Re: Disk I/O slowness

> On Jul 30, 2026, at 9:32=E2=80=AFAM, Andy Smith <[email protected]> =
wrote:
>=20
> On Thu, Jul 30, 2026 at 07:17:01AM -0600, Casey Deccio wrote:
>> Seagate BarraCuda 5TB Internal Hard Drive HDD =E2=80=93 2.5 Inch SATA =
6Gb/s 5400 RPM 128MB
>=20
> 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.
>=20
> 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.
>=20
> 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?
>=20
> 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 for the info.  For this system I did optimize for cost, =
understanding that there would be some tradeoffs with regard to =
performance.  I didn't suspect that these issues were related to the =
drives because I have another setup using the same drives, and it =
doesn't have this same issue.  To be clear, it has these same drives and =
it is using a RAID5, but it's on a different motherboard using a =
MegaRAID controller with hardware RAID.

Thanks,
Casey=