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Re: FSFS performance on NAS/NFS

From: Erik Huelsmann <ehuels_at_gmail.com>
Date: 2007-03-09 21:59:41 CET

On 3/9/07, Dave Camp <dave@thinbits.com> wrote:
> > Les Mikesell wrote:
> >> Nathan Kidd wrote:
> >>> I think that's a little unfair to BDB. Yes there are many reports of
> >>> "my BDB repo has 'crashed'", but invariably it is a result of new
> >>> users not understanding BDB's behaviour when an operation is
> >>> improperly interrupted ("wedging"). This has nothing to do with
> >>> "caring about your data" but ease of use with the server (i.e. data is
> >>> not lost, you just need to manually run 'svnadmin recover'). An more
> >>> experienced admin can set things up so this never becomes a problem.
> >>> New BDB's auto-recover from "wedging" so it isn't an issue at all any
> >>> more.
> >>
> >> I think a lot of people have had bad experiences with BDB in other
> >> contexts in the past, so it's going to take a while to trust that it is
> >> any better this time around.
> >
> > Can you recall specific cases?
> >
> > I've been on the users lists since 1.0 and only recall (with admittedly
> > non-ECC memory :) issues that could be described by "yes, BDB is more
> > difficult to administer, and this is a case where the user/admin screwed
> > up". E.g.
> > * improper access/permissions so repo gets wedged
> > (fixed with BDB 4.4)
> > * system upgrade messed up so wrong version of bdb libs found
> > (still possible, but I think package maintainers are generally more
> > conscientious after the initial problems)
> > * (early 1.0) BDB config max settings needed upping as repo grew
> > (fixed since ~1.1)
> >
> > I agree that for the average user FSFS is just a better choice because
> > it "just works" (hey, I use these days too :), but I'd hate to see the
> > legit BDB complaint "more difficult to set up right" turn into "this
> > thing can't be trusted" based on handwavy say-so alone.
>
> I was one of those people and it wasn't "handwavy say-so". At the time, a
> fresh out-of-the-box svn install with BDB would eventually corrupt the DB
> (not just the wedging issue). Although it appeared to work fine for most
> people, there was a decent number of reports of serious problems. The svn
> devs even admitted on list it was an issue with how they were using bdb.
>
> Maybe things are better these days. But my source code is much to valuable
> to ever try that again.

The issue with how subversion is using BDB had to do with wedging. Not
with real dataloss. There were versions of BDB which had some real
trouble (v4.1), but at that time 4.0 was still quite regular. Later
4.2+ was rock solid again.

HTH,

Erik.

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Received on Fri Mar 9 22:00:05 2007

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