iostat

• tps: list of transactions per second. this is another way of saying I/O requests sent to the device

• blk_read/s: number of blocks read from the device per second

• blk_wrtn/s: number of blocks written to the device per second

• blk_read: the total number of blocks read from the device per second

• blk_wrtn: the total number of blocks written to the device.

• when you have a system under heavy I/O load, the first step is to look at each of the partitions and identify which partition is getting the heavier I/O load.

• once you have figure out where the I/O load is, the next step is to identify whether the I/O load is mostly reads or writes.

• let’s say a backup job is causing the increase in I/O, since the backup job is mostly concerned with reading files from the file system and writing them over the network to the backup server, you could possibly rule that out if the bulk of the I/O is due to writes rather than reads.

• there is also the command iotop that shows you all of the running processes on the server sorted by their I/O statistics.