innobackupex --incremental is very slow

MySQL is Percona:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 1244039
Server version: 5.7.19-17-log Percona Server (GPL), Release 17, Revision e19a6b7b73f

Innobackupex:
innobackupex version 2.4.13 based on MySQL server 5.7.19 Linux (x86_64) (revision id: 3e7ca7c)

OS:
CentOS Linux release 7.3.1611 (Core)

Disk:
SSD

Location: Google Cloud

I tried with 40 also - same result.

It is a new setup - the backup solution.
The server is already running for about 1-1.5 year

Thank you