New DL380e-G8: Use one single p822 Smart Array controller vs p420 plus p421?

[Neal Howard]

I'm getting ready to buy a new DL380e G8 storage version server with the 25 disk array, and will also need to connect an MSL2024 dual LTO6 tape library. I intend to fill the disk array full of 900GB SAS disks, so I'll need a Smart Array controller to host those. I also need an SAS controller to connect the external tape machine as well.

The p822 Smart Array card has both internal and external SAS connections, but I'm worried about the possibility of I/O bottleneck when pushing all that data from nearly ~20TB of internal disk storage plus the tape machine's traffic all simultaneously thru the one single card plus its PCIe slot bus connection while tape backups are running.

Wouldn't I be better off with a p420 controller card to handle the internal disk array and a p421 controller card to connect to the external tape library, so that when backups are running, the I/O load will be distributed thru two separate controller cards and two separate PCIe bus connections?

This server will also be hosting my network backup software as well as being the main user's file share server for a couple hundred users, so there will be times during every day where it will also be ruinning backups to the tape library for about 10 other servers and databases over the network.

[Neal Howard]

Bump. 

Nobody got any firsthand info on this?

I found another thread in the Storage/Tape/Tape Libraries and Drives discussion section where a fellow with a Proliant G6 machine and a P800 Smart Array controller is having show-stopping timeouts and connection dropout problems with the combination of a disk array and a brand new MSL2024 dual LTO6 library both attached to a single P800 controller card. HP has been working with him for over a week and unable to solve the problems, so that does not bode well for the P8xx card when you're mixing disk and tape connections at the same time thru the same card.

[Dennis Handly]

>I found another thread in the Storage > Tape

I assume this topic?

http://h30499.www3.hp.com/t5/Tape-Libraries-and-Drives/Issues-with-P800-and-Brand-new-HP-MSL2024-Ultrium-6520-LTO-6-X-1/m-p/5961613

[Neal Howard]

Yes, that's the thread.

I have since gotten to speak with an SA at HP and he also advised to host the MSL2024 dual LTO tape library on its own controller, separate from any disk arrays. In order to maximize future expandability of my new server, I'll now be buying it with a P421 card dedicated for the tape machine, and actually decided to go ahead and get the P822 card to host the internal 25-disk array plus the possibility to add on a future MSA P2000 external disk array chassis since the P8xx cards are known to work well with multiple disk arrays connected.