关于AIX文件系统性能

root521

我想请问AIX文件系统性能有没有办法调优至接近裸设备性能？
有方法吗？

mike79

JFS2+CIO
AIO

ops

cio是并发io模式，类似裸设备的话还有dio，mount时可以用 mount -o设置
cio
                   Specifies the file system to be mounted for concurrent readers and writers. I/O on files in this filesystem
                   will behave as if they had been opened with O_CIO specified in the open() system call. Using this option will
                   prevent access in any manner other than CIO. It is impossible to use cached I/O on a filesystem mounted with
                   the cio option. This means that mapping commands such as mmap() and shmat() will fail with EINVAL when used on
                   any file in a filesystem mounted with the cio option. One side-effect of this is that it is impossible to run
                   binaries out of a cio mounted filesystem, since the loader may use mmap().

dio
                   Specifies that I/O on the filesystem will behave as if all the files had been opened with O_DIRECT specified in
                   the open() system call. Note: Using the -odio or -ocio flags can help performance on certain workloads, but
                   users should be aware that using these flags will prevent file caching for these file systems. Because
                   readahead is disabled for these file systems, this may decrease performance for large sequential reads.

[ 本帖最后由 ops 于 2008-10-30 10:08 编辑 ]

root521

那这样的mount能够大幅度提升文件系统性能吗？接近RAW设备性能吗？

ops

人家IBM说是可以达到接近裸设备的性能，它绕过了文件系统的cache，没有预读、回写之类的特性