Check relatime setting in image

[RichardHightower]

Filesystems & Mount options & other urban legends Cassandra relies on a standard filesystem for storage. The choice of filesystem and how it's configured can have a large impact on performance.

One common performance option that I find amusing is the noatime option. It used to bring large gains in performance by avoiding the need to write to inodes every time a file is accessed. Many years ago, the Linux kernel changed the default atime behavior from synchronous to what is called relatime which means the kernel will batch atime updates in memory for a while and update inodes only periodically. This removes most of the performance overhead of atime, making the noatime tweak obsolete.

Another option I've seen abused a few times is the barrier/nobarrier flag. A filesystem barrier is a transaction marker that filesystems use to tell underlying devices which IOs need to be committed together to achieve consistency. Barriers may be disabled on Cassandra systems to get better disk throughput, but this should NOT be done without full understanding of what it means. Without barriers in place, filesystems may come back from a power failure with missing or corrupt data, so please read the mount(8) man page first and proceed with caution.