Date: Tue, 14 Feb 2012 23:39:28 +0100 From: Oscar Prieto <oscarmpp@googlemail.com> To: Jeremy Chadwick <freebsd@jdc.parodius.com> Cc: Harald Schmalzbauer <h.schmalzbauer@omnilan.de>, freebsd-stable@freebsd.org, Martin Sugioarto <martin@sugioarto.com>, Claudius Herder <claudius@ambtec.de> Subject: Re: problems with AHCI on FreeBSD 8.2 Message-ID: <CAK9wqRqU_DSFTYODtwbV6hbs4vqF2MXY3f0DTba-TDRqq9e4zA@mail.gmail.com> In-Reply-To: <20120214203123.GA5959@icarus.home.lan> References: <20120214100513.GA94501@icarus.home.lan> <20120214135435.GQ2010@equilibrium.bsdes.net> <20120214141601.GA98986@icarus.home.lan> <4F3A83DE.3000200@ambtec.de> <20120214165029.GA1852@icarus.home.lan> <4F3A971F.9040407@omnilan.de> <20120214192319.44ff7aff@zelda.sugioarto.com> <4F3AB4F0.9010002@omnilan.de> <20120214205143.2a6b9c87@zelda.sugioarto.com> <CAK9wqRqR3KMUDchFs9L5bVV_CZUF_DEAx_i_Rp5StAa_%2BdGbGw@mail.gmail.com> <20120214203123.GA5959@icarus.home.lan>
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Thank you again Jeremy, sure it helps! On Tue, Feb 14, 2012 at 9:31 PM, Jeremy Chadwick <freebsd@jdc.parodius.com> wrote: > On Tue, Feb 14, 2012 at 09:19:02PM +0100, Oscar Prieto wrote: >> Thank you Jeremy, i'm already checking your links. >> >> When i installed smartd i configured a daily short test and a weekly >> long one for all the drives while the machine remains mostly unused, >> never thought it could be a problem reading the documentation and info >> around. >> >> # /usr/local/etc/smartd.conf >> /dev/ada0 -a -o on -S on -s (S/../.././03|L/../../2/07) >> /dev/ada1 -a -o on -S on -s (S/../.././04|L/../../3/07) >> /dev/ada2 -a -o on -S on -s (S/../.././05|L/../../4/07) >> /dev/ada3 -a -o on -S on -s (S/../.././06|L/../../5/07) > > The problem is that, quite honestly, these do you zero good. =A0All it do= es > is make a mess (per se) of the SMART self-test log. > > Take for example your situation with ada3: smartd(8) told you that the > number of pending sectors increased to 5, and uncorrected increased to > 1. =A0That's really all you need to know at that point. =A0If you want to > know the LBA numbers which are problematic, you can manually intervene. > > The point is: the drive itself is going to notice problematic or bad > sectors quicker than periodic short or long or surface scan tests will. > Let the drive do its thing normally and only use SMART tests when > there's indication something is wrong. > >> I'll remove the checks, do you advice for removing the daemon altogether= ? > > smartd(8) is useful because it keeps track of attributes which change in > value and logs data to syslog (if I remember right), thus you have an > exact time/date when an attribute changed. =A0This is especially useful > for things pertaining to sector/physical media problems. > > As such, I tend to recommend folks using smartd(8) properly tune their > smartd.conf to only monitor specific attributes. =A0This varies from driv= e > to drive, but the key ones are things like attributes 5, 10, 11, 192, > 193, 194 (if you want temperature logging), 196, 197, 198, 199, and 200. > I'm speaking strictly for Western Digital disks here. > > The stock defaults, if I remember right, are to "monitor everything", > which really doesn't work well given that so many vendors encode their > RAW_VALUE fields in proprietary/vendor-specific formats. =A0People will > often monitor things like the Hardware_ECC_Recovered attribute and start > "freaking out" once day when the value goes from 0 to 838938239 or > something larger. =A0Attribute data formats are not part of the ATA > standard, so vendors choose to encode them. =A0Plus, not many admins that > I've run into (honest) know what that attribute actually means > disk-wise (hint: it's 100% normal for sector ECC to happen at all times; > magnetic media is not perfect, that's what the per-sector ECC section is > for!) > > However: people don't understand what SMART attribute acquisition > actually does behind the scenes -- it results in the disk having to read > from the HPA area (not user accessible or within LBA regions), which > means seeking + moving the arms to an area, reading, then reporting all > of this back. =A0Thus, it impacts I/O performance. =A0This is why I don't > use smartd(8) on any of our systems. =A0But if I was to use it? =A0I woul= d > have it poll maybe every 120 minutes, rather than every 30. =A0It all > depends on the system/load/etc.. =A0I've seen people poll every 5 minutes > (I think they're absolutely crazy/paranoid). =A0Their systems, their > problem. =A0:-) > > Hope this helps. > > -- > | Jeremy Chadwick =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0= =A0 =A0 jdc@parodius.com | > | Parodius Networking =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 http://www.= parodius.com/ | > | UNIX Systems Administrator =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 Mountain Vie= w, CA, US | > | Making life hard for others since 1977. =A0 =A0 =A0 =A0 =A0 =A0 PGP 4BD= 6C0CB | >
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