How to connect 2 SAS Expanders

[pablocool]

Hi I have MegaRAID LSI 9265-8i card and two SAS Expanders IBM (Lenovo) 03X3834 and 19 3TB disks.
Question is how to properly connect two SAS Expanders to this MegaRAID card?
If I just connect one cable from MegaRAID to first SAS Expander and second cable to second SAS Expander every time I boot system I see such message:

All of the disks from your previous configuration are gone. If this is an unexpected message, then please power off your system and check your cables to ensure all disks are present. Press any key to continue, or 'C' to load the configuration utility.

I discovered I need to immediately reset system and now magically all disks and virtual drive are detected. I thought it may be some disk failing and not being able to spin up. But then I discovered that if I connect all disks over one SAS Expander (no matter which of those two, so both are fine) then issue is gone. So what may be the problem with using two sas expanders simultaneously?
Do I need to connect them to MegaRAID card in some special way?
Maybe I should connect them cascade or some redundant way?

 

[sethk]

Some dual or quad connector SAS DAS systems have a delay on the drives on the 2nd channel to prevent the enumeration of all the drives at once (e.g. Supermicro enclosures with SAS expanders). Not sure if that's part of the expander or the power on firmware.

 

[pablocool]

Maybe there is limitation that disks within same virtual drive cannot be under two SAS Expanders. However I havent found such in manuals.