Re: NVMe's Namespace size

Not a new recommendation at all. Usually when a system is preloaded or built by IBM, they do not know your needs, therefore they usually just create a 400Gb unit and then let you configure the rest of the storage. That’s done in DST/SST with (V7R3 macros) or V7R4+ with the menu options. It’s likely the CSR (CE) was not IBM i trained (as opposed to AIX) so a large storage space was OK since AIX likes that type of storage.

If that nvme was set up as one unit (mirrored) that will affect performance in a big way, but is partially overcome by the speed of access to storage. It is possible to fix it but it will require some surgery to do it.

Adding the new units will go a long way to fixing that, however if the large storage units are left on the system, it will preferentially go to the biggest storage unit with I/O (long standing issue in storage management) so in the end, you may need to fix that before you get to the performance standard that makes you happy. The biggest impediment to getting that done will be if the load source is huge, changing that is the real problem and requires some real serious system knowledge to pull off.


Jim Oberholtzer
Agile Technology Architects

On Jan 31, 2024, at 2:23 PM, Gad Miron <gadmiron@xxxxxxxxx> wrote:

Thanks Stefan, Jim, Patrik

Having used the Multi-Name-Beast (AS400/iSeries/Series5...) for longer then
I care to remember
I know the golden rule "The more disk arms the better"
What I want to know is what performance gain to expect.
However,
having opened a case at IBM I was asked to supply a SYSSNAP (which I have)
for them to evaluate. (they referred me to Expert Labs team first but then
reconsidered)
Let's hope.

Thanks again guys.
Gad

P.S.
Since this is a fairly new machine (6 months) I wonder why the IBM CE that
installed it
did not configure those multitudes Namespaces right then.
Seems like a new recommendation for NVMes
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