While attempting to upgrade your vCSA 5.5 to 6.0 you are confronted with this error:

Migration Failed Failed to download vCenter Server Support Bundle Logs

Make sure that your reverse and forward DNS match (not sure why VMware continues to insist on flawless DNS – Tedious!)

The solution to his upgrade error is to:

1. Truncate your databases

Truncate your databases using this command:

/opt/vmware/vpostgres/current/bin/psql -U postgres -t -d VCDB -c “select ‘truncate table ‘ || table_name || ‘ cascade;’ from information_schema.tables where table_name like ‘vpx_hist_stat%’ and table_type = ‘BASE TABLE’ order by 1” | /opt/vmware/vpostgres/current/bin/psql -U postgres -d VCDB

2. Make sure to tick the box to export your performance data

Success: