Re: [ext3] kjournald writing after each read despite noatime,commit=nnn

From: Dave Johnson
Date: Thu Jan 01 2009 - 14:35:40 EST


Dave Johnson writes:
> Bart Samwel writes:
> > This looks like it's a generic property of syncing an ext3 file system.
> > Try turning off laptop_mode and then running "sync". You will probably
> > see the same behaviour.
>
> yep, every sync() causes a gratuitous write to disk N seconds later
> even when no data has been read or written since the last sync().

Woops, correction, every sync() call causes a single gratuitous write,
no delay.

$ for n in 1 2 3 4 5; do sync; done

Jan 1 14:32:54 gw kernel: kjournald(760): WRITE block 2682 on hda1
Jan 1 14:32:54 gw kernel: kjournald(760): WRITE block 2684 on hda1
Jan 1 14:32:54 gw kernel: kjournald(760): WRITE block 2686 on hda1
Jan 1 14:32:54 gw kernel: kjournald(760): WRITE block 2688 on hda1
Jan 1 14:32:54 gw kernel: kjournald(760): WRITE block 2690 on hda1

--
Dave
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