high-availability again

[zorg]

Hi,

Ok the solution with SAN seems good but did someone try this with the 
linx virtual server (lvs) ???

Dave McMurtrie a écrit :

> zorg wrote:
>
>> Hi
>> I'v seen in the list lot of discussion about availabity but none of 
>> them seem to give a complete answers
>>
>> I have been asked to build an high-availability for 5000 users
>>
>> I was wondering what is actually the best solution
>>
>> Using murder Idon' t really understand if it can help me. it's 
>> purpose is for load balancing.
>
>
> Murder, by itself does not give you high availability.  It does give 
> you scalability.
>
>> but some people on this list seem to use it for availabily like this
>> - Server A
>>  - active accounts 1-100
>>  - replicate accounts 101-200 from Server B
>> - Server B
>>  - active accounts 101-200
>> - replicate accounts 1-100 from Server A
>> If B goes down, A takes over the accounts it had
>> replicated from B.
>>
>> if someone can explain the detail of this conf ?
>> - the tool use to replicate ?
>> - what configuration of the MUPDATE make it to switch the user to 
>> server A from B ??
>
>
> I'm not familiar with this.
>
>> Replication with rsync
>> see to slow the 5000  user
>
>
> It'd be tough to do this real-time.  We used to have a setup where 
> we'd rsync to a standby server each night.  The plan was to use it as 
> a warm-standy in case the primary server would happen to fail. 
> Fortunately that never happened.
>
>> Cluster with block device
>> but if you have a heavily corrupted filesystem. yau are stuck. and 
>> recovery can be long
>
>
> I'm not sure exactly what you mean here, but I think it's safe to say 
> that any time you have a corrupted filesystem it's bad whether it's a 
> clustered filesystem or not.
>
>
>> Using a SAN : Connect your two servers to a SAN, and store all of
>> Cyrus' data on one LUN, which both servers have access to.  Then, set
>> your cluster software to automatically mount the file system before
>> starting Cyrus.
>
>
> We're doing this.  We have a 4-node Veritas cluster with all imap data 
> residing on a SAN.  Overall it's working quite well.  We had to make 
> some very minor cyrus code changes so it'd get along well with 
> Veritas' cluster filesystem.  This setup gives us high availability 
> and scalability.
>
>> but if you have a heavily corrupted filesystem. yau are stuck. and 
>> recovery can be long
>
>
> Again, yes.  It would be bad if we had a corrupt filesystem.
>
> Thanks,
>
> Dave
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