Re:Backblaze Drive Stats for 2024
by pjdesno on Wednesday February 12, 2025 @10:33AM
(#43026359)
Um, no. Not unless you're still running ancient sub-1TB enterprise drives.
It turns out that modern hard drives have a specified workload limit [1] - this is an artifact of heads being positioned at a low height (<1nm) over the platter during read and write operations, and a "safe" height (10nm? more?) when not transferring data.
For an 18TB Exos X18 drive with a specified workload of 550TB read+write per year, assuming a lifetime of 5 years[2] and that you never actually read back the data you wrote, this would be at max about 150 drive overwrites, or a total of 2.75PB transferred.
In contrast the 15TB Solidigm D5-P5316, a read-optimized enterprise QLC drive, is rated for 10PB of random 64K writes, and 51PB of sequential writes.
[2] the warrantee is 5 years, so I assume "<550TB/yr" means "bad things might happen after 2.75PB". It's quite possible that "bad things" are a lot less bad than what happens after 51PB of writes to the Solidigm drive, but if you exceed the spec by 18x to give you 51PB written, I would assume it would be quite bad.
Re:Backblaze Drive Stats for 2024
by pjdesno on Wednesday February 12, 2025 @10:35AM
(#43026379)
ps: the white paper is old, I think head heights were 2nm back then. I'm pretty sure <1nm requires helium-filled drives, as the diameter of a nitrogen molecule is about 0.3nm
It turns out that modern hard drives have a specified workload limit [1] - this is an artifact of heads being positioned at a low height (<1nm) over the platter during read and write operations, and a "safe" height (10nm? more?) when not transferring data.
For an 18TB Exos X18 drive with a specified workload of 550TB read+write per year, assuming a lifetime of 5 years[2] and that you never actually read back the data you wrote, this would be at max about 150 drive overwrites, or a total of 2.75PB transferred.
In contrast the 15TB Solidigm D5-P5316, a read-optimized enterprise QLC drive, is rated for 10PB of random 64K writes, and 51PB of sequential writes.
[1] https://products.wdc.com/library/other/2579-772003.pdf
[2] the warrantee is 5 years, so I assume "<550TB/yr" means "bad things might happen after 2.75PB". It's quite possible that "bad things" are a lot less bad than what happens after 51PB of writes to the Solidigm drive, but if you exceed the spec by 18x to give you 51PB written, I would assume it would be quite bad.