Date: Thu, 05 Mar 2009 20:03:45 +0100 From: Tobias Blersch <abitos@abitos.org> To: Oliver Fromme <olli@lurza.secnetix.de> Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: Spin down HDD after disk sync or before power off Message-ID: <49B02211.1010809@abitos.org> In-Reply-To: <200903050758.n257wod8088426@lurza.secnetix.de> References: <200903050758.n257wod8088426@lurza.secnetix.de>
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Oliver Fromme wrote: > > Joerg Sonnenberger wrote: > > This is not true. Many hard disks don't like having to do an emergency > > shutdown as it affects the disk life time negatively. That's what > > happens if you poweroff the machine when the disks are still spinning. > > Can you point to any authoritative information (URL) about > that claim, such as vendor specs, white paper or similar? http://www.hitachigst.com/tech/techlib.nsf/techdocs/28DCCB17E0EEC5A086256F4E006E2F5B Thats the specification for my notebooks hard drive. Section 6.6 Reliability gives data about how to power-off the disk. It also contains numbers of supported load/unloads and emergency unloads. Emergency unloads are invoked when the heads are still loaded and power fails. > The product supports a minimum of 600,000 normal load/unloads. > The drive supports a minimum of 20,000 emergency unloads. Tobias
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