User Manual

Rev 1.8.2
Mellanox Technologies
15
For example, to set the maximum number of SRP targets per SCSI host to four, run:
6. To find out all SRP's parameters, run:
Default values are usually optimum per performance however, if you need to manually set the system
to achieve better performance, tune the following parameters:
• srp_sg_tablesize - Maximum number of scatter lists supported per I/O.
• srp_cmd_per_num - Maximum number of commands can queue per lun.
• srp_can_queue - Maximum number of commands can queue per vmhba.
7. To check performance:
a. Windows VM - Assign luns to VM as raw or RDM devices Run iometer or xdd
b. Linux VM - Assign luns to VM
c. In case of multiple VMs, generate I/Os for performance testing
4.1.1.2 Multiple Storage Adapter
SRP has the ability to expose multiple storage adapters (also known as vmhbas) over a single
InfiniBand port. By default, one storage adapter is configured for each physical InfiniBand port.
This setting is determined by a module parameter (called max_vmhbas), which is passed to the
SRP module.
1. To change it, log into the service console and run:
As a result, <n> storage adapters (vmhbas) will be registered by the SRP module on your machine.
2. To list all LUNs available on your machine, run:
4.2 IP over InfiniBand
4.2.1 IPoIB Overview
The IP over IB (IPoIB) driver is a network interface implementation over InfiniBand. IPoIB
encapsulates Datagram transport service. The IPoIB driver, ib_ipoib, exploits the following Con
-
nect®X/ConnectX®-2/ConnectX®-3 capabilities:
• Uses any CX IB ports (one or two)
• Inserts IP/UDP/TCP checksum on outgoing packets
• Calculates checksum on received packets
• Support net device TSO through CX LSO capability to defragment large datagrams to
MTU quantas.
• Unreliable Datagram
IPoIB also supports the following software based enhancements:
• Large Receive Offload
• Ethtool support
cos# esxcfg-module ib_srp -s 'max_srp_targets=4'
cos# vmkload_mod -s ib_srp
cos# esxcfg-module ib_srp -s 'max_vmhbas=n'
cos# reboot
cos# esxcfg-mpath -l