Cache - the more the better. Obvious. However there are different ways
of use of DRAM as a cache.
Some vendors have cache mirrored. Others don't mirror READ cache.
Usually the same memory is used for other purposes, not only for caching
READs and WRITEs. So, "1TB of cache" is not simply comparable between
vendors.
Disk module. SSD or magnetic? Usually SSD nowadays. But which SSD? There
are many flavours and capacities.
Usually smaller modules gives better overall performance. And better
flexibility. And there are faster and slower modules.
Remote copy.
Do you want to perform PiT copy on secondary/slave?
Do you want asynchronous copy?
Do you want PPRC and FLASHCOPY command compatibility?
What QoS features of PiT and Remote Copy do you want?
etc.
--
Radoslaw Skorupka
Lodz, Poland
W dniu 04.09.2024 o 20:27, Peter pisze:
Thanks for the inputs
Currently we are metro mirrored.
So I believe I also need to look into their quality of support?
Cache and modules? - what exactly I need to be researching on this ?
On Wed, 4 Sept 2024, 19:40 Radoslaw Skorupka, <
[email protected]> wrote:
W dniu 04.09.2024 o 10:52, Peter pisze:
Hello,
I Must confess that I am not a Storage expert. In our organization we
are
working on procuring a new storage box solution. I have been asked to
study and give an opinion on which solution would be perfect for our
mainframe environment.
Could someone give me your advise based on your experience. When
selecting
a new storage solution what are the important points that needs to be
looked into the vendors proposal ?
Generally speaking a DASD box is not just a bunch of disks. It is DASD
space + performance + embedded software.
DASD space - obvious
performance - a little bit more complex. There is no single number, like
car velocity. Even cache size should be understood, because vendors have
different way of use of it. Two approaches: compare "guts" (cache, disk
modules, etc.) or compare benchmarks.
embedded software - remote copy, point in time copy, some "obvious"
things like SuperPAV, etc. Unless you have specific requirements all
vendors apply. However their offering differ and it could be important.
And features like Safeguarded copy.
...and zHyperlink. All vendors have FICON32 nowadays, and AFAIK all do
have zHyperlink.
HTH
--
Radoslaw Skorupka
Lodz, Poland
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