Messages in this thread | | | From | Russell King <> | Subject | Re: sync: why disk cannot spin down | Date | Sun, 30 Jul 2000 23:37:33 +0100 (BST) |
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Xuan Baldauf writes: > this problem is possibly unrelated to reiserfs but related to > linux-kernel, but now I can prove it: regular sync()s do prevent the > spindown of (IDE) disks. There will be a call to sync() after 32 or less > seconds have elapsed since the last sync(). Not a problem itself, but > every sync spins up the disk again.
You may want to have a look at the atime/diratime mount options, or even chattr -A to prevent certain files causing a write when they're run/read.
Note that just executing "sync" causes its atime to be marked for update, which will cause a write back to disk a short while later.
What I tend to do is to partition my system in such a way that / and /usr can be mounted noatime (ie, all programs), /home is without any extra options, and /var with nodiratime. Eg:
/dev/hda3 on / type ext2 (rw,noatime) proc on /proc type proc (rw) /dev/hda4 on /usr type ext2 (rw,noatime) /dev/hda5 on /var type ext2 (rw,nodiratime) /dev/hda8 on /home type ext2 (rw)
Oh, I also set sshd to recreate its keys every 6 hours, and modify cron so it doesn't log to file (there doesn't seem to be a command line option for this).
With all this, I can get my machines (setup the way I have them) to run for up to 6 hours without spinning up the drives (ie, over night). Oh, the other thing is that I have set the standby timer on the hard drive (hdparm -S) to be 10 minutes, which means its not spinning down during my normal use.
Note that if you run stuff like xntpd, or squid, then it gets harder, but its still possible to achieve. _____ |_____| ------------------------------------------------- ---+---+- | | Russell King rmk@arm.linux.org.uk --- --- | | | | http://www.arm.linux.org.uk/~rmk/aboutme.html / / | | +-+-+ --- -+- / | THE developer of ARM Linux |+| /|\ / | | | --- | +-+-+ ------------------------------------------------- /\\\ |
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