Helix Core Server Administrator Guide: Fundamentals (2019.2)

Disk subsystem

For I/O requests that must be satisfied from beyond the filesystem cache, we recommend that:

  • The storage subsystem containing the db.* files have a memory cache, and that it be maximized.
  • Write-back caching be enabled, which requires that the storage subsystem’s memory have battery backup power.
  • I/O latency to the logical drive where the db.* files are located be minimized, including the rotational latency of the physical drives. Minimizing I/O latency might require direct connections between the host and the storage subsystem, and usually requires physical drives with the fastest rotational speed (such as 15K RPM).

Tip

Concerning solid state drives (SSDs), see "Disk Performance" in the Knowledge Base article, "Recommended Server Hardware Configurations".

RAID 1+0 (or RAID 10) is recommended for the logical drive where the db.* files are located. Generally, p4d performance improves as the number of physical drives in the logical drive increases. For a given amount of disk space required, better performance might result from using more smaller-capacity physical drives. The optimal stripe size might depend upon the number of physical drives in the logical drive.

Hardware-based RAID implementations usually have good performance characteristics. Software-based RAID implementations can require CPU cycles that could otherwise be used for p4d processes.