Check the [GoDoc module documentation](https://godoc.org/github.com/ipfs/go-ds-flatfs) for an overview of this module's
functionality.
### DiskUsage and accuracy
### DiskUsage and Accuracy
This datastore implements the [`PersistentDatastore`](https://godoc.org/github.com/ipfs/go-datastore#PersistentDatastore) interface. It offers a `DiskUsage()` method which strives to find a balance between accuracy and performance. This implies:
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@@ -53,19 +53,33 @@ written when the datastore is closed.
This means that for certain datastores (huge ones, those with very slow disks or special content), the values reported by
`DiskUsage()` might be reduced accuracy and the first startup (without a `diskUsage.cache` file present), might be slow.
FIXME: Fix text, we now use a json file.
If you need increased accuracy or a fast start from the first time, you can manually create or update the
`diskUsage.cache` file.
If you need increased accuracy or a fast start from the first time, you can replace the `diskUsage.cache` file (while the
datastore is not open), with the right disk usage value in size. I.e., in the datastore root:
The file `diskUsage.cache` is a JSON file with two fields `diskUsage` and `accuracy`. For example the JSON file for a
small repo might be:
$ du -sb .
3919232394 .
$ echo -n "3919232394" > diskUsage.cache
```
{"diskUsage":6357,"accuracy":"initial-exact"}
```
`diskUsage` is the calculated disk usage and `accuracy` is a note on the accuracy of the initial calculation. If the
initial calculation was accurate the file will contain the value `initial-exact`. If some of the directories have too
many entries and the disk usage for that directory was estimated based on the first 2000 entries, the file will contain
`initial-approximate`. If the calculation took too long and timed out as indicated above, the file will contain
`initial-timed-out`.
If the initial calculation timed out the JSON file might be:
