Date: Tue, 21 Jul 2009 10:53:25 +0200 From: Mark Stapper <stark@mapper.nl> To: Ivan Voras <ivoras@freebsd.org> Cc: stable@freebsd.org Subject: Re: ZFS RAIDZ and atacontrol spindown settings Message-ID: <4A658205.5000709@mapper.nl> In-Reply-To: <9bbcef730907210137udf7f90ax21aa530ab859f8a6@mail.gmail.com> References: <4A643F5B.8080806@mapper.nl> <h421n2$1kt$1@ger.gmane.org> <4A656076.2060205@mapper.nl> <9bbcef730907210137udf7f90ax21aa530ab859f8a6@mail.gmail.com>
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This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig914F76917941DCE91CA31D30 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Ivan Voras wrote: > 2009/7/21 Mark Stapper <stark@mapper.nl>: > =20 >> Ivan Voras wrote: >> =20 >>> Mark Stapper wrote: >>> =20 >>>> Good day, >>>> >>>> I am the proud user of a FreeBSD 7.2 AMD64 system housing, amongst o= ther >>>> things, a data server. >>>> My "server"(It's called "Yoshi") runs FreeBSD from a mirrored system= >>>> disc, and has a zfs RAIDZ array with 4 discs for bulky data. >>>> As it is a home server, and I work during the day, these four discs = were >>>> spinning happily all day long without much use for them doing so. >>>> To save the world(and money) I issued the command "atacontrol spindo= wn >>>> 1800" for all the discs in my array spinning them down after thirty >>>> minutes of idle spinning. >>>> So far so good, me very happy! However, when I access the array afte= r >>>> the discs have been spun down, it spins up the discs one after the >>>> other... >>>> Mind you one AFTER the other, taking 4*9 seconds to do a "ls" comman= d on >>>> my music directory. >>>> Content as I am with the smooth down- and upspinning of the disks, I= >>>> would like it better if the four discs would spin up simultaneously.= >>>> Thus my question: "Is it possible to \"group\" discs to be spun up >>>> together, or to issue a custom command upon upspinning of a disc suc= h as >>>> to spin up other disks?" >>>> =20 >>> Good question but the answer is probably no - it really only depends >>> on how ZFS accesses the drives; if it accesses them in sequence, you >>> can't change it. >>> =20 >> I've been looking at writing a shell script which monitors >> /var/log/messages. >> something like: >> >> If last line in /var/log/messages is like "request while spun down. >> Starting." >> spinup disks >> >> couple of problems though, I should probably poll the kernel messages >> every second or so, but if I only check the last linee, I could miss t= he >> spinup message. >> I could count the number of lines in /var/log/messages and keep count = of >> the number of lines i've seen. Problem with this approach is that it's= >> not very efficient. >> So I was hoping there is a way to receive this kernel message directly= =2E >> I am now thinking in the lines of a program which received a signal on= >> new kernel messages available or something similar. >> >> Any thoughts? >> =20 > > You could do what "tail -f" does and simply hook a kqueue to get new > messages from the /var/log/messages file. > =20 I'll try that! thanks! --------------enig914F76917941DCE91CA31D30 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAkplggkACgkQN9xNqOOVnWCMWQCfRaZ+oTtkXIf9/FtJb8G4fN7z 1o8AoI1+0k9ANE7RzBrpOrZAtTqnCvOt =KYsW -----END PGP SIGNATURE----- --------------enig914F76917941DCE91CA31D30--
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