Re: CACHE BATT EXP 90 DAYS???

[Larry Bolhuis <lbolhuis@xxxxxxxxxx>]

If your data is properly mirrored then a failure does NOT stop the 
system. A System i protected with RAID, no matter what it's value, does 
in fact stop if a controller fails. I would be read the EMC SAN 
documentation carefully because I suspect they maintain redundant paths 
to your DATA not necessarily multiple paths to the same physical disk 
unit. While the net effect of this to systems using such a SAN is no 
different the complexity and cost of such a setup is going to be higher 
than Mirroring on i5/OS.  Plus it's another machine to maintain, from 
another vendor, and performance of SAN based disk solutions for System i 
must be carefully monitored or you can create I/O bottlenecks very very 
easily.

And of course that is why the 'assume' word is a bad one. You can build 
a system as small as a model 550 with redundant paths to all data. You 
can build a model 595 with no disk protection whatsoever. This is why 
the more important your data the more skilled you want the person who 
designs your system, no matter how large your system is, or isn't.

 - Larry

Lukas Beeler wrote:
> That's why I said "assume".
>
> A colleague of mine works for EMC, and their enterprise SAN systems have
> redundant access paths to all disks, and also redundant controllers. I
> have assumed that a 595 is similar to an enterprise SAN when it comes to
> storage architecture.
>
> Or would the failure of a single RAID controller bring a system worth
> multiple million dollars to its knees?
>