{"version":"1.0","provider_name":"Jui-Nan Lin's Blog","provider_url":"https:\/\/jnlin.org","author_name":"jnlin","author_url":"https:\/\/jnlin.org\/author\/jnlin\/","title":"FreeBSD: vfs.read_max for RAID","html":"

Tested with: bonnie -s 2048, FreeBSD 7.0 UFS2 , Hardware RAID 5 (6 PATA 7200rpm 250G disks)
vfs.read_max=8 (default)
<\/p>

             -------Sequential Output--------  
             -Per Char- --Block--- -Rewrite-- 
Machine   MB K\/sec %CPU K\/sec %CPU K\/sec %CPU   
        2048 25812 24.8 26483  6.6 13886  4.4   
             ---Sequential Input-- --Random--
             -Per Char- --Block--- --Seeks--- 
             K\/sec %CPU K\/sec %CPU  \/sec %CPU 
             32162 32.5 33386  5.1 232.3  1.5<\/code><\/p> <\/blockquote>

vfs.read_mas=128<\/p>

             -------Sequential Output--------
             -Per Char- --Block--- -Rewrite--
Machine MB   K\/sec %CPU K\/sec %CPU K\/sec %CPU 
        2048 25380 24.3 25949  6.5 13956  4.3  
             ---Sequential Input-- --Random--
             -Per Char- --Block--- --Seeks---
             K\/sec %CPU K\/sec %CPU  \/sec %CPU
             41060 43.4 42839  8.3 224.9  1.4<\/code>
             <\/code><\/p> <\/blockquote>

vfs.read_max=256 <\/p>

             -------Sequential Output--------
             -Per Char- --Block--- -Rewrite-- 
Machine   MB K\/sec %CPU K\/sec %CPU K\/sec %CPU 
        2048 25714 24.3 25939  6.5 13966  4.3  
             ---Sequential Input-- --Random-- 
             -Per Char- --Block--- --Seeks---
             K\/sec %CPU K\/sec %CPU  \/sec %CPU
             41442 43.8 43737 8.6  225.2  1.5 
        <\/code><\/blockquote>
<\/p>

\u7d50\u8ad6\uff1a\u8abf\u6574 vfs.read_max \u5c0d random \u5b58\u53d6\u7684\u6548\u80fd\u6c92\u6709\u592a\u5927\u5e6b\u52a9\uff0c\u800c\u5c0d sequential read access \u5247\u6709 25% \u7684\u6548\u80fd\u589e\u9032\u3002<\/p>","type":"rich"}