Date: Thu, 4 Feb 2010 13:46:20 +0100 (CET) From: Oliver Fromme <olli@lurza.secnetix.de> To: freebsd-hackers@FreeBSD.ORG, wblock@wonkity.com, alexbestms@wwu.de, jkim@FreeBSD.ORG Subject: Re: Spin down HDD after disk sync or before power off Message-ID: <201002041246.o14CkK39012628@lurza.secnetix.de> In-Reply-To: <alpine.BSF.2.00.1002031328060.9787@wonkity.com>
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Warren Block wrote: > Oliver Fromme wrote: > > Alexander Best wrote: > > > imo this patch takes good care of the problem. would be nice to > > > have it in HEAD. > > > > No -- *Please* make sure that the disks are only spun down > > upon an actual power-off command (i.e. when reboot() is > > called with the RB_POWEROFF flag). In all other cases the > > disks should keep running. It's not good to have the disks > > spin down and then immediately spin up again on every > > reboot. > > Could you elaborate a little on why that's bad? It seems like it would > be similar to a standby/resume action. While notebook disks are usually optimized to handle a high number of start/stop cycles, this isn't true for normal desktop or server disks, especially ones that are meant for continuous operation (24/7). This varies greatly between vendors and models, though. The point is that I defintitely wouldn't want to waste a start/stop cycle when it's not necessary. Also, it would be nice to have a way to disable the STANDBY command alltogether for people who don't want it. This could easily be implemented with a sysctl. > Are there any other device drivers that differentiate the reboot and > poweroff actions that could be used as inspiration or simply shamelessly > copied in modifying ata-disk? I'm sorry, I don't know. If the ad_shutdown() function doesn't have easy access to the boot "howto" variable, maybe the information could be stored in a kenv variable? Best regards Oliver -- Oliver Fromme, secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing b. M. Handelsregister: Registergericht Muenchen, HRA 74606, Geschäftsfuehrung: secnetix Verwaltungsgesellsch. mbH, Handelsregister: Registergericht Mün- chen, HRB 125758, Geschäftsführer: Maik Bachmann, Olaf Erb, Ralf Gebhart FreeBSD-Dienstleistungen, -Produkte und mehr: http://www.secnetix.de/bsd I suggested holding a "Python Object Oriented Programming Seminar", but the acronym was unpopular. -- Joseph Strout
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