Re: [PATCH 00/23] per device dirty throttling -v8

Ingo Molnar
2007-08-05T17:55:47Z

* Theodore Tso <tytso@mit.edu> wrote:

> If you are always reading from the same small set of files (i.e., a
> database workload), then those inodes only get updated every 5 seconds
> (the traditional/default metadata update sync time, as well as the
> default ext3 journal update time), it's no big deal. Or if you are
> running a mail server, most of the time the mail queue files are
> getting updated anyway as you process them, and usually the mail is
> delivered before 5 seconds is up anyway.
>
> So earlier, when Ingo characterized it as, "whenever you read from a
> file, even one in memory cache.... do a write!", it's probably a bit
> unfair. Traditional Unix systems simply had very different workload
> characteristics than many modern dekstop systems today.

yeah, i didnt mean to say that it is _always_ a big issue, but "only a
small number of files are read" is a very, very small minority of even
the database server world.

Ingo