Linux文件系统格式Ext4，Ext3的特点和区别(2)

上述命令的说明如下：

Auto Mode
File size set to 4194304 KB
Using Maximum Record Size 256 KB
Using Minimum Record Size 4 KB
Command line used: /opt/iozone/bin/iozone -a -s 4G -q 256 -y 4
Output is in Kbytes/sec
Time Resolution = 0.000001 seconds.
Processor cache size set to 1024 Kbytes.
Processor cache line size set to 32 bytes.
File stride size set to 17 * record size.

测试结果除了表明 Intel SSD 的读写速度快得令人咋舌之外，还可以说明 Ext4 的各方面性能都超过了上一代 Ext3，甚至在大多数情况下，比没有日志功能的 Ext2 还要快出不少：

  reclen   write   rewrite   read   reread   random read   random write   bkwd read   record rewrite   stride read   fwrite   frewrite   fread   freread  
Ext2

real 28m12.718s
user 0m10.725s
sys 5m8.265s   4   218,680   216,596   630,248   245,802   88,700   138,065   106,112   1,882,623   73,538   214,175   218,364   566,570   247,381  
8   215,308   218,690   556,064   246,260   154,680   150,052   188,397   2,462,367   130,896   217,157   216,647   583,808   248,397  
16   216,457   216,843   575,046   245,701   258,660   158,750   306,842   2,654,320   220,939   216,061   218,140   598,174   246,581  
32   217,925   214,289   537,976   243,081   394,013   167,002   464,240   2,397,831   340,775   217,434   219,353   583,463   246,341  
64   215,460   219,256   527,919   244,362   503,227   162,917   609,546   2,546,079   456,243   216,875   217,692   571,707   244,264  
128   219,081   216,173   540,831   242,526   609,750   161,442   721,701   2,656,729   551,122   217,780   217,427   579,271   242,291  
256   216,091   217,631   565,111   245,157   654,274   173,955   870,547   2,574,261   634,835   216,638   219,693   563,735   247,101  
Ext3

real 27m42.449s
user 0m11.529s
sys 7m17.049s   4   218,242   213,039   482,132   243,986   88,007   156,926   105,557   1,540,739   75,010   216,028   216,432   522,704   243,385  
8   218,390   217,915   544,892   244,979   152,424   190,454   181,486   1,945,603   130,737   218,364   216,431   530,853   243,222  
16   218,083   217,683   561,038   244,506   255,244   200,032   300,212   2,096,495   221,329   216,930   216,661   514,177   244,069  
32   216,258   217,013   569,246   243,811   389,745   198,275   446,462   1,934,853   338,785   216,809   219,296   530,634   243,446  
64   218,850   217,711   577,529   243,725   497,689   201,693   589,535   2,036,412   450,449   219,387   214,900   514,353   244,809  
128   220,234   215,687   530,519   241,615   608,244   199,619   714,295   1,992,168   553,022   217,828   218,454   513,596   241,510  
256   216,011   220,188   592,578   242,548   642,341   199,408   834,240   2,092,959   624,043   217,682   218,165   529,358   242,878  
Ext4

real 27m3.485s
user 0m10.847s
sys 6m9.578s   4   221,823   216,992   532,488   273,668   85,210   183,195   103,036   1,862,817   74,781   225,841   220,620   523,799   272,848  
8   226,028   218,580   561,960   272,036   154,972   216,505   178,482   2,135,372   132,506   227,423   215,766   641,021   271,328  
16   222,241   217,746   547,548   270,895   260,899   223,895   295,288   2,095,966   223,135   226,055   216,210   621,287   273,475  
32   220,121   213,025   240,426   247,628   345,210   175,977   451,631   2,145,351   342,236   225,796   213,427   598,331   269,759  
64   223,983   214,437   308,696   551,577   754,941   225,897   523,130   2,218,016   448,086   227,030   214,706   582,795   272,323  
128   222,576   217,816   624,636   271,293   644,500   224,997   720,468   2,308,315   582,943   225,971   217,373   552,335   274,237  
256   221,202   222,238   541,685   270,898   671,748   228,085   845,494   2,215,381   643,715   225,411   219,166   580,066   273,342