Re: FSFS vs BDB

On Thu, Nov 13, 2008 at 5:23 AM, Jan Hendrik <list.jan.hendrik_at_gmail.com> wrote:

> Two things keep us from switching to FSFS even just for a
> practical test period:
>
> -- Never touch a running system. And BDB runs now.

Definitely. (And you've probably been doing regular "svnadmin dump"
backups, so even if there were still corruption issues, you'd be able
to recover from them...)

> -- I don't like the idea of having thousands of folders with thousands
> of files each. It raises the chance of troubles and I guess one
> damaged file would make the repository as inaccessible as a
> corrupted DB file.

That, I'd have to take issue with - pre 1.5 you have *two* directories
with thousands of files each (you have a pair of files per *delta*, it
doesn't matter what your hierarchy looks like); in 1.5 with sharding,
you probably have hundreds but with only a thousand files each - and
they're *static*, none of these files are written to once created.
This is far less filesystem churn than, say, my personal photo gallery
produces :-) On top of that, the unix filesystem has had a lot more
scrutiny in a much wider range of cases than BDB itself ever will.

> Just my tuppence, I'm no expert in neither SVN nor BDB internals.

I've looked at them more closely than I'd hoped to (my name is on some
of the very early BDB bugfixes from the Kerberos days, which is one
reason I'm a little twitchy about it :-)

> All this with Windows 2K/XP as OS. Repository accessed per
> Apache 2.0.x on the LAN.

We use Debian and svn+ssh on an fsfs repository (18G/90k revisions, 5
years of development, 300+ branches, converted from CVS a few years
back.) Weekly full backups, nightly incrementals, plus an internal
forum that gets diff postings from mailer.py if we ever need to do any
severe recovery (we haven't - we test the backups regularly, but
haven't needed them.)

-- 
_Mark_ <eichin_at_thok.org> <eichin_at_gmail.com>
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