Date: Mon, 27 Oct 2008 20:50:44 +0100 From: martinko <gamato@users.sf.net> To: freebsd-stable@freebsd.org Subject: Re: Short SMART check causes disk op timeouts Message-ID: <ge562k$c3m$1@ger.gmane.org> In-Reply-To: <20081027191028.GA28688@icarus.home.lan> References: <4905951B.2050602@sh.cvut.cz> <20081027160828.GA24496@icarus.home.lan> <4905F8BB.3080302@sh.cvut.cz> <20081027175337.GA27175@icarus.home.lan> <ge52kh$uhv$1@ger.gmane.org> <20081027191028.GA28688@icarus.home.lan>
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Jeremy Chadwick wrote: > On Mon, Oct 27, 2008 at 07:52:01PM +0100, martinko wrote: >> Jeremy Chadwick wrote: >>>>>> Now, does the timeout cause loss of any data? Is there anything besides >>>>>> disabling the testing that I can do about it? >>>>> Do you understand what short and long offline tests actually do and what >>>>> they're used for? :-) If so, you'd know that running them periodically >>>>> is more or less silly (IMHO). >>>> I do not, not completely :) I think I have just copied the settings from >>>> somewhere and only just tweaked it a bit whenever I have added a disk. >>> Let me know if you figure out who or what online resource solicited >>> adding daily short/long tests, as I'd like to talk to them about their >>> decision. I have a feeling whoever thought it up felt that the tests >>> were performing entire sector scans of the entire disk, which is simply >>> not the case. >>> >> Hallo, >> >> Reading this thread I checked my config to find this: ;-) >> >> #/dev/ad0 -a -n standby,q -o on -S on -s (S/../.././02|L/../../7/03) -m >> root # ++ 2006-11-03 mato >> /dev/ad0 -a -o on -S on -s (S/../.././02|L/../../7/03) -m root # ++ >> 2006-11-03 mato >> >> I believe I came up with the settings after reading manual page / >> documentation of the tool. > > Can you explain why you're doing this? So far no one's provided a > reason *why* they're doing short and long offline scans on a daily > basis. I'm under the impression the conclusion was reached like this: > "man smartd.conf ... oh, -s, a neat thing, let's enable it". > > There are negative repercussions to doing tests of this nature at such > regular intervals. Once-a-week is borderline acceptable; once a month > would be quite reasonable. I'd love to know what kind of affect daily > tests have on MTBF; I can imagine it's reached much sooner with this. > > The main point of smartd is to monitor SMART attribute changes. If > you're concerned about the health of your hard disk, you should be > looking at your logs and not relying on things like automatic short/long > tests. Most SMART attributes are updated immediately and not during an > offline test, and all of those attribute changes will be logged. > You asked Miroslav about source of his configuration. And as it is very similar to mine I think we both have it from smartd documentation. Where else to look for information? It's a usual source. So if you think it's wrong please contact the authors, we're obviously just users. Thanks. M. PS: Btw, long offline scan is scheduled on weekly basis, not daily. If it's good or not I do not know.
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