NFS mounting on a NAS

I recently had very slow performance performing a simple rsync command to backup my laptop home directory to a home made NAS.

At first I assumed slow network, or slow disk storage.  But looking at the system monitoring showed under utilised network and the local write performance from "dd" was over 8MB/sec.

So something I should have remembered was the async flag in the NFS  filesystem /etc/exports file:


/media/2TBDiskRaid *(rw,no_root_squash,async)
/media/2TBDisk *(rw,no_root_squash,async)

Without this writing many small files is excruciatingly slow.  A quick edit of the file and exportfs -a - and the rsync starting to fly.  It feels like this should be a default, those needing synchronous behaviour are probably the minority nowadays...