Subject: Re: running *without* softdep unsafe?
To: None <firstname.lastname@example.org>
From: Peter Seebach <email@example.com>
Date: 05/25/2000 11:02:08
In message <Pine.NEB.firstname.lastname@example.org>, Todd
>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.