Final answer:
(E) Upgrade to a solid-state drive (SSD). To improve hard drive performance on a Linux server, maintaining ample free disk space and upgrading to an SSD are effective steps.
Step-by-step explanation:
To address the issue of a slow performing hard drive on a Linux server, two recommended steps are maintaining a healthy amount of free disk space on the drive and considering an upgrade to an SSD (solid-state drive). Keeping a considerable amount of disk space free is crucial as it allows the file system to have room for temporary files and to organize the existing data more efficiently, potentially reducing seek times.
Upgrading to a solid-state drive is another effective way to improve performance since SSDs offer faster data access times and better durability compared to conventional hard disk drives.
Option B, keeping the disk defragmented, is generally not as relevant for Linux file systems as it is for some Windows file systems such as NTFS, because file systems like ext4 used in Linux already incorporate strategies to minimize fragmentation. Option C, using a disk benchmark tool, might help you to confirm the performance issue but will not itself improve the performance. Lastly, Option D, disabling the page cache, is usually not recommended because the page cache is critical for reducing disk I/O by caching frequently accessed data.