Performance issues

[mobeacon]

I'm trying to use node-avro-io to serialize and persist HTTP request events into a few files.

rotatableFile = "events.avro"
var writer = avro.open(rotatableFile, schema, { flags: 'w', codec: 'null' });
writer.append(...)
writer.end()

With a code above performance of my app is ~60 req/sec.
When avro logging is disabled server handles ~700 req/sec.

In both cases test command is the same:

wrk -t5 -c500 -d5s -s"events_json.lua" localhost:3000/test

With snappy compression enabled performance falls further to ~25 req/sec.

My guess is that append operation is synchronous. Could you please advice on how can I improve performance?