Backup to S3 and tar consuming all RAM

I’ve been running into issues with a Virtualmin server where all RAM is consumed. When I login and execute:

ps axo pid,vsz,comm=|sort -n -k 2

I see :

1114 764624 tar

In trying to weed out the issue, it seems to be a hung process.

[root@xxx ~]# ps ax | grep tar
1101 ? S 0:00 sh -c (cd /home/sitename && /bin/tar cfX - /home/tmp/.webmin/196007_672_2_backup.pl --listed-incremental=/etc/webmin/virtual-server/incremental/13505931293307 . | gzip -c | cat >/home/tmp/.webmin/672-/sitename.com.tar.gz) 2>&1
1113 ? S 0:00 sh -c (cd /home/sitename && /bin/tar cfX - /home/tmp/.webmin/196007_672_2_backup.pl --listed-incremental=/etc/webmin/virtual-server/incremental/13505931293307 . | gzip -c | cat >/home/tmp/.webmin/672-/sitename.com.tar.gz) 2>&1
1114 ? D 0:47 /bin/tar cfX - /home/tmp/.webmin/196007_672_2_backup.pl --listed-incremental=/etc/webmin/virtual-server/incremental/13505931293307 .

Is there a specific port that may not open causing this? Anyone know what port that may be?

This issue eventually brings the server to its knees. I’m not really sure where to go with it.

Suggestions?

Anyone seen any help articles suggesting the ports that need to be open for the backup to work? I haven’t seen anything that explains the protocol used for this.