Multiple paths to DMX

You can map metas (and generally speaking, any volume) on every port if you want. There are limits (number of devices mapped on a processor, number of luns mapped on a port) but generally speaking you can -if you want- map all the volumes on all the ports.



I don't see too many alternatives .. You need to map the volume on the FAs, zone the host (the HBAs) with the FAs, mask the volumes to the HBAs and discover the devices from the host point of view.



I think that steps 1 and 2 are not mutually exclusive. You can choose to either increase the connectivity from the host perspective (add more HBA to an already existing host) or expand the connectivity from the storage perspective (map the volume to additional FA) .. Or you can simply choose to apply BOTH of them

If you add more HBA or add more FA, you have however to zone the new paths and mask the devices you want to see.

Increasing host connectivity is usually needed only if you find that your HBA are too busy. Usually you have to increase storage connectivity (add more FA) since this gives more "queues" where to queue your IO operations. But it's a very complex chapter so please don't take my few words as a suggestion

As I usually say when I talk about performances .. IT DEPENDS !!

Message was edited by:
Stefano Del Corno

Stefano,

You are doing wonderful work in this forum. Thank you.

I got the pointers what I wanted and will move forward.

Kaizen

Kaizen plese don't tell my manager I spend that much time on the forums
He may fire me

Cheers !!

-s-

PS it's a pleasure for me to share the things I've learned while working for EMC.

hahahah ..i have same concerns, i am sure when my manager gets monthly web usage reports he sees forums_emc_com at the very top.

Unfortunatly my manager never receive similar reports .. Since I'm always at customer site

Kaizen10 if you have more questions or doubts, please update this thread .. We'll be glad to help you further .. If you ask

Talking about multiple paths to a DMX made me think about my speed record of copying data between 2 DMXs: I mapped 40 single symdevs and metas to as much as 14 FAs and copied 2TB withing the hour to the other DMX.....

Top speed 835MBps, average speed about 515MBps.

14FA ?? You have a lot of unused stuff in your boxes !! ..

Can you send some FA over the Alps ?? We always need some spare FA ...

Cheers !!

Who said anything about unused ? All the mentioned ports used to be in use by hosts (through switches of course).
It all happened in a Open Replicator migration from an old DMX2 to a new DMX3.
The DMX2 was nearly empty and only 3 servers were still attached. 2 Windows and 1 Sun. The Sun still had 40 lun's and the 2 Windows machines shared the same FAs. So all the other ports were already emptied and we had 14 ports (2 times 7) attached to the SAN. Only 14... that's not much ! Only FAx0 ports, not a single FAx1 port !

The DMX2 is already gone EMC took it back in october 2006. I think it's now a fish tank in Cork or something....

Ok so please migrate the three hosts on another storage and ship the whole DMX2 to me

You guys are so cool. I would like to read all your suggestions and one day i will become an expert.

I'm not changing your post simply becouse it's Easter

And if you want to become like me you need also

1) a ton (or two) of madness
2) an EMC badge
3) a big car (but it's a whole different story)

please pra2rgh ..don't become like Stefano ..we can barely stand him as it is