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https://github.com/kevinveenbirkenbach/linux-image-manager.git
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38 lines
1.3 KiB
Bash
38 lines
1.3 KiB
Bash
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#!/bin/bash
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# Wrong scripped but good as a base to optimize later. See http://blog.tdg5.com/tuning-dd-block-size/
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# Since we're dealing with dd, abort if any errors occur
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set -e
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TEST_FILE=${1:-dd_obs_testfile}
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[ -e "$TEST_FILE" ]; TEST_FILE_EXISTS=$?
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TEST_FILE_SIZE=134217728
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# Header
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PRINTF_FORMAT="%8s : %s\n"
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printf "$PRINTF_FORMAT" 'block size' 'transfer rate'
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# Block sizes of 512b 1K 2K 4K 8K 16K 32K 64K 128K 256K 512K 1M 2M 4M 8M 16M 32M 64M
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for BLOCK_SIZE in 512 1024 2048 4096 8192 16384 32768 65536 131072 262144 524288 1048576 2097152 4194304 8388608 16777216 33554432 67108864
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do
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# Calculate number of segments required to copy
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COUNT=$(($TEST_FILE_SIZE / $BLOCK_SIZE))
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if [ $COUNT -le 0 ]; then
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echo "Block size of $BLOCK_SIZE estimated to require $COUNT blocks, aborting further tests."
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break
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fi
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# Create a test file with the specified block size
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DD_RESULT=$(dd if=/dev/zero of=$TEST_FILE bs=$BLOCK_SIZE count=$COUNT 2>&1 1>/dev/null)
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echo $DD_RESULT
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# Extract the transfer rate from dd's STDERR output
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TRANSFER_RATE=$(echo $DD_RESULT | \grep --only-matching -E '[0-9.]+ ([MGk]?B|bytes)/s(ec)?')
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# Clean up the test file if we created one
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[ $TEST_FILE_EXISTS -ne 0 ] && rm $TEST_FILE
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# Output the result
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printf "$PRINTF_FORMAT" "$BLOCK_SIZE" "$TRANSFER_RATE"
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done
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