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Allocating Disk Space
A running BEA Tuxedo application needs disk space for system files and for the application's database(s). You do not use this space until you begin to develop or run your BEA Tuxedo application, but it is important to plan for this space before installing the software. The sections that follow describe how the BEA Tuxedo system handles files.
Note: Additional information on the commands described in these sections can be found in the following documents:
BEA Tuxedo System Disk Management Interface
The BEA Tuxedo system provides a facility that manages logical files within a single disk device or set of devices. This facility is called the Disk Management Interface (DMI). The DMI performs tasks such as storing binary configuration tables and the transaction log. You can use it to create, initialize, or destroy entries in the BEA Tuxedo file system. To access the DMI, use the tmadmin(1) administrative commands.
The BEA Tuxedo system disk management software supports the notion of a BEA Tuxedo file system distinct from any operating system file system. (For the rest of this discussion, the term "OS file system" is used to refer to any operating system file system.)
There are two ways the logical files managed by the DMI can be stored physically.
Files reside on device special files in the designated space and are managed directly by the DMI. Space outside the OS file system is usually referred to as raw disk space. Not only is I/O faster when it is done by system calls reading directly from and writing directly to device special files on raw disks, raw disk space is preferred when it is important to know for certain that a physical write() has been done. When using an OS file system, you cannot predict or control the precise moment at which a write() is done. The BEA Tuxedo system, however, gives you accurate control of the write operation. Such control is particularly important for entries in the transaction log. Also, when multiple users are accessing the system, being able to control the write operation is important for assuring database consistency.
Arranging for Raw Disk Space
If you decide to use raw disk space for your BEA Tuxedo application, and you are using a UNIX system platform, you may find that the hard disk devices on your system are fully allocated to file systems such as / (root) and /usr. If that is the case, you must repartition your hard disk device in order to set aside some partitions for use as non-OS file systems. For repartitioning instructions, refer to the system administration documentation for your platform.
Note: On NT platforms, I/O is unbuffered by default; no special arrangements are needed.
How the BEA Tuxedo File System Is Organized
A BEA Tuxedo file system has a Volume Table of Contents (VTOC) that lists the files that reside on a set of devices named in the Universal Device List (UDL). The UDL contains information about the location of the physical storage space for BEA Tuxedo system tables.
In a BEA Tuxedo application, all system files might be stored together on the same raw disk slice or OS file system file. While it is possible to use regular OS file system files for the configuration tables, we strongly recommend that you store the transaction log, TLOG, on a raw disk device. Because the TLOG seldom needs to be larger than 100 blocks and because disk partitions are always substantially larger than that, it may make sense to use the same device for both the configuration files and the TLOG. The path name of the device needs to be specified by both the TUXCONFIG and the FSCONFIG environment variables. The following sample listing shows a sample VTOC and UDL diagram for a bankapp configuration on a single machine.
VTOC and UDL Diagram
Output based on setting FSCONFIG=$TUXCONFIG, and invoking tmadmin:
No bulletin board exists. Entering boot mode.
> livtoc
Volume Table of Contents on /usr2/bank/tuxconfig:
0: VTOC: Device 0 Offset 0 Pages 7
1: UDL: Device 0 Offset 7 Pages 28
2: _RESOURCE_SECT: Device 0 Offset 35 Pages 6
3: _MACHINES_SECT: Device 0 Offset 41 Pages 40
4: _GROUPS_SECT: Device 0 Offset 141 Pages 100
5: _SERVERS_SECT: Device 0 Offset 241 Pages 150
6: _SERVICES_SECT: Device 0 Offset 391 Pages 60
7: _ROUTING_SECT: Device 0 Offset 451 Pages 100
8: _NETWORK_SECT: Device 0 Offset 551 Pages 20
9: _MIBPERMS_SECT: Device 0 Offset 571 Pages 2
10: _NETGROUPS_SECT: Device 0 Offset 573 Pages 2
11: _INTERFACES_SECT: Device 0 Offset 575 Pages 10
# If the TLOG is stored on the same device, there will be an
# entry something like:
12: TLOG: Device 0 Offset 585 Pages 100
The BEA Tuxedo application administrator must make sure raw disk slices are available as needed on each node participating in an application. The following table lists the size of each element in the BEA Tuxedo file system.
|
Entity |
512-byte Pages |
|---|---|
|
VTOC |
7 |
|
TUXCONFIG |
550 |
|
TLOG |
100 (default) |
|
UDL |
28 |
|
TOTAL |
685 |
The amount of space required for the TUXCONFIG file must be larger if there are more entries in the configuration file, UBBCONFIG, than in the bankapp sample application. The administrator is encouraged to allocate additional space for dynamic reconfiguration and growth of the application. The default block size assumed by the crdl subcommand of tmadmin is 1000 blocks, which should be adequate for the initial installation.
Space for Queue Spaces (If You Are Using /Q)
If your BEA Tuxedo application uses /Q for store-and-forward queue management, your queue space can be listed in the same UDL as the one used to store theTUXCONFIG file and the TLOG, and managed by the BEA Tuxedo System VTOC.
Space for Application Servers
As you are calculating your space requirements for the BEA Tuxedo system, you should also consider the requirements of the servers that perform the work of the application. These requirements are specified by the application; they are unrelated to the requirements for the BEA Tuxedo system itself (unless otherwise specified).
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Copyright © 2000 BEA Systems, Inc. All rights reserved.
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