ceph bluestore bcache 磁盘对齐对于性能影响

1. 磁盘划分:

# for sd in a b c d e f g h i j k l m n o ; do fdisk -l /dev/sd${sd} 2>/dev/null| grep "^ 1"; done
 1         2048   1953523711  931.5G  Microsoft basic Data
 1         2048   1953523711  931.5G  Microsoft basic Data
 1         2048   1953523711  931.5G  Microsoft basic Data
 1         2048   1953523711  931.5G  Microsoft basic Data
 1         2048   1953523711  931.5G  Microsoft basic Data
 1         2048   1953523711  931.5G  Microsoft basic Data
 1         2048   1953523711  931.5G  Microsoft basic Data
 1         2048   1953523711  931.5G  Microsoft basic Data
 1         2048   1953525134  931.5G  Linux filesyste
 1         2048   1953523711  931.5G  Microsoft basic Data
 1         2048   1953525134  931.5G  Linux filesyste
 1         2048   1953525134  931.5G  Linux filesyste
 1         2048   1953525134  931.5G  Linux filesyste

 1         2048   1953525134  931.5G  Linux filesyste

 1         2048   1953525134  931.5G  Linux filesyste

"

1         2048   1953523711  931.5G  Microsoft basic Data

" 这组数据是 4k 对齐的

"

1         2048   1953525134  931.5G  Linux filesyste

" 这组数据没有对齐。 测试结果:

IOPS	LAYTENCH(us)
15.1k	2112.19
15.6k	2046.71
13.7k	2339.70
13.6k	2345.66
15.5k	2059.83
15.8k	2022.38
13.8k	2315.19
15.4k	2073.78
2431	13159.35
14.8k	2155.26
2353	13.59ms
2463	12990.86
2484	12878.30
2483	12.88ms
2399	13.34ms

重新分割磁盘，使其 4k 对齐:

# for sd in a b c d e f g h i j k l m n o ; do fdisk -l /dev/sd${sd} 2>/dev/null| grep "^ 1"; done
 1         2048   1953523711  931.5G  Microsoft basic Data
 1         2048   1953523711  931.5G  Microsoft basic Data
 1         2048   1953523711  931.5G  Microsoft basic Data
 1         2048   1953523711  931.5G  Microsoft basic Data
 1         2048   1953523711  931.5G  Microsoft basic Data
 1         2048   1953523711  931.5G  Microsoft basic Data
 1         2048   1953523711  931.5G  Microsoft basic Data
 1         2048   1953523711  931.5G  Microsoft basic Data 

 1         2048   1953523711  931.5G  Linux filesyste

1 2048 1953523711 931.5G Microsoft basic Data

 1         2048   1953523711  931.5G  Linux filesyste

 1         2048   1953523711  931.5G  Linux filesyste

 1         2048   1953523711  931.5G  Linux filesyste

 1         2048   1953523711  931.5G  Linux filesyste

 1         2048   1953523711  931.5G  Linux filesyste

测试结果:

IOPS	LAYTENCH(us)
14.4k	2218.46
12.8k	2491.61
14.6k	2198.55
13.4k	2391.14
14.5k	2208.98
14.6k	2187.69
13.4k	2388.60
14.6k	2186.71
12.9k	2484.72
14.1k	2262.33
14.9k	2140.23
14.8k	2161.52
12.4k	2585.81
13.0k	2286.72
13.7k	2327.26

附录:

https://rainbow.chard.org/2013/01/30/how-to-align-partitions-for-best-performance-using-parted/