vmstat显示的buffer和cache的区别
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??Try the manual first.??$ man vmstat?? ...
?? Memory
?????? swpd: the amount of virtual memory used (kB).
?????? free: the amount of idle memory (kB).
?????? buff: the amount of memory used as buffers (kB).
?????? [红帽子8.0的Man中没有这一行]
?????? cache: the amount of memory used as cache.
??? ...?? See what's on my Red Hat Linux server.? $ vmstat?? procs????????????????????? memory??? swap????????? io???? system???????? cpu
?r? b? w?? swpd?? free?? buff? cache? si? so??? bi??? bo?? in??? cs? us? sy? id
?0? 0? 0????? 0 316488 159612 493916?? 0?? 0???? 0???? 6?? 22??? 23? 13?? 2? 14?Answers Googled:? To answer your question, buffers are only used for file metadata (inodes, etc) and data from raw block devices. It's accessed via block device and block number.
? Cache has file data blocks, and memory mapped information (i.e. files mapped with mmap() calls). It's accessed primarily via inode number.
? So, the main difference would be scope, I guess. One's more concerened with blocks on a device, the other with information in a file.? Either buffer can flush to disk, however. The buffer to the device file and the cache through the file system layer to the block device.????参考资料:1.?Red Hat Manuals2.?Linux Memory Management3.?System Performance Tuning, 2nd Edition, read?Chapter 4 Memory?online.??? or buy Chinese edition from?china-pub.http://blog.china-pub.com/more.asp?name=uniware&id=5345
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