Kbase 20738: SonicMQ and the 2 Gb Limit
| Autor |
Progress Software Corporation - Progress |
| Acesso |
Público |
| Publicação |
10/3/2002 |
|
SUMMARY:
This solution applies to SonicMQ 2000.x and 3.0.x and discusses the
2 Gb file size limit and how it may affect SonicMQ.
EXPLANATION:
The "2 Gb limit" has been mentioned most often as a limitation of the
Cloudscape database, the embedded database used as the persistent
store by SonicMQ by default. In fact, this limit is not unique to
Cloudscape or to SonicMQ. It is the result of the interaction of the
OS with certain JVMs, which limits the maximum address to which the
JVM can perform a seek in a random access file to 2 Gb (2147483648).
This effectively is a limit on random access file size.
The Cloudscape database stores each table and index in a separate
file. In a SonicMQ installation, these files reside in the directory
<SonicMQ install dir>\SonicMQDB\seg0. A limit on file size is
therefore a limit on table size.
Because the maximum size of the recovery logs resident in
<SonicMQ install dir>\log is configurable with the broker.ini property
MAX_LOG_FILE_SIZE, if this is set to a value > 2147483648, the
recovery log files will also hit this limit unless the broker is
frequently shutdown from an administrative client and restarted.
SOLUTION:
The 2 Gb random access file size limit is not present when using a Sun
JVM of version 1.2.2_06 or greater. Users may wish to use such a JVM
if their storage needs might exceed 2 Gb, but because SonicMQ versions
up to 3.0.x have been certified only with pre-1.2.2_06 JVMs, the 2 Gb
must be regarded as a limitation of SonicMQ 2000.x and 3.0.x. This is
not an issue for later versions of SonicMQ, because they have been
certified with JVMs which are not subject to the 2 Gb limit.
As long as this limit is in effect, users must be sure to set
MAX_LOG_FILE_SIZE < 2147483648 so that the recovery log files do not
grow to this limit.
References to Written Documentation:
SonicMQ 2000 and 3.0 Release Notes
SonicMQ Support Products and Platforms at
http://www.sonicsoftware/products/platforms.htm
Sonic Knowledge Base Solution 20464:
SonicMQ: How Big Should My Recovery Log Files Be?