Redhat says in some of their docs

Page cache is a disk cache which holds data of files and executable programs, for example pages with actual contents of files or block devices. Page cache (disk cache) is used to reduce the number of disk reads. To control the percentage of total memory used for page cache in Red Hat Enterprise Linux 5, change the pagecache kernel parameter. The lower the percentage, the more the system favors reclaiming unmapped pagecache memory over mapped memory. High values (like the default value of 100) are not recommended for databases.

It points to /proc/sys/vm/pagecache to change that value.

I'm wondering what that is called in Ubuntu?

1 Answer 1


Nothing, I suspect. A glance at kernel version 2.6.18's Documentation/sysctl/vm.txt and Documentation/filesystems/proc.txt shows no such parameter, so it must be something patched in by Red Hat. Note that the docs you're referring to is for RHEL5, which is now 10 years old. This paywalled RHEL article suggests that that parameter was dropped in the next version. Presumably whatever it was they patched was deemed no longer worth the effort.

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