Re: Is there a way to keep the 2.6 kjournald from writing to idledisks? (to allow spin-downs)
From: Nick Piggin
Date: Mon Jan 26 2004 - 05:44:32 EST
Lutz Vieweg wrote:
Felipe Alfaro Solana wrote:
On Sun, 2004-01-25 at 19:29, Lutz Vieweg wrote:
I run a server that usually doesn't have to do anything on the local
filesystems,
it just needs to answer some requests and perform some computations
in RAM.
So I use the "hdparm -S 123" parameter setting to keep the (IDE)
system disk from
spinning unneccessarily.
Alas, since an upgrade to kernel 2.6 and ext3 filesystem, I cannot
find a way to
let the harddisk spin down - I found out that "kjournald" writes a
few blocks every
few seconds.
As I wouldn't like to downgrade to ext2: Is there any way to keep
the 2.6 kjournald
from writing to idle disks?
I cannot see a good reason why kjournald would write when there are
no dirty buffers -
but still it does.
Have you tried playing with the laptop-mode patch? It's already in the
-mm kernel tree from Andrew Morton. I've been playing with it a little
(just a few minutes) and seems keep the disks spun down for some time.
This "laptop-mode" patch would make things far worse than they're now:
Spinning
up the disk about every 10min would reduce their lifetime
significantly instead
of extending it.
It's not a laptop, but a server with an ordinary 3.5" harddisk I'm
speaking about,
my goal is not saving power, but spinning down a harddisk that does
not need to
spin up the whole day long.
What I'm questioning is whether there's a need to write to idle disks
at all -
does anybody know why kjournald writes data even if there is nothing
to commit at all?
Because you aren't using the noatime option?
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