I've searched the docs as best I can and this forum and could not find any guidance.
TEMP: A path-specified location to store DML-generated temporary data.
This could be JOIN spills, temp relations like materialized subquery, or working data from INSERT or COPY, and could be large. I consider it like swap space so I assume it could be equal to physical memory. As such, the best practice is to combine DATA and TEMP (or DEPOT and TEMP) locations on the same partition. However, if it's necessary to put TEMP on root or its own partition, try to allocate free space at least equal to physical memory.
as I understand drhaller's question, he is looking for guidance, if 20GB or 50GB or ... GB free disk space is needed in the /tmp directory, when you install Vertica 10.1x for the first time and/or maybe when doing an upgrade from Vertica 9.x or to Vertica 11.x.
Any free disk space requirements for /tmp you or somebody else from the Vertica community could provide?
Thanks in advance for your guidance.
The Vertica RPM/DEB itself contains 2.1GB of content, so you'd need space to unpack that file, update the install and package database, and clean up. This would suggest at least 4 GB free space is required to install or upgrade (double the expanded package size as a safety margin).
Official recommendation is at least 40% of the disk space should be free. It is used by certain query execution operations, such as hash joins and sorts, in the case when they have to spill to disk. Such operations might also be encountered during queries, recovery, refreshing projections etc