What dcache is
A dcache is a storage method for data of temporary value. It's effective
in terms of size and space.
What dcache is not
A dcache is not meant to hold mission-critical data which cannot be
recovered. Data in a dcache may be deleted at any time, if need arises.
This is not a bug but a feature.
A dcache is potentially vulnerable to corruption problems if the process
writing to it is killed or crashes during some non-atomical operations.
The code has been written to minimize the window during which this can happen,
but still serious corruption of the index can occur.
In most of these cases dcachedump should be able to dump the content
of the cache.
Applications for dcache
- Imagine a man pager
storing the preformatted manual pages in a dcache.
- Likewise: browser cache.
- Likewise: web server cache.
- Log file storage. Log files are important, but often fill up
the hard disk - and some logs aren't that important ...
- Any kind of data (including shell script output) you don't want to
throw away _now_, but would like to keep for some time, but not
forever.