server 2008 Express has a 4GB limit for the databases. SQL Server 2008 Express will use a maximum of 1 CPU, and can use up to 1GB of RAM (even if the computer has more). |
Microsoft SQL Server 2008 R2 Express (For DS‑Client database) | SQL Server 2008 R2 Express has a 10GB limit for the databases. SQL Server 2008 R2 Express will use a maximum of 1 CPU, and can use up to 1GB of RAM (even if the computer has more). |
Microsoft SQL Server 2012 Express (For DS‑Client database) | SQL Server 2012 Express has a 10GB limit for the databases. SQL Server 2012 Express will use a maximum of 1 CPU, and can use up to 1GB of RAM (even if the computer has more). |
If you reach the GB size limit of either database type, you have two options:
• upgrade to the full Microsoft SQL Server (which requires you to purchase the license)
• enable the DS-Client database Automatic Expansion feature
There is no workaround for the CPU and RAM limitations. If you require more processing capability, install the full licensed Microsoft SQL Server.
Details
The DS-Client database Automatic Expansion feature is a workaround for the maximum database size limitation in the free Microsoft SQL Server Express databases. When an Administrative Process (Local, Daily, Weekly) detects the DS-Client database is nearing the maximum capacity, it will automatically create a new database and move some of the backup set tables to that new location.
Expansion can continue forever, i.e., this solution overrides the 4GB (or 10GB) limitation of Express. In practice, the performance will be affected as the database is expanded, considering the CPU and RAM limitations.
This feature works only for Windows standalone DS-Clients. It does not work with Windows Grid DS-Client.
To activate the DS-Client database Automatic Expansion feature
1. Click DS-User > Setup > Configuration > Parameters.
2. In the DS-Client Configuration Parameters screen, select Automatically Expand DS-Client Database.
3. Click OK or Apply.
To configure the parameters for the DS-Client database Automatic Expansion feature
1. Click DS-User > Setup > Configuration > Advanced.
2. In the DS-Client Configuration Advance screen, select the category Miscellaneous.
3. From the Parameter drop down list, you can define the following configurations:
DBHighWaterMark | This parameter (in percent) sets the level at which the Daily Admin or Weekly Admin will automatically expand the DS-Client database to create a new, sequentially named “expand<nnnn>” database. The percentage is calculated against the maximum allowed size for an individual database (4GB or 10GB). range 0 to 100, default is 70 (percent) |
DBLowWaterMark | If the current amount of space used in an “expand<nnnn>” database is less than this parameter (in percent), Daily Admin and Weekly Admin can move backup set tables into that database. range 0 to 100, default is 40 |
4. Click OK or Apply to save the changes.
NOTES
• HighWaterMark is the trigger that the Administrative Process uses to determine if backup set(s) need to be moved out of a database.
• LowWaterMark is used to balance the distribution of backup sets among the expanded databases. During an Administrative Process (Local / Daily / Weekly), if backup set(s) need to be moved and all databases are past the LowWaterMark, a new expanded database will be created.
• What gets moved:
• The largest backup set is moved first (unless it would fill the new database higher than the DBHighWaterMark). Then the next largest backup set is moved and so forth, until the database fill level falls under the DBHighWaterMark (e.g. less than 70% for default settings).
NOTE: If a single backup set’s tables are larger than the 4GB (or 10GB) limit, it cannot be moved. In this case you will have to migrate to the full, licensed Microsoft SQL Server version.
• Only an entire backup set can be moved (it must all reside within the same “expand<nnnn>” database).
• All tables for a single backup set from both the dsclient and dsdelta databases are moved.
• When compared with using a single DS-Client database on a full (purchased) Microsoft SQL Server, the performance will be slower.
• How a DS-Client with expanded-databases would appear from SQL DB Manager:
DSCXXXX00002_dsclient
DSCXXXX00002_dsdelta
DSCXXXX00002_dslanfiles
DSCXXXX00002_expand0001
DSCXXXX00002_expand0002
Example: This DS-Client (DS-Client #DSCXXXX00002) has two expanded databases. Expanded databases contain both dsclient and dsdelta tables.