11-2-4 硬碟測速

1. 簡單硬碟測速指令
   hdparm -t /dev/sd[a-h]
    
2. dd.sh (出處：pveCLI)
   測試使用 dd 指令時最佳 bs 值

   #!/bin/bash
   
   # Since we're dealing with dd, abort if any errors occur
   set -e
   
   TEST_FILE=${1:-dd_obs_testfile}
   TEST_FILE_EXISTS=0
   if [ -e "$TEST_FILE" ]; then TEST_FILE_EXISTS=1; fi
   TEST_FILE_SIZE=536870912
   
   if [ $EUID ]; then
     echo "NOTE: Kernel cache will not be cleared between tests without sudo. This will likely cause inaccurate results." 1>&2
   fi
   
   # Header
   PRINTF_FORMAT="%8s : %s\n"
   printf "$PRINTF_FORMAT" 'block size' 'transfer rate'
   
   # Block sizes of 512b 1K 2K 4K 8K 16K 32K 64K 128K 256K 512K 1M 2M 4M 8M 16M 32M 64M
   for BLOCK_SIZE in 512 1024 2048 4096 8192 16384 32768 65536 131072 262144 524288 1048576 2097152 4194304 8388608 16777216 33554432 67108864
   do
     # Calculate number of segments required to copy
     COUNT=$(($TEST_FILE_SIZE / $BLOCK_SIZE))
   
     if [ $COUNT -le 0 ]; then
       echo "Block size of $BLOCK_SIZE estimated to require $COUNT blocks, aborting further tests."
       break
     fi
   
     # Clear kernel cache to ensure more accurate test
     [ $EUID ] && [ -e /proc/sys/vm/drop_caches ] && echo 3 > /proc/sys/vm/drop_caches
   
     # Create a test file with the specified block size
     DD_RESULT=$(dd if=/dev/zero of=$TEST_FILE bs=$BLOCK_SIZE count=$COUNT conv=fsync 2>&1 1>/dev/null)
   
     # Extract the transfer rate from dd's STDERR output
     TRANSFER_RATE=$(echo $DD_RESULT | \grep --only-matching -E '[0-9.]+ ([MGk]?B|bytes)/s(ec)?')
   
     # Clean up the test file if we created one
     if [ $TEST_FILE_EXISTS -ne 0 ]; then rm $TEST_FILE; fi
   
     # Output the result
     printf "$PRINTF_FORMAT" "$BLOCK_SIZE" "$TRANSFER_RATE"
   done