If HTTP access is logged, follow these guidelines for the disk:
Write access logs on faster disks or attached storage.
If running multiple instances, move the logs for each instance onto separate disks as much as possible.
Enable the disk read or write cache. Note that if you enable write cache on the disk, some writes can be lost if the disk fails.
Consider mounting the disks with the following options, which can yield better disk performance: nologging, directio, noatime.