Is there anything I can do to speed up the creation of the HP Smart Array logical drives?
Does creating too many drives at the same time affect the overall performance?
The most effective way to speed up array creation (all other things being equal, and assuming you're not trying to initialize so many arrays that you're saturating the controller's bandwidth) is to install faster disks.
Re: creating too many drives hurting performance - Definitely possible, but I'm not sure what the point of diminishing returns here would be (it's at whatever point the disk bandwidth is saturated, or the controller is "overworked" and letting drives sit idle for a few milliseconds between issuing commands -- perhaps an HP storage expert could be more specific...)
Remember that array initialization is normally a one-time event - If you can complete an array rebuild within a reasonable time and the overall performance of the system is acceptable when it goes into production it may not be such a terrible thing to have a slow process that only happens once in the life of a system...
I wouldn't be using a P411 for this, I'd be using a P812.
I have a LOT of MSA70's and although my usage is different from yours and the 411 supports that many logical disks doesn't mean it's the best kit for the job. I use the 812's simply because they handle so much more concurrent workload - whether that's creating multiple logical disks at once or, more importantly for me, handling thousands of concurrent requests I'd go with the 812 every time.
As for your questions? No there's nothing you can do to speed it up once it's got going and yes creating multiple simultaneously will be slower than doing them sequentially.
Maybe I'm off-base here, but I'm not sure which type of MSA unit this is. But if these arrays are to belong to a single server, would it make sense to create an array consisting of a large number of disks, then create smaller logical drives of the RAID-level and size required, leveraging the Smart Array's unique capability of mixing and matching RAID levels within a given array?
Edit - Also, do you have an option for RAID 1+0? Wouldn't the creation time be faster and the resulting arrays be more performant?
e.g. here's the output of a 6-disk array containing multiple logical drives.