----- Original Message -----
From: "Richard Elling" <[email protected]>
> I'd prefer to keep it as the actual rate not an enum or bool so if we
> look to make improvements in the future we have rotation rate of the
> device and dont have to implement yet another struct member to store
> this.
>
> An example of this could be calculate lower loads for vdevs with a higher
> rotational rate.
>
> To clarify as per ATA and SCSI specs:
> 0 = Rate unknown
> 1 = Rate non-rotationl
> 2-INT16_MAX = rotational rate
This doesn't seem future-proof to me. Today we know that 15k drives are going
EOL
and will not be replaced. We know that variable-speed drives are important for
low
power consumption. We also know that disks with a performance characteristic
as a function of rotation will also go away as the new technologies like shingles
further destroy the simple performance model we used for magnetic disks.
In other words, I think we should use some figure of merit for varying
performance, but
rotation isn't a good choice. Let's go ahead and abstract this today, even
though there
will be two choices for most people today: SSD vs HDD.
Thats the spec, so its what we have to go on ;-)
Regards
Steve
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