A cluster glissando is a short accented glissando.

The general production of a cluster glissando is the same as for a Glissando.

A cluster glissando, however, is executed faster and is more accented than a glissando. It is more similar to a fast arpeggio than to a glissando. It can consist of only a couple of notes or cover a large span of notes. The cluster glissando can be produced upwards or downwards or even simultaneously upwards and downwards (X-cluster glissando).

A cluster glissando sounds like a glissando played so fast that the single notes are not distinguishable. The sound is perceived as a cluster rather than a glissando.

A cluster glissando is notated with a group of notes, an arrow between two notes or a cluster. The notes are combined with an arpeggio sign and the abbreviation gliss. The arrow-head shows the direction of the cluster glissando. 

If notation without all the note heads is used (like in the two last examples), the pedal setting must be indicated by means of pedal diagrams or similar. 

The whole harp.