Date: Sun, 3 Apr 2011 04:03:51 -0700 From: Jeremy Chadwick <freebsd@jdc.parodius.com> To: "Patrick M. Hausen" <hausen@punkt.de> Cc: mav@freebsd.org, FreeBSD Stable <freebsd-stable@freebsd.org> Subject: Re: ahci.ko in RELENG_8_2, what about atacontrol cap? Message-ID: <20110403110351.GA30312@icarus.home.lan> In-Reply-To: <3B6BFB01-3AC4-432B-8713-6CED09FFF9A2@punkt.de> References: <EFA22697-4025-4E8B-B20A-C0142926FE1F@punkt.de> <20110402094038.GA3521@icarus.home.lan> <3B6BFB01-3AC4-432B-8713-6CED09FFF9A2@punkt.de>
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On Sun, Apr 03, 2011 at 12:21:55PM +0200, Patrick M. Hausen wrote: > Hello, > > Am 02.04.2011 um 11:40 schrieb Jeremy Chadwick: > > You want "camcontrol identify adaX". DO NOT confuse this with > > "camcontrol inquiry adaX" (this won't work). > > > > identify = for ATA > > inquiry = for SCSI > > Works perfectly, but I just noticed one really odd thing: > > 1. boot without ahci.ko: > > nas-pmh# atacontrol cap ad4 > ... > write cache yes yes > > > 2. boot with ahci.ko: > > nas-pmh# camcontrol identify ada0 > ... > write cache yes no > > > Well? ;-) The system is a HP NL36 - I just found a couple > of articles mentioning that the default setting in the BIOS > setup was write cache disabled. I can check that in the > next couple of days when I take the machine back to the > lab (no monitor/keyboard at my home office). > > I'd prefer a way to make sure write cache is enabled via > some tuning from FreeBSD. The disks are dedicated to > a raidz2, so from what I found around the net, write cache > should not pose a major problem. Of course, one will lose > _some_ data at a power outage - what I want to avoid > for home office use is a completely lost file system. > Losing the last time machine backup of my Mac is tolerable. I don't have an explanation for what you're seeing. I can't reproduce it on any of our Supermicro systems (ICH9R-based, backed by a multitude of disk types; Intel X25-M and X25-V SSDs, WD Caviar Black 750GB, 1TB, and 2TB, etc.). CC'ing mav@ who might have some ideas. I don't see anything in RELENG_8 that looks relevant (just went through src/sys/dev/ahci's commit log). Alexander, disk type is here (Seagate ST32000542AS): http://lists.freebsd.org/pipermail/freebsd-stable/2011-April/062142.html -- | Jeremy Chadwick jdc@parodius.com | | Parodius Networking http://www.parodius.com/ | | UNIX Systems Administrator Mountain View, CA, USA | | Making life hard for others since 1977. PGP 4BD6C0CB |
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