User Manual

Driver Features
Rev 1.4.1-
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cos# esxcfg-module ib_srp -s <param=value>
5. To apply your changes, reboot the machine:
cos# reboot
For example, to set the maximum number of SRP targets per SCSI host to four, run:
cos# esxcfg-module ib_srp -s 'max_srp_targets=4'
6. To find out all SRP's parameters, run:
cos# vmkload_mod -s ib_srp
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
3.1.1.2 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:
cos# esxcfg-module ib_srp -s 'max_vmhbas=n'
cos# reboot
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:
cos# esxcfg-mpath -l
3.2 IP over InfiniBand
3.2.1 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-
nectX/ConnectX-2 capabilities:
y Uses any CX IB ports (one or two)
y Inserts IP/UDP/TCP checksum on outgoing packets
y Calculates checksum on received packets
y Support net device TSO through CX LSO capability to defragment large datagrams to
MTU quantas.
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