Cyrus crashed on redundant platform - need better availability?

[Jure Pečar]

On Fri, 10 Sep 2004 13:24:42 +0200
Paul Dekkers <Paul.Dekkers at surfnet.nl> wrote:

> Although many on the list claim that this (having 2 boxes with 1 
> disk-array) is a nice way for redundancy I'm in doubt now if this is 
> true. It still takes 30 mins before everything is back again! It seems 
> to me that if there was a "live" version of cyrus available with a 
> synchronised mail-spool, that there was no outage noticeable for users 
> (except in losing a connection maybe). Am I right?

Having 2 boxes with one disk array leaves you wit a single point of failure
that you wouldn't think of immediately: filesystem. I learned that the hard
way. 
I'm planning to 'redesign' our storage: instead of one big volume that fscks
for hours, i'm going to split in in many mirrors and use them as cyrus
partitions. This way they could all fsck in parrallel. I'm going to lose the
'single instance store' capability, but thats a tradeoff that i'm willing to
take.

It happened to me at least once that the machine that crashed corrupted the
filesystem in a way that the machine that took over also crashed within
hours...
 
> Maybe it's time to continue on the "High availability ... 
> again"-discussion we had a while ago. If the cyrus developers are able 
> to implement this with some funding there are still some questions left 
> for me: how much time would it take before a "stable" solution is ready? 
> How many funding is expected? I still have to talk to management about 
> this, but I would really support this development and I'm certainly 
> willing to convince some managers.

The only high availability i see here is the google way. Cyrus is offering
you that with the 'murder' component.


BTW, you're mentioning FreeBSD ... doesn't it have some sort of background
fsck while the filesystem is moutned rw? 


-- 

Jure Pečar
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