00001004011400.zettel

title: Configure file directory places
tags: #configuration #manual #zettelstore
syntax: zmk
role: manual

Under certain circumstances, it is preferable to further configure a file directory place.
This is done by appending query parameters after the base place URI ''dir:\//DIR''.

The following parameters are supported:

|= Parameter:|Description|Default value:|
|rescan|Time (in seconds) after which the directory should be scanned fully|600
|worker|Number of worker that can access the directory in parallel|17
|readonly|Allow only operations that do not change a zettel or create a new zettel|n/a

=== Rescan
On most platforms, Zettelstore automatically detects changes to zettel files that originates from other software[^This includes most Linux distributions, macOS, and Windows].
It is done on a ""best-effort"" basis.
Under certain circumstances it is possible that Zettelstore does not detect a change done by another software.

To cope with this unlikely, but still possible event, Zettelstore re-scans periodically the file diectory.
The time interval is configured by the ''rescan'' parameter, e.g.
```
place-1-uri: dir:///home/zettel?rescan=300
```
This makes Zettelstore to re-scan the directory ''/home/zettel/'' every 300 seconds, i.e. 5 minutes.

For a Zettelstore with many zettel, re-scanning the directory may take a while, especially if it is stored on a remote computer (e.g. via CIFS/SMB or NFS).
In this case, you should adjust the parameter value.

Please note that a directory re-scan invalidates all internal data of a Zettelstore.
It might trigger a re-build of the backlink database (and other internal databases).
Therefore a large value if preferred.

=== Worker
Internally, Zettelstore parallels concurrent requests for a zettel or its metadata.
The number of parallel activities is configured by the ''worker'' parameter.
Its default value 17 is a good compromise when you think about the high variability of possible Zettelstore environments.

A computer contains a limited number of internal processing units (CPU).
Its number ranges from 1 to (currently) 128, e.g. in bigger server environments.
Zettelstore typically runs on a system with 1 to 8 CPUs.
Access to zettel file is ultimately managed by the underlying operating system.
Depending on the hardware, only a limited number of parallel accesses are desireable.
Since Zettelstore is a single-user software, the value 17 is quite reasonable, even for higher use.

On smaller hardware[^In comparison to a normal desktop or laptop computer], such as the [[Raspberry Zero|https://www.raspberrypi.org/products/raspberry-pi-zero/]], a smaller value might be appropriate.
Every worker needs some amount of main memory (RAM) and some amount of processing power.
On bigger hardware, with some fast file services, a bigger value could result in higher performance, if needed.

=== Readonly
Sometimes you may want to provide zettel from a file directory place, but you want to disallow any changes.
If you provide the query parameter ''readonly'' (with or without a corresponding value), the place will disallow any changes.
```
place-1-uri: dir:///home/zettel?readonly
```
If you put the whole Zettelstore in [[read-only|00001004010000]] [[mode|00001004051000]], all configured file directory places will be in read-only mode too, even if not explicitly configured.