Tuning the memory subsystem
It’s a bit strange that how Linux deals with memory can have a major say in disk performance memory. As already explained, the default behavior of the kernel works well in most cases. However, as they say, an excess of everything is bad. Frequent caching can result in a few problematic scenarios:
- When the kernel has accumulated a large amount of data in the page cache and eventually starts to flush that data onto disk, the disk will remain busy for quite some time because of the excessive write operations. This can adversely affect the overall I/O performance and increase disk response times.
- The kernel does not have a sense of the criticality of the data in the page cache. Hence, it does not distinguish between important and unimportant I/O. The kernel picks whichever block of data it deems appropriate and schedules it for a write or read operation. For instance, if an application performs both background and foreground I/O operations...
