Here is a list of parameters I found over time to improve the speed of my GlusterFS instances.
gluster volume set <volname> config.global-threading on
gluster volume set <volname> cache-invalidation-timeout 600
gluster volume set <volname> features.cache-invalidation on
gluster volume set <volname> group nl-cache
gluster volume set <volname> network.compression on
gluster volume set <volname> nfs.disable on
gluster volume set <volname> nl-cache-positive-entry on
gluster volume set <volname> performance.cache-invalidation on
gluster volume set <volname> performance.cache-size 1GB
gluster volume set <volname> performance.client-io-threads off
gluster volume set <volname> performance.iot-pass-through on
gluster volume set <volname> performance.io-cache on
gluster volume set <volname> performance.io-thread-count 8
gluster volume set <volname> performance.parallel-readdir on
gluster volume set <volname> performance.qr-cache-timeout 600
gluster volume set <volname> performance.readdir-ahead on
gluster volume set <volname> performance.write-behind-window-size 128MB
gluster volume stop <volname> && gluster volume start <volname>
Pleas keep in mind, that you can have different settings for your set up. Also don’t forget that GlusterFS relies on your network speed to. While I have a really fast disk underneath Gluster, the network speed is limited to 1Gbit/s. Due to this limitation, Gluster will not get faster than my network.