[openib-general] iSER & FC-SAN performance

[Yaron Haviv]

> -----Original Message-----
> From: openib-general-bounces at openib.org [mailto:openib-general-
> bounces at openib.org] On Behalf Of Mohit Katiyar, Noida
> Sent: Friday, March 10, 2006 11:36 AM
> To: openib-general at openib.org
> Subject: [openib-general] iSER & FC-SAN performance
> 
> Hi All,
> Are there any performance related data of iSER is available or some
test
> results that were performed on iSER?
> Are there any kinds of operational issues in the performance of iSER
in
> an general FC-SAN environment? I am also looking for some reference
> material of operations of iSER on FC Gateway environment?
> Thanks in advance
> 
> Mohit Katiyar

Mohit,

Your question should be broken to two, one is the iSER performance and
the other is an IB to FC gateway performance, and both are very
implementation dependent 

iSER initiator uses zero copy and can map a large SCSI command to a
single send+rdma transaction, this allows for very high-bandwidths and
low CPU% as the message size grow, the performance we saw is >900MB/s
per initiator 
this was tested with a 4X SDR link (1000 MB/s capable), with DDR it may
achieve more.

As for IB-FC gateway performance, it depends on the HW architecture of
the gateway rather than if its iSER or SRP, e.g. what's the memory BW
capacity of the gateway, pci-x vs. pci-express, CPU capacity, and FC
ports  
When targeting larger messages the mem/bus bandwidth become much more
critical than the cpu capacities.

As an example an iSER-FCP gateway would typically implement a store &
forward design (other designs can be achieved as well), the SCSI command
would be intercepted, data would be fetched to memory (using RDMA), and
a SCSI transaction would be performed on the FC side (were the FC
adapter will fetch the data using DMA), in a good gateway implementation
multiple I/Os can flow in parallel (asynchronous), this can sustain the
900MB/s in some architectures, in addition multiple gateways can be
aggregated to scale bandwidth of many GB/s of data, while still enjoying
the single name space and even emulate a single session leveraging on
iSCSI mechanisms. 

The different options for iSER to FC gateways would include:
1. Voltaire FCR product
2. FalconStore NSS product on a PC platform (with IB & FC adapters) 

You can address the different vendors to get more details on their
products & performance, I can point you to the right contacts offline 

Yaron


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