high-availability Cyrus (i.e. glusterfs)?

[Michael Menge]

Quoting Tomasz Chmielewski <mangoo at wpkg.org>:

> On 28.09.2010 10:56, Michael Menge wrote:
>
>> Cyrus depends on locks and mmap, so your fs must support them.
>> I had written a summery of the diskussions about Cyrus and HA in the
>> old wiki. But the wiki was replaced by the new wiki. I will have a look
>> if I have a copy.
>
> I would be grateful.
>
I didn't find the Wiki Text, but the thread that was the base of this
Wiki-Text

http://www.irbs.net/internet/info-cyrus/0611/0279.html

>
>> If you plan to run in active-passive mode, did you considre Cyrus
>> replication? You will need twice the disk space, but you remove a single
>> point of failure (glustefs)
>
> Glusterfs is there to avoid SPOF - as the filesystem sits on two
> servers. So assuming I won't do rm -rf /gluster-filesystem, it should be
> quite safe. And it too needs twice the disk space, since it's replicated
> with glusterfs on both servers.

So there is no differens in diskspace. If glustefs keeps two copies of
each file or if you have two Cyrus-Servers. But with Cyrus Replication
you don't have the problem with mmap and locking. It may help not to use
BDB for the databases. But i don't know how good skiplist is in 2.2.13.
Many skiplist bugs have been fixed in 2.3.x

>
>
> However, I'm of course open to better alternatives.
>
> I'm running Debian Lenny, which ships with Cyrus 2.2.13 - not sure if
> Cyrus replication is possible there? I'd like to stick with distro
> packages, but if a newer Cyrus version provides features which let you
> do HA without too much hackarounds, I'll consider upgrading.
>

Replication was introduced in 2.3.x. There are other features in 2.3.x
I don't want to live with out (e.g. delayed expunge). There was a
diskussion on the lists about that Debian wants to upgrade cyrus.
The main problem is the upgrade path (update of BDB Databases).




--------------------------------------------------------------------------------
M.Menge                                Tel.: (49) 7071/29-70316
Universität Tübingen                   Fax.: (49) 7071/29-5912
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