Maximum LUN Configuration and Considerations for HP-UX

ManualsBrandsHP ManualsSoftwareHP-UX 11i v1.6 Technical Computing (TCOE) LTU

Abstract.............................................................................................................................................. 2

Terms and Definitions........................................................................................................................... 2

Introduction......................................................................................................................................... 3

Supported LUN Maximums on HP-UX ..................................................................................................... 4

HP-UX 11i v1 Maximums .................................................................................................................. 5

HP-UX 11i v2 Maximums .................................................................................................................. 5

HP-UX 11i v3 Maximums .................................................................................................................. 5

Device Maximums ............................................................................................................................... 6

Considerations .................................................................................................................................... 6

Server Considerations....................................................................................................................... 6

Kernel Tunables ............................................................................................................................... 6

Volume Manager Considerations....................................................................................................... 6

File System Considerations................................................................................................................ 7

Scan/Startup/Shutdown Times .......................................................................................................... 7

Topology Considerations .................................................................................................................. 7

Roadmap / Futures .............................................................................................................................. 8

Additional Resources............................................................................................................................ 8

Summary of content (8 pages)

PAGE 1
Maximum LUN Configuration and Considerations for HP-UX Abstract.............................................................................................................................................. 2 Terms and Definitions ........................................................................................................................... 2 Introduction.........................................................................................................................................
PAGE 2
Abstract Mass storage requirements have increased dramatically over the last few years. High-end HP-UX customers now require many terabytes of storage and thousands of storage devices (LUNs) to be accessible from a single HP-UX server. This paper highlights the increases in the maximum number of LUNs supported with HP-UX servers and at component levels such as per-HBA (Host Bus Adapter).
PAGE 3
Introduction Over the years, there have been many advances in mass storage I/O interfaces and protocols, mass storage devices, and server technologies: • • • • • • Link speeds many times faster (4GB Fibre Channel and 10 Gigabit Ether) Device data transfer speeds over ten times faster (Atrium 960 @ 160MB/s) LUN capacities greater than 2TB Disk storage requiring a merge of network and mass storage functionality Greater number of logical units and storage capacity required per server Higher scalability and ap
PAGE 4
On the other hand, if a system has 2000 attached LUN devices with 2 paths to each device, all of which are accessed through a dynamic multi-pathing module, then the number of Active LUN paths would be 4000. This would be the case by default on HP-UX 11i v3 since native multi-pathing will load-balance across all available LUN paths. Supported LUN Maximums on HP-UX HP-UX supports maximum LUN configurations as defined in Table 1.
PAGE 5
• 1024 LUN devices, with 4 paths to each device, all accessed via dynamic-multi-pathing modules: ⇒ 4096 Active LUN paths, 4096 Open and Visible LUN paths • 512 LUN devices, with 16 paths to each device, 8 of which are accessed via dynamic-multipathing modules (the other 8 per LUN device not being configured for normal use): ⇒ 4096 Active LUN paths, 8192 Open and Visible LUN paths HP-UX 11i v1 Maximums The higher LUN maximums shown in the “11i v1 on or after December 2003” column of Table 1 are supported
PAGE 6
With the September 2007 release of HP-UX 11i v3, the maximum number of “Active” and “Open/Visible” LUN paths supported is 262144.
PAGE 7
Note: The total amount of disk space that a volume group can contain is set when the volume group is created, based on the user-specified extent size and maximum number of extents. To ease future expansion, carefully consider the options specified at volume group creation. File System Considerations Due to long recovery times, HP does not recommend using HFS file systems with large numbers of LUNs. HP recommends using the VxFS file system with large LUN levels.
PAGE 8
Roadmap/Futures To meet future customer needs, the maximum LUNs supported by HP-UX will continue to increase. The HP-UX development team is also working on significantly decreasing the overheads associated with managing, scanning, and displaying large numbers of LUNs to provide streamlined management of large storage attachments. Additional Resources White papers related to HP-UX 11i v3 mass storage Go to http://docs.hp.com/en/netsys.