Re: [patch] Re: Does XFS prevent disk spindown?

Thor Kristoffersen
2008-04-10T00:33:20Z

David Chinner <dgc@sgi.com> writes:
> On Tue, Apr 08, 2008 at 07:53:13AM +0200, Thor Kristoffersen wrote:
>> David Chinner <dgc@sgi.com> writes:
>> >> > What does 'xfs_logprint -t' show in these "idle" states
>> >> > after these writes?
>> >>
>> >> xfs_logprint produces output like the one shown below, so it does indeed
>> >> look like it's writing to the journal. But why should it need to keep
>> >> writing to the journal when there have been no updates to any files on that
>> >> partition recently?
>> >
>> > Are you using lazy-count=1? (i.e. output of 'xfs_info <mtpt>', please).
>>
>> Looks like I am:
>>
>> meta-data=/dev/sda3 isize=256 agcount=4, agsize=42676171 blks
>> = sectsz=512 attr=2
>> data = bsize=4096 blocks=170704681, imaxpct=25
>> = sunit=0 swidth=0 blks
>> naming =version 2 bsize=4096
>> log =internal bsize=4096 blocks=32768, version=2
>> = sectsz=512 sunit=0 blks, lazy-count=1
>> realtime =none extsz=4096 blocks=0, rtextents=0
>>
>> Is that what's causing it? I have never specified any lazy-count option
>> when I created or mounted the filesystem. I didn't even know it existed.
>
> Introduced in 2.6.22, and recently was made the default mkfs config.
>
> Try the patch below.

Thanks a lot, David! Your patch worked perfectly. Also thanks to the
others who helped me track down this issue.

BTW, what are the consequences of setting lazy-count to 0? Less safety?
Reduced performance?

Thor