Since more than a week I was working on fess to handle 100MB PDF files. Now it works. The following settings need to be done to run Fess stable w/o JavaOutOfMemory errors or crashes on a low end Intel Celeron J1900 with 8GB RAM under Ubuntu.
Step: You need RAM. 8GB is not enough. Additional 4GB RAM or virtual Memory is minimum, better more!
Set Threads under File Crawler Configuration to 3 and to 3 parallel Crawlers under General Configuration.
Deactivate all logging features
Deactivate Thumbnail creation
Configure Crawler schedules not to run more than 2 Crawlers in parallel. I have three Crawlers for different folders and they run on different times.
Under Crawler configuration parameter insert: max_size=104857600
In fess/app/WEB-INF/classes/crawler/contentlength.xml change
to 104857600 and “text/html” 20971520.
In /fess/app/WEB-INF/classes/fess_config.properties change to -Xms512m\n\ and -Xmx2g\n\
In /fess/bin/fess.in.sh change to
if [ “x$FESS_MIN_MEM” = “x” ]; then FESS_MIN_MEM=512m and if [ “x$FESS_MAX_MEM” = “x” ]; then FESS_MAX_MEM=3g in line 13 and 16.
I also closed all applications like Firefox to save RAM and run the following script in sudo crontab -e to reduce CPU load after reboot:
renice 19 $(pidof java)
Start in sudo crontab -e
@reboot sleep 120 && bash /home/xyz/bin/javalowcpuprio.sh