Is GFS2 suitable for concurrent writes?

I need to setup a shared filesystem between two servers. These servers will need to write and read data on different files, but at the same filesystem.

I started installing an environment with three servers: the first one is sharing a block device via iSCSI and the other two are part of the same cluster and are accessing that device formatted as GFS2 mounted at /mnt.

When I ran on each server

dd if=/dev/urandom of=/mnt/block${hostname}

I saw the data rate was incredibly low: like 50kB/s. I've read the documentation at https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/6/html/global_file_system_2/s1-ov-lockbounce , which specifies the following:

Due to the way in which GFS2's caching is implemented the best performance is obtained when either of the following takes place:
- An inode is used in a read only fashion across all nodes.
- An inode is written or modified from a single node only.

Is there any way to get performance on concurrent writes to different files?