Are large RAID stripe sizes useful with FreeBSD?
Ivan Voras
ivoras at freebsd.org
Mon Mar 31 15:48:15 PDT 2008
On 01/04/2008, Scott Long <scottl at samsco.org> wrote:
> TCQ is a protocol specific to parallel SCSI that involves the use of
> protocol messages and control signals found only on a parallel SCSI bus.
> PCI RAID controllers that present a SCSI interface to the OS don't use
> real TCQ to communicate between the OS and the controller. Even though
> these kinds of controllers use the SCSI command protocol, they still use
> a custom device-specific low-level communication protocol that handles
> the transfer and queuing of commands. External RAID
> controllers/enclosures do use the appropriate SCSI/SAS/FC/SATA bus
> queuing mechanism, but I'm not sure if that's what you're talking about
> here.
Your're right, I'm not. On further thought it's logical - if RAID
controllers talked plain SCSI to the OS there wouldn't be a need for
specific drivers, right?
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