Re: Assure MIMIX

[DrFranken <midrange@xxxxxxxxxxxx>]

> We're doing mostly replication. One reason: depending on the crash,
> you don't know the state of the SAN
> (if you do full mirror including OS parts).

I Do not like the 'Full OS Mirror' option. I don't. Not even a little. 
Don't like it. Not a fan. You might wonder why.

First you lose many of the options that you have with other choices. You 
have no ability to use the backup site for anything. You can't do PTFs 
on one side while you run on the other side. You can't do backups on one 
while you run on the other. You can't do upgrades on one while you run 
on the other. Testing on the backup side requires a full stop of 
replication and likely a long time to get back in sync.

You guarantee an abnormal IPL absolutely. It may or may not come up 
correctly or quickly. It might not come up at all. It also adds 
significantly to replication traffic as all temp writes etc are 
replicated needlessly.

In summary I don't like it. Yes I have done it and in our tests we found 
issue after issue. Replicating iASP only is far better though still not 
perfect.


        - Larry "DrFranken" Bolhuis

www.Frankeni.com
www.iDevCloud.com - Personal Development IBM i timeshare service.
www.iInTheCloud.com - Commercial IBM i Cloud Hosting.

On 1/10/2020 10:21 AM, Holger Scherer wrote:
> This is always some kind of religious question:
> - do SAN mirror with two boxes, or
> - do replication with MIMIX (or other software. Here in germany BUS4i is the star replacing Mimix)
>
> We're doing mostly replication. One reason: depending on the crash, you don't know the state of the SAN
> (if you do full mirror including OS parts).
> We had one customer whose production system crashed (running about 180TB database).
> The switchover to the backup box with mirrored SAN was fast, but the IPL with
> checking the database, LF etc needed some 12 hours on a not so small box ;-)
>
> -h
>
>
> > Am 10.01.2020 um 15:56 schrieb DrFranken <midrange@xxxxxxxxxxxx>:
> >    
> > Wanna know the best part? The SANs continue replication while you do the PTFs and / or OS UPgrade!!! So you're not even behind when you're done.
> > Try THAT with MIMIX and friends!
>