db4 backend alternative

[Henk.Roose at cwi.nl]

Mark Hannessen wrote:

> On Monday 20 December 2004 23:25, you wrote:
> > Hi Mark,
> >
> > I'm looking for information as to how to convert from BDB4 to skiplist.
> 
> well, I don't have any real info or tools...

I used cvt_cyrusdb to convert my mailboxes.db and per-user .seen files to
skiplist. There was no need to copy any mail.

> I only had 4 mail adresses at that time so I just copied all the mail using 
> imap from my old to the new server. might be doable with 50 clients as 
> well... though it is very braindead. suppose you could also write a script in 
> perl to do it for you.
> 
> > I've finished with a new install of SASL, Cyrus IMAP, Postfix, MySQL,
> > Web-Cyradm. I followed a how-to doc from Luc de Louw
> > (www.web-cyradm.org). I've got the install completed and am in
> > authentication testing phase. It looks like things are running ok.
> > Recently, I've been paying attention to Berkeley DB complaints on the
> > Cyrus mailing lists. Frankly, they have me concerned. The mail server
> > I'm creating will be a corporate production mail server, but only
> > serving 50 clients and 80GB of mail storage. I thought now would be a
> > good time to possibly convert to skiplist before I populate the mail
> > server.
> >
> > Can you point me to any docs on how to accomplish this? Does it mean
> > recompiling SASL and IMAP, or is a config file change?
> 
> I added the following to my imapd.conf
> 
> annotation_db: skiplist
> duplicate_db: skiplist
> mboxlist_db: skiplist
> ptscache_db: skiplist
> quota_db: skiplist
> seenstate_db: skiplist
> subscription_db: skiplist
> tlscache_db: skiplist
> 
> this will make sure everything will be stored in skiplist databases.
> 
> > Pardon my 
> > ignorance, but what is skiplist? I'm having a hard time researching
> > because I don't know much about it.
> 
> I don't have any real knowledge about skiplist other then that it is a 
> database backend that seems to be used exclusively by cyrus imap.
> 
> > Any help is greatly appreciated.
> >
> > Thanks,
> >
> > Mark Butscher
> >
> > Mark Hannessen wrote:
> > > lol, so this thread is still running..
> > > been a while since I started it.
> > >
> > > I must say i am very pleased with skiplist, I have simulated a few
> > > hunderd crashes and it was able to recover every time. with db4 I had to
> > > pray for a succesfull restart or lose all my mail. (not kidding)
> > >
> > > the reason I switched to linux wasn't speed... because speed is cheap.
> > >
> > > it was stability and security.
> > >
> > > I think that in general people with few users won't care about the little
> > > random seek speed gain from db4, and people with many many many users
> > > would like to go to sleep at night, knowing that when they wake up there
> > > cyrus server is still having a good time handing mail over to users.
> > >
> > > I am not a technical dude, skiplist might be plain ugly, but from my
> > > perspective it works at what it is supposed to do. db4 fails that
> > > purpose.
> > >
> > > If I had to choose, skiplist would be the default a not db4. think about
> > > the bad impression it gives when new users see cyrus imap destroy all
> > > there mail before there eyes while doing a simple cyrus reboot. you would
> > > lose all faith in that product and switch to another one right?
> > >
> > > And the worst thing it that this isn't needed at all.
> > > cyrus is a good product. but people won't use it if they can't see that.
> > >
> > > regards from a happy cyrus user,
> > >
> > > Mark Hannessen
> > >
> > > On Friday 10 December 2004 13:18, you wrote:
> > >>Michael Sims wrote:
> > >>>Denny Schierz wrote:
> > >>>>Am Montag, den 22.11.2004, 22:51 +0000 schrieb Mark Hannessen:
> > >>>>>I am really wondering about this because I just can't seem to get
> > >>>>>db4 to run stable.
> > >>>>
> > >>>>same problem here. I have to delete once a week all db's (but
> > >>>>mailboxes.db). Otherwise i have timeouts and bouncing mails :-/
> > >>>
> > >>>Seriously, why don't you guys switch to skiplist and avoid the whole
> > >>>Berkeley DB mess?  I switched to skiplist for mailboxes.db, deliver.db,
> > >>>and the seen databases (on 2.1.x) about a year and a half ago and
> > >>> haven't had a problem since.  Berkeley DB
> > >>
> > >>Same here. Switched a year ago and not a worry in the world.
> > >>The only difference is that I'm using deliver with db3-nosync (as with
> > >>the tls_sessions) and the subscribed folders databases are flat files.
> > >>The rest is all skiplist.
> > >>
> > >>>may perform better in some situations, but IMHO it's not worth the
> > >>> hassle it brings. YMMV...
> > >>
> > >>Regards
> > >
> > > ---
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> ---
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Bye,
Henk

--
Henk Roose - Henk.Roose at cwi.nl
CWI - Centrum voor Wiskunde en Informatica
Centre for Mathematics and Computer Science
Amsterdam (NL)
---
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