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

[Ingo Molnar]

* Theodore Tso <tytso@xxxxxxx> 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
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