Ensure the PCI slots do not share internal BUS bandwidth. You may end up with issues there- I moved to dual port PCIe cards for the internal bandwidth to run many LTO3 drives. Is the server really only PCI, or are they PCI-X slots?
There is no issues running LTO2 and LTO3 on the same HBA. I have looked into the fabric throughput to actually see the speeds- they can be very high- near the theoretical maximums if you are using format=drives or UTRIUM3/2C. Any type of oversubscription/commitment can cause severe impact on streaming performance. _____________________________ Ian Smith SAN/TSM Specialist Hitachi Data Systems Certified Professional IBM Tivoli Storage Manager Certified Consultant -----Original Message----- From: ADSM: Dist Stor Manager [mailto:[EMAIL PROTECTED] On Behalf Of Robin Sharpe Sent: 29 August 2006 16:51 To: ADSM-L@VM.MARIST.EDU Subject: [ADSM-L] LTO-2 and LTO-3 switch grouping Hi All, We have the good fortune to be adding four LTO-3 drives to our STK L700 library. It currently has 14 LTO-2 drives, attached to two Brocade 3800 (2Gpbs, 16-port) switches. All drives are IBM FC. I'm trying to figure out the best approach to zone these drives. We currently use port zoning on these switches, but as part of this upgrade, we will enable the WWN feature on the L700, and migrate the switches to WWN zoning. Here are my thoughts... Current config: (4) HBAs on the TSM server for tapes On switch1, hba1 has (3) LTO-2 drives hba2 has (4) LTO-2 On switch2, hba3 has (3) LTO-2 plus (3) DLT8K (the DLT's are going away with this upgrade) hba4 has (4) LTO-2 The DLT's are never used, so they have no real impact. I know the hba's with (4) LTO-2 are over-committed, and although I have no direct evidence of a problem, my gut feeling is that it is a bottleneck at times. I have a few FC cards that I can add. There are two open PCI slots on the TSM server... with some more reconfiguration, I can free up two more. This is an HP rp7410 server, and all PCI slots are 66Mhz x 64 bit capable, with throughput of 530MBps.... so, I can put FC adapters anywhere with no throughput concerns. What I'm considering: - IF I can add four more HBAs (best case - no over-commitment), On each switch, hba1 with (1) LTO-3 and (1) LTO-2 hba2 with (1) LTO-3 and (1) LTO-2 hba3 with (3) LTO-2 hba4 with (2) LTO-2 -If I can only add two HBAs (less reconfiguration), On each switch, hba1 with (1) LTO-3 and (1) LTO-2 hba2 with (1) LTO-3 and (2) LTO-2 (44 MBps over-commitment) hba3 with (4) LTO-2 (24 MBps over-commitment) My "over-commitment" calculations are based on 2048 Mbps / 8 bits per byte = 256 MBps throughput per switch port. I'm wondering if there are any issues with zoning LTO-2 and LTO-3 to the same HBA... will either one monopolize the port, or will play nice together? Any comments are greatly appreciated! Regards, Robin Sharpe Berlex Labs 973-487-5686 _____________________________________________________________ This email (including any attachments to it) is confidential, legally privileged, subject to copyright and is sent for the personal attention of the intended recipient only. If you have received this email in error, please advise us immediately and delete it. You are notified that disclosing, copying, distributing or taking any action in reliance on the contents of this information is strictly prohibited. Although we have taken reasonable precautions to ensure no viruses are present in this email, we cannot accept responsibility for any loss or damage arising from the viruses in this email or attachments. We exclude any liability for the content of this email, or for the consequences of any actions taken on the basis of the information provided in this email or its attachments, unless that information is subsequently confirmed in writing. If this email contains an offer, that should be considered as an invitation to treat. _____________________________________________________________