Greetings! When I have seen "input/output" error on my Lustre system it is usually indicative of a networking problem. I would do the usual things of checking the cable connections. I also look at the OST log files. My FC5 /var/log/messages file would have "IMP_INVALID" messages on the OSS computer with the bad networking connection. Sometimes the fix has been as easy as replacing the cable (in my specific case Infiniband cable). I have also increased my timeout values above 100, but that is really only just masking the issue. Using a higher timeout value will give more access time so that user jobs do not fail, but the tradeoff is that the jobs will take longer to run as they wait for the I/O connection to work properly. Just my $.02. megan