On Tue, 8 Mar 2005, Tobias Hofmann wrote:
[...]
I had found postings on the net claiming that doing so without unmounting the fs on the raid, this would lead to bad things happening - but your report seems to prove them wrong...
I've been using something called noflushd on a couple of small "home servers" for a couple of years now to spin the disks down. I made a posting about it here some time back and the consensus seemed to be (at the time) that it all should "just work"... And indeed it has been just working.
Thanks for mentioning this...
They are only running RAID-1 though, 2.4 and ext2. I understand the ext3 would force spin-up every 5 seconds which would sort of defeat it. There are other things to be aware of to (things that will defeat using hdparm) - making sure every entry in syslog.conf is -/var/log/whatever (ie. with the hyphen prepended) to stop if doing the fsync on every write which will spin up the disks. They are on UPSs, but they have been known to run-out in the past )-: so a long fsck and some data loss is to be expected.
Essentially noflushd blocks the kernel from writing to disk until memory fills up.. So most of the time the box sits with the disks spun down, and only spins up when we do some file reading/saving to them.
...and this is no prob for me, as my idea is to only spin down a raid used for data, not OS...
Noflushd is at http://noflushd.sourceforge.net/ and claims to work with 2.6, but says it will never work with journaling FSs like ext3 and XFS. (which is understandable)
...true, but bites me. I,ll still look into it, once I am free to fool around with the raid (which currently is a backup, so I,d hesitate to "kill" it... :)
greets, tobi... :) - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
