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

[Thor Kristoffersen <thorkr@gmail.com>]

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