Subject: Re: running *without* softdep unsafe?
To: None <>
From: Peter Seebach <>
List: current-users
Date: 05/25/2000 11:02:08
In message <>, Todd 
Vierling writes:
>We are no longer building update(8) as part of the distribution.  Doesn't
>this assume that the admin _is_ using the [GPL'd] softdep?  After all,
>update(8)'s purpose is to call sync() every 30 seconds or so to keep the
>data blocks and metadata as up-to-date as possible.

As I understand it, no; even if you're not using soft updates, you're using
the associated "trickle-sync" code, which does updates slowly over time

>Extreme case:  Let's say I have a non-softdep system, under very light load,
>and issue a write() to a file.  It's buffered, of course, so the buffer
>cache (page cache?  Are we doing UBC in the trunk yet?) is holding on to the
>data.  _Nothing_ in userland happens for another 30 minutes--in particular,
>sync() or write() are not called again--and the system loses power.  Would
>that write() ever have made it to disk for sure?

I'm not sure, but I believe it does.