kjournald進(jìn)程占用了大量CPU,如何優(yōu)化?

yj1804

主要運(yùn)行的是mysql 服務(wù)器, 數(shù)據(jù)操作非常頻繁, 發(fā)現(xiàn)運(yùn)行時(shí)間比較長(zhǎng)以后, kjournald占用了大量的CPU, 導(dǎo)致系統(tǒng)非常緩慢, 有什么優(yōu)化方式么?
文件系統(tǒng)使用的是ext3

meiki05

調(diào)整一下文件系統(tǒng)的jounal模式，默認(rèn)為ordered ，改成writeback會(huì)提高一些效率。

Despite writing some data more than once, ext3 is often faster (higher throughput) than ext2 because ext3's journaling optimizes hard drive head motion. You can choose from three journaling modes to optimize speed, optionally choosing to trade off some data integrity.

    * One mode, data=writeback, limits the data integrity guarantees, allowing old data to show up in files after a crash, for a potential increase in speed under some circumstances. (This mode, which is the default journaling mode for most journaling file systems, essentially provides the more limited data integrity guarantees of the ext2 file system and merely avoids the long file system check at boot time.)

    * The second mode, data=ordered (the default mode), guarantees that the data is consistent with the file system; recently-written files will never show up with garbage contents after a crash.

    * The last mode, data=journal, requires a larger journal for reasonable speed in most cases and therefore takes longer to recover in case of unclean shutdown, but is sometimes faster for certain database operations.

The default mode is recommended for general-purpose computing needs. To change the mode, add the data=something option to the mount options for that file system in the /etc/fstab file, as documented in the mount man page (man mount).

meiki05

另外可以用dumpe2fs看一下Journal size是多大，
可以想辦法把Journal size的值改大一些。