Innobackupex get maximum speed out of backup to remote server?

Hi I’m running a live backup and trying to configure innobackupex to get the maximum speed out of the backup. I’m using threads and compression but can’t seem to get any more speed out of the backup. The source server is a linux 20 CPU’s and 130 GB RAM and the receiving server is linux with 16 cpus and 60 GB RAM. Both servers are not reaching their maximum load during the backup. I have 2 Gbit/s network capacity but the backup is only using 500Mbit/s. I’ve adjusted compression and threads to tweak things but it doesn’t seem to change much. Below is my current configuration. Are there suggested compression and thread settings to get maximum throughput, or another method that I should be using for a live backup? Thanks.

innobackupex --defaults-file=/mnt/data/slave/my.cnf --host= --safe-slave-backup --no-lock --skip-secure-auth --user=backup --password=xxxxxx --stream=xbstream --compress --compress-threads=10 --parallel=30 /mnt/data/slave | ssh backup@ “cat - > /mnt/data/databases/slave/slave.xbstream”

I would try without compression, and I would use nc or ncat instead of ssh for the maximum speed.