I have a Pi B+ running openelec 6.0 and I am using it as backend/frontend to record over-the-air TV programs. So far everything seems pretty good aside from some performance issues. I am interested in performing some read/write test to determine the best device used for recording TV programs. In some cases I am recording while watching a previously recorded program. Since I am reading and writing to the same device (for example) microSD card I am interested in looking at some tests that provide some insight about my system. Can I perform a read/write test simultaneously? Another question; I havent used dd for performance test. I read from another post it is possible to use the following command. I am not sure what does /dev/zero and /dev/null means. Can I perform this in the microSD card where openelec is installed without deleting it? The next question is can I run both commands simultaneously? What would I do open two SSH sessions?
dd if=/dev/zero of=~/test.tmp bs=500K count=1024
dd if=~/test.tmp of=/dev/null bs=500K count=1024