IBM blade server abysmal disk write performances

[Scott Long]

On Jan 18, 2013, at 1:12 PM, Dieter BSD <dieterbsd at gmail.com> wrote:
> It is inexcusable that FreeBSD defaults to leaving the write cache on
> for SATA & PATA drives.

This was completely driven by the need to satisfy idiotic benchmarkers,
tech writers, and system administrators.  It was a huge deal for FreeBSD
4.4, IIRC.  It had been silently enabled it, we turned it off, released 4.4,
and then got murdered in the press for being "slow".

If I had my way, the WC would be off, everyone would be using SAS,
and anyone who enabled SATA WC or complained about I/O slowness
would be forced into Siberian salt mines for the remainder of their lives.


>  At least the admin can easily fix this by
> adding hw.ata.wc=0 to /boot/loader.conf.  The bigger problem is that
> FreeBSD does not support queuing on all controllers that support it.
> Not something that admins can fix, and inexcusable for an OS that
> claims to care about performance.

You keep saying this, but I'm unclear on what you mean.  Can you
explain?

Scott