Lxd export takes ~30 minutes for 4 gb. is this normal?

[sudo] password for USER:
0.16user 2.10system 27:21.89elapsed 0%CPU (0avgtext+0avgdata 22800maxresident)k
228inputs+7920827outputs (1major+6824minor)pagefaults 0swaps
-rw-r--r-- 1 root  root  3.8G Jan 31 09:05 CONTAINER.tar.gz

Possibly, depends on exactly how large the container was and how fast your CPU and disks are.
gzip isn’t multi-threaded so it’d have used one CPU core for a while, reading and compressing possibly over 10GB of data to compress it down to 3.8GB.

So this doesn’t feel abnormal but maybe there’s a reason why you think your system would have been able to do this much faster somehow.

@stgraber is correct it depends on file system, number of files and file size. I have development web page that holds huge amount of small files, container size 6G. Snapshot and export takes up to ~ 1h on Dell R710 server