Re: Disk I/O slowness

Hi,

On Thu, Jul 30, 2026 at 07:17:01AM -0600, Casey Deccio wrote:
> Seagate BarraCuda 5TB Internal Hard Drive HDD – 2.5 Inch SATA 6Gb/s 5400 RPM 128MB

Almost all high capacity 2.5" SATA drives are SMR (shingled magnetic
recording) and are really intended for use in laptops, not for serious
server purposes. I haven't checked this model but I would be very
surprised if it's not SMR, and the 5.4kRPM also suggests not for server
use.

SMR drives have a write cache and after this write cache is filled, the
write performance is absolutely terrible. A lot of people find them
unsuitable for use in RAID arrays (or zfs pools) because even the
periodic scrub can't complete in a reasonable time period.

This could easily explain the very low performance under write load
here. Have you used these models of drive before with a better
performance outcome?

Consumer-level SATA SSDs will definitely perform better though the cost
will be eye-watering (in comparison) for 3x ~4TB or 3x ~8TB. This is an
issue I have struggled with myself - very very hard to find decently
performing 2.5" SATA drives.

Thanks,
Andy