Commands Check Performance Disk Commands Reading speed cache/buffer: hdparm Check cache reading speed: hdparm Sequential write speed: dd Check iops when random read/write (block 4K): fio Usage hdparm Command: hdparm -tT /dev/sdb Output: /dev/sdb: Timing cached reads: 12706 MB in 2.00 seconds = 6357.09 MB/sec Timing buffered disk reads: 346 MB in 3.00 seconds = 115.31 MB/sec Explain -t: Perform device read timings -T: Perform cache read timings Usage dd Command dd if=/dev/sdb of=2GB.bin bs=2G count=1 oflag=dsync Output: 0+1 records in 0+1 records out 2147479552 bytes (2.1 GB, 2.0 GiB) copied, 63.3605 s, 33.9 MB/s Explain: of=2GB.bin: output file bs=2GB: block size count: number of block oflag=dsync: use synchronized I/O for data Usage fio Command fio --randrepeat=1 --ioengine=libaio --direct=1 --gtod_reduce=1 --name=test --filename=test --bs=4k --iodepth=64 --size=4G --readwrite=randrw --rwmixread=75
