System Administration - eXist: A NoSQL Database and Application Development Platform - page 396

During normal operation, the reported number of cache hits should always exceed
the misses (fails) by an order of magnitude. Remember that the caches need to warm
up by filling before you will see the optimum cache hits! You can determine cache
capacity by comparing the reported cache size against the used size of the cache. If
the number of cache misses starts approaching the number of cache hits, it is a sure
sign that the cache size needs to be increased.
Backup and Restore
One of the most important aspects of managing any database system is to ensure that
you have a robust backup policy in place. Should your server fail from a hardware or
software issue, it is often essential that you can rebuild the server and restore a
backup of your data. eXist provides two different types of backup:
Data copy
This is simply a copy of all files from eXist's data folder (typically
$EXIST_HOME/webapp/WEB-INF/data ) to some other location. The data must
always be copied when the database is in a consistent state, and the files are not
being written to. You can do this either manually (including via a system schedu‐
ler such as cron on Unix systems or as a Windows scheduled task) when the
database is shut down, or automatically by using eXist's scheduler.
The eXist scheduled job org.exist.storage.DataBackup can be enabled in
$EXIST_HOME/conf.xml and will attempt to create a copy of the database every
time it is run; it will also ensure that the database is in a consistent state when it is
run by switching into protected mode .
Data export
This is an export of the database, which means that all XML documents are seri‐
alized from the binary database files back into individual XML files, and a copy is
made of all binary documents. A data export is a serialized copy of the database
collection hierarchy and may target either a destination folder or a ZIP file.
On some combinations of operating system and JRE, eXist
may have trouble creating data export backups to ZIP files that
are larger than 4 GB. In this scenario, it is recommended that
you export to a destination folder instead of a ZIP file.
While the data copy variety of backup is always performed server-side, the data
export backup may be performed either client-side or server-side.