@Aaron "Is there a sustained difference or did it settle back ? "
Sustained, clearly. During the day all nodes read at about 6MB/s while this one reads at 30-40 MB/s. At night while other reads 2MB/s the "broken" nodes reads at 8-10MB/s "Could this have been compaction or repair or upgrade tables working ? " Was my first thought but definitely no. this occurs continuously. "Do the read / write counts available in nodetool cfstats show anything different ? " The cfstats shows different counts (a lot less reads/writes for the "bad" node) but they didn't join the ring at the same time. I join you the cfstats just in case it could help somehow. Node 38: http://pastebin.com/ViS1MR8d (bad one) Node 32: http://pastebin.com/MrSTHH9F Node 154: http://pastebin.com/7p0Usvwd @Bryan "clients always connect to that server" I didn't join it in the screenshot from AWS console, but AWS report an (almost) equal network within the nodes (same for output and cpu). The cpu load is a lot higher in the broken node as shown by the OpsCenter, but that's due to the high iowait...)
