Theo, does that then imply that setting the writeback time to the
journal commit time (5 seconds) would also largely eliminate the
How much of the benefit of delayed allocation do we lose by waiting a
couple seconds rather than minutes or tens of seconds? Any large
write could easily be happening over a longer period than any
reasonable writeback time, and so those cases should already be
allocating their eventual size immediately (think torrents or a long
running file copy).
On Thu, Mar 12, 2009 at 4:21 PM, Theodore Ts'o <email address hidden> wrote:
> So you can change the journal commit interval from 5 seconds to say 30
> seconds, or 600 seconds. Laptop mode for example will by default change
> the journal commit time to 30 seconds. That will do part of what you
> want; if you make the journal commit interval much larger than the
> default writeback time, that will achieve most of what you want.
> However, various disk buffers will get pinned in memory until the commit
> takes place, so extending commits may end up chewing up more memory used
> by the kernel. TNSTAAFL.