Subject: Re: Interactive responsiveness under heavy I/O load
To: Johan A. van Zanten <johan@giantfoo.org>
From: Alfred Perlstein <bright@mu.org>
List: netbsd-users
Date: 01/26/2004 12:53:53
* Johan A. van Zanten <johan@giantfoo.org> [040126 12:13] wrote:
>
> John Goerzen <jgoerzen@complete.org> wrote:
>
>
> > Have I stumbled across the reason softdep is not enabled by default, or
> > is there some other logic behind this?
>
> My understanding of how soft dependencies works is that file system
> metadata is cached in memory for a short period of time (like 20
> seconds?), which means it's at risk (of being lost) if the machine were to
> loose power. The mount man page also says that it's gone through "moderate
> to heavy testing, but should still be used with care."
That's the same as with any other filesystem that has safe meta
data handling, journalling systems included. Your data is not
guaranteed to be there unless you fsync it.
--
- Alfred Perlstein
- Research Engineering Development Inc.
- email: bright@mu.org cell: 408-480-4684