| Q: |
Which configuration parameters affect the performance of Matisse? |
| A: |
Database Cache Size: The Matisse server manages a page cache in memory that should be sized to at least half of the available system memory for a dedicated back-end server, to speed up the performance of a production system. The CACHESIZ configuration parameter can be expressed in kilobytes, megabytes, gigabytes, or datapages.
Caution: If the size of CACHESIZ is larger than the available system memory, the cache can be swapped to disk, degrading the overall system performance.
Database Datapage Size: The Matisse database stores all data in basic units called datapages. A datapage is the minimum amount of data that can be read from or written to disk by the Matisse server in any single I/O operation.
The parameter 'PAGESIZ' specifies the size of a Matisse datapage in kilobytes. The value of PAGESIZ has some influence on the amount of bytes read or written for each I/O operation. When setting PAGESIZ for a database, you must take into account the amount of data that will be routinely modified in the database. The value of PAGESIZ could be set to 4 or 8 Kbytes for databases managing basic textual information. For databases managing mainly large digital assets (image, audio, or video), PAGESIZ could be set to 16 or 32 Kbytes. |
| Q: |
Are NFS datafiles supported? |
| A: |
No, Matisse datafiles must be defined on local disks in order to ensure performance and reliability. The Matisse Online Parallel Backup utility allows Matisse to perform full or incremental backups on NFS files, local files, or tapes. |
| Q: |
If I add a datafile to an online database and then later I re-initialize it, the datafile is gone. |
| A: |
When you add, remove, or extend a datafile, the Matisse server automatically updates your database configuration file in the 'config' file directory. This problem may occur if the server process does not have sufficient permissions to update the configuration file. |
| Q: |
What are the benefits of using raw-devices datafiles? |
| A: |
The Matisse database datafiles can be defined either on files or on raw partitions. Since the raw partitions bypass the operating system file system layer, the database read and write operations are faster (up to tenfold, depending on the operating system and the file system) and more reliable. When it comes to deploying a production application, we recommend to use raw partitions to speed up the production system and protect it against potential file system errors after a crash restart. |
| Q: |
What are the benefits of spreading the database across several disks? |
| A: |
Speed – the Matisse database server is implemented on top of kernel threads, and scales linearly as new disks or new CPUs are added; the more disks (to a point), the faster your database server will run. |
| Q: |
I want to move a Matisse database to a different platform. How can I do this? |
| A: |
You can easily move a database across different
UNIX platforms. You may either copy the datafiles or restore a full
backup on the target platform. To move a database from an UNIX platform
to a Windows NT platform or vice-versa, you will have to use the XML
export/import facility. |
| Q: |
mt_dba displays a database as 'online' but can't connect – what's wrong? |
| A: |
This will happen if you start a database and then do a reboot (or when running the server on Windows NT, if you disconnect from NT). The server process shuts down but the Matisse port monitor doesn't know the server is offline.
Solution (on all platforms):
- Open a command window
- Enter the following command
- >mt_pmadm -r -S <basename>
- where <basename> is the name of the database
- Close the command window
- With mt_dba, choose database –> select
- the database is not declared offline
- Select the database –> start
- to restart the database
|
