Re: RAID controller #2757 & #2780

I am assuming your existing 0595 is full with 12 disks.  If it is not full
then you can add more to get to the 12 limit in the 0595.

If you are getting a new 0595 you will need a DASD controller.  IBM has
withdrawn the 2757 and replace with the 2780.

1. They are functionally the same with the 2757.  It does have 1gb
compressed read cache and ability to swap cache battery
without removing the card from the system.

2.  Yes you can but I cannot see a reason to swap the cards.

3.  Yes in a raided system you cannot just buy a 2780, you must also get
the cache backup[1].  The only way around is to
      have the configurator tell the system is mirrored.  Then you can get
the 2780 by itself.  You must have an even number of drives,
      so plan accordingly.

[1]  IBM made this requirement because of the large write cache on the DASD
card.


Read about the 2757 and 2780 here...
http://www.redbooks.ibm.com/Redbooks.nsf/RedbookAbstracts/sg242155.html?Open

_____________________________
Bryan Dietz
Aktion Associates

midrange-l-bounces@xxxxxxxxxxxx wrote on 11/21/2005 11:26:14 PM:

>  Hello All:
>
> Currently, I had a i520 with #0959 populated with 15K 35G disk using
#2757.
> We need to add in more disks in #0595.
>
> 1. Is there is significant difference between #2757 & #2780, especially
in
> terms of performance in a RAID environment?
>
> 2. If I'm currently using #2757 RAID controller card with RAID protection
> and have existing data in it, can I upgrade/change it to a #2780 without
> having to perform a reload, or lost of data?
>
> 3. The eConfig will alway force a #5580 instead of a #2780 in a RAID
> configuration, can I just use #2780 alone in a RAID environment without
the
> auxiliary write cache?
>
> Digitally Yours,
> IGS Ang