RAID 5 Speed Increase with More or Larger HDDs?

[Average Pro]

I've been trying to confirm or deny if a RAID 5 performance increases with more or larger drives. For this discussion, I am referring to HDDs so no SSDs. I recently purchased an 8-bay enclosure and plan to utilize 4, 5 or 6 of the bays for a RAID 5.

(1) Is there a performance increase read and/or write if I build the RAID with 6 HDDs as opposed to 4 HDDs?
(2) Is there a performance increase read and/or write if I utilize 6, 8, or 10 TB HDDs?
(3) What is the performance increase read and/or write between Western Digital Red Pro and WD Gold/Ultrastar?

I will utilized the RAID as the primary storage for photos for Adobe LR. When I turn on my MacPro, this is where LR will grab the photos from. The LR catalog and related files will be on an SSD. The connection from the MacPro to the enclosure will be via Thunderbolt 3. I will have backups of the enclosure on separate enclosures. The enclose is a QNAP TVS-872XT.

 

[Ledgem]

I've been trying to confirm or deny if a RAID 5 performance increases with more or larger drives. For this discussion, I am referring to HDDs so no SSDs. I recently purchased an 8-bay enclosure and plan to utilize 4, 5 or 6 of the bays for a RAID 5.

(1) Is there a performance increase read and/or write if I build the RAID with 6 HDDs as opposed to 4 HDDs?
(2) Is there a performance increase read and/or write if I utilize 6, 8, or 10 TB HDDs?
(3) What is the performance increase read and/or write between Western Digital Red Pro and WD Gold/Ultrastar?

I will utilized the RAID as the primary storage for photos for Adobe LR. When I turn on my MacPro, this is where LR will grab the photos from. The LR catalog and related files will be on an SSD. The connection from the MacPro to the enclosure will be via Thunderbolt 3. I will have backups of the enclosure on separate enclosures. The enclose is a QNAP TVS-872XT.

In theory, larger drives are more dense, meaning less physical distance needs to be traveled to reach various bits of data. I think I've seen studies on this one before.

In theory, having more drives means faster access times, because the data is spread across more drives that can seek independently of each other. I don't know for certain if I've seen that one studied before.

Which one makes the bigger difference? In a RAID system, having more drives probably has a greater performance benefit compared with having fewer, larger drives, although I have not seen concrete data on the comparison. More drives offers other benefits, though, such as the ability to more easily go to RAID 6 (double parity drives to protect against two drive failures) and to have faster rebuild times when swapping out drives.

NAS-optimized drives have a performance benefit over standard archive-based hard drives. I recall recently reading a comparison between Seagate IronWolf (NAS) drives versus Barracuda (standard desktop drives), and the IronWolf performance was superior. I think the conclusion was that it partly came down to differences in cache size.

Does any of this make a huge difference for photography-based purposes? Probably not. Even if you're working with huge image files the total data being accessed is pretty small overall, unless you're trying to zoom through a huge catalog. It would be a different story if working with video.