make printable

Known issues

System issues

scp from operational machines to qcweb very slow.

Symptoms: scp from operational machines (as used frequently within the dfos tools) apparently gets stuck for seconds/minutes, may even time out. Connections with the web browser to the content on qcweb also time out. Symptoms look like network/connection issue, but they aren't.

Background: When this happened in August/September 2013, qcweb had undergone a change in nfs architecture, causing very inefficient disk I/O. With the many tarballs delivered to qcweb and being unpacked there (in the course of moveProducts: logs, plots), there was in addition processing load on the machine. This caused loads as high as 10 or 20. Even with a hardware upgrade from one to four cores, and additional memory, this load was very high.

Solution: After a simple reboot of the system the hanging processes, and the disk I/O issue did not show up again. See here the monthly/yearly load on qcweb, demonstrating how the issue build up over the two months of August and September 2013, and disappeared thereafter.