Bug#342660: [Pkg-Cyrus-imapd-Debian-devel] Bug#342660: cyrus22-imapd: suggest making skiplist the default database backend for new installs

2005-12-09 Thread Etienne Goyer
I would second that.  BDB backend have been an endless source of
problems to me, and all my production installation are now skiplist.


Mark Nipper wrote:
> Package: cyrus22-imapd
> Version: 2.2.12-1
> Severity: wishlist
> Tags: patch
> 
> After recent problems upgrading from the 2.2.12 packages
> previously available from debian.speedblue.org which were using db3 to
> the new official packages using db4.2, I would suggest making the
> default backend for everything on a new installation skiplist over
> anything BDB.  There are seemingly known issues even using db4.3 and
> although I upgraded all of my existing db3 files to db4.2 using
> db4.2_upgrade, I still ended up having cyrmaster crash on me due to
> critical database errors.
> 
> This seems like a headache which most folks could easily avoid
> by using the (only tad bit slower for most installations) skiplist
> format which probably won't be changing much if at all between releases.
> I'm not saying BDB support should be removed as it will provide the
> fastest possible configuration for folks willing to deal with the
> potential hassles.  Anyway, just adding something like:
> ---
> # bypass BDB hell
> annotation_db: skiplist
> duplicate_db: skiplist
> mboxlist_db: skiplist
> ptscache_db: skiplist
> quota_db: skiplist
> seenstate_db: skiplist
> subscription_db: skiplist
> tlscache_db: skiplist
> ---
> 
> to imapd.conf will cover things for new installations.
> 
> At the very least, I would mention this as either part of a
> debconf message or in one of the Debian README files so that folks are
> aware of the potential dangers in using the BDB backend and a really
> simple way to avoid trouble by using only skiplist instead.
> 
> I was thankfully able to convert the necessary db4.2 files I had
> over to skiplist.  After removing /var/lib/cyrus/db(.backup[12])?/* and
> the skiplist conversion for everything else (.db, .seen and .sub files),
> Cyrus is stable again and I have yet to see any further problems.
> 
> -- System Information:
> Debian Release: testing/unstable
>   APT prefers testing
>   APT policy: (700, 'testing'), (600, 'unstable'), (500, 'stable'), (1, 
> 'experimental')
> Architecture: i386 (i686)
> Shell:  /bin/sh linked to /bin/bash
> Kernel: Linux 2.6.13.4
> Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
> 
> Versions of packages cyrus22-imapd depends on:
> ii  cyrus22-common2.2.12-1   Cyrus mail system (common files)
> ii  libc6 2.3.5-8GNU C Library: Shared libraries 
> an
> ii  libdb4.2  4.2.52-18  Berkeley v4.2 Database Libraries 
> [
> ii  libsasl2  2.1.19-1.7 Authentication abstraction 
> library
> ii  libssl0.9.8   0.9.8a-3   SSL shared libraries
> ii  libwrap0  7.6.dbs-8  Wietse Venema's TCP wrappers 
> libra
> 
> cyrus22-imapd recommends no packages.
> 
> -- no debconf information
> 
> 
> 
> ___
> Pkg-Cyrus-imapd-Debian-devel mailing list
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Bug#342660: cyrus22-imapd: suggest making skiplist the default database backend for new installs

2005-12-09 Thread Henrique de Moraes Holschuh
On Fri, 09 Dec 2005, Mark Nipper wrote:
> anything BDB.  There are seemingly known issues even using db4.3 and

db4.3 != db4.2... and there is *NO* *CHANCE* of we linking to BDB 4.3
anytime soon, if I can help it.

Skiplist is sensitive to corruption.  As in: if it happens, you can start
crying.  It *can* and *does* deal well with aborted transactions, that's not
what I am talking about.

bdb 4.2 is fairly resilient to corruption, most of the time a db4.2_recover
will do just that, with no data loss.  It is also faster than skiplist for
random lookups (mailboxes DB/TLS DB/duplicate delivery suppression DB),
*especially* when you have a huge ammount of processes doing it (which
happens to the mailbox db).

So, I really think we should keep using BDB 4.2 as a default for those
functions where upstream recommends doing so for performance reasons.

> although I upgraded all of my existing db3 files to db4.2 using
> db4.2_upgrade, I still ended up having cyrmaster crash on me due to
> critical database errors.

Cyrus needs to be stopped for that to work without causing corruption,
AFAIK.  I didn't attempt a db migration yet using Cyrus, but it is always
posible to do so using dumps.

> At the very least, I would mention this as either part of a
> debconf message or in one of the Debian README files so that folks are
> aware of the potential dangers in using the BDB backend and a really
> simple way to avoid trouble by using only skiplist instead.

No debconf obnoxious messages.  This is non-negotiable.  But discussing
about the good and bad of each database backend in the documentation is a
good idea.

-- 
  "One disk to rule them all, One disk to find them. One disk to bring
  them all and in the darkness grind them. In the Land of Redmond
  where the shadows lie." -- The Silicon Valley Tarot
  Henrique Holschuh


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Bug#342660: cyrus22-imapd: suggest making skiplist the default database backend for new installs

2005-12-09 Thread Mark Nipper
Package: cyrus22-imapd
Version: 2.2.12-1
Severity: wishlist
Tags: patch

After recent problems upgrading from the 2.2.12 packages
previously available from debian.speedblue.org which were using db3 to
the new official packages using db4.2, I would suggest making the
default backend for everything on a new installation skiplist over
anything BDB.  There are seemingly known issues even using db4.3 and
although I upgraded all of my existing db3 files to db4.2 using
db4.2_upgrade, I still ended up having cyrmaster crash on me due to
critical database errors.

This seems like a headache which most folks could easily avoid
by using the (only tad bit slower for most installations) skiplist
format which probably won't be changing much if at all between releases.
I'm not saying BDB support should be removed as it will provide the
fastest possible configuration for folks willing to deal with the
potential hassles.  Anyway, just adding something like:
---
# bypass BDB hell
annotation_db: skiplist
duplicate_db: skiplist
mboxlist_db: skiplist
ptscache_db: skiplist
quota_db: skiplist
seenstate_db: skiplist
subscription_db: skiplist
tlscache_db: skiplist
---

to imapd.conf will cover things for new installations.

At the very least, I would mention this as either part of a
debconf message or in one of the Debian README files so that folks are
aware of the potential dangers in using the BDB backend and a really
simple way to avoid trouble by using only skiplist instead.

I was thankfully able to convert the necessary db4.2 files I had
over to skiplist.  After removing /var/lib/cyrus/db(.backup[12])?/* and
the skiplist conversion for everything else (.db, .seen and .sub files),
Cyrus is stable again and I have yet to see any further problems.

-- System Information:
Debian Release: testing/unstable
  APT prefers testing
  APT policy: (700, 'testing'), (600, 'unstable'), (500, 'stable'), (1, 
'experimental')
Architecture: i386 (i686)
Shell:  /bin/sh linked to /bin/bash
Kernel: Linux 2.6.13.4
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)

Versions of packages cyrus22-imapd depends on:
ii  cyrus22-common2.2.12-1   Cyrus mail system (common files)
ii  libc6 2.3.5-8GNU C Library: Shared libraries an
ii  libdb4.2  4.2.52-18  Berkeley v4.2 Database Libraries [
ii  libsasl2  2.1.19-1.7 Authentication abstraction library
ii  libssl0.9.8   0.9.8a-3   SSL shared libraries
ii  libwrap0  7.6.dbs-8  Wietse Venema's TCP wrappers libra

cyrus22-imapd recommends no packages.

-- no debconf information


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