Redis and its memory limit

Ferry tells Redis to use 3/4 of its memory limit for data.

Ferry sets maxmemory to 3/4 of the limit: 192 MiB for a limit of 256 MiB.

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maxmemory is a setting of Redis. With it, a full Redis refuses writes. Without it, the kernel stops Redis at the memory limit.

Redis uses the other quarter to save its append-only file and for the buffers of clients.

Change it

Change the memory limit of the datastore. Ferry sets maxmemory again.

Terminal

ferry db create cache --kind redis --memory 256M
ferry db update cache --memory 512M

Set the limits of a datastore

The limits of a datastore apply to its container immediately, with no restart.

Server defaults

A service or a datastore with no limit of its own gets the defaults of the server.