By default, MSMQ creates 50-MB MQIS database. This database uses a 50 MB file for data (called the data device in SQL terminology) and an 8 MB file for logging database transactions (called the log device in SQL terminology). In general, the log device should be 15 percent of the size of the data device.
The default 50 MB MQIS allows for approximately 3800 users and 3800 computers (with four public queues each), or 2000 users and 2000 computers (with 10 public queues each). If computers in your enterprise will not be sending authenticated messages, the default MQIS supports approximately 4800 computers with four public queues each, or 2200 computers with 10 public queues each.
Use the following table to determine the appropriate values for your enterprise.
Table 6.6
| Formula item | Value to use |
| computers | Number of independent clients and servers in your MSMQ enterprise. (No need to count MSMQ dependent clients). |
| Computer object size | 2.4 K |
| Public queues per computer | The average number of public queues on each computer |
| authenticated users | Number of users that will send authenticated messages |
Notes The computer object size increases by 2 K for each user account that you assign more than 8 access rights to (instead of assigning access rights to a group).
Because private queues are stored locally (on each computer), they need not be considered when calculating the required MQIS size.
The MSMQ site object and other internal MSMQ tables also require some MQIS storage space, but their size is relatively insignificant.
If the 60 MB limit of the limited version of SQL Server 6.5 is not adequate for your enterprise, you must obtain a retail release of SQL Server 6.5.
Because the MQIS is replicated between all controller servers, you should use the same size data and log devices on all MSMQ controller server within your enterprise.
If you need to increase the data or log devices after you have installed MSMQ, you can do so using Microsoft SQL Enterprise Manager. For more information, see "Increasing the Size of the MQIS Database" in Chapter 3, Managing Your MSMQ Enterprise.