Date: Fri, 18 Jan 2013 13:22:27 -0700 From: Scott Long <scott4long@yahoo.com> To: Dieter BSD <dieterbsd@gmail.com> Cc: freebsd-hackers@freebsd.org, gibbs@FreeBSD.org, scottl@FreeBSD.org, mjacob@FreeBSD.org Subject: Re: IBM blade server abysmal disk write performances Message-ID: <6C0B86E6-195C-4D35-AE40-3D2F9F6D28FB@yahoo.com> In-Reply-To: <CAA3ZYrBV9f%2BcHx4jvS0UKTr%2Bp7eNUBA0S2%2Bv9oZAHqwm9VBOWw@mail.gmail.com> References: <CAA3ZYrBV9f%2BcHx4jvS0UKTr%2Bp7eNUBA0S2%2Bv9oZAHqwm9VBOWw@mail.gmail.com>
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On Jan 18, 2013, at 1:12 PM, Dieter BSD <dieterbsd@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
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