13
SNIA
the possibility of packet loss – in other words a lossy been supplemented by a significant uptake of iSCSI
environment. TCP/IP mitigates this by providing guar- storage in support of virtual server environments. The
anteed delivery mechanisms for upper level protocols. pre-requisite, of course, was robust iSCSI support in vir-
SNIA
The result is some network latency, which in turn can be tual server software, including enterprise-level security
mitigated by network simplification (mininal router and integration with virtual server storage administra-
IP
hops, private subnets, etc) and quality of service set- tion interfaces. These capabilities have all emerged,
FOR
tings. The DCB enhancements can provide further laten- making iSCSI a viable and increasingly popular choice.
cy mitigation benefits to TCP/IP-based traffic. Most of the tens of thousands of iSCSI installations
UM
worldwide use 1 Gigabit Ethernet, on-board Ethernet
To understand the implications of FCoE for iSCSI, you ports and iSCSI software initiators. Workloads requiring
need to understand who buys iSCSI, for what environ- more than 1 Gigabit of bandwidth successfully use link
ments, and why. aggregation, or in particularly bandwidth-hungry consol-
idation environments 10 Gigabit Ethernet. Performance
Customer Perspective - Who buys iSCSI, is rarely an issue. Latency is also not an issue for the
and Why vast majority of business applications. For intensive
iSCSI deployments to date have typically been in tier 2 application workloads on heavily loaded CPUs, cus-
and tier 3 data centers in large organizations; in the tomers supplement the host with some kind of TCP/IP
core data center of small/medium enterprises; and in offload solution (though this is still fairly rare due to
remote offices. In other words, iSCSI is usually chosen the continued chip-level TCP/IP overhead reduction
for environments that Fibre Channel has had difficulty we’ve seen in Ethernet chip sets over the past 5 years).
penetrating due to cost, complexity, functionality and Consequently, customers who have implemented iSCSI
support issues. solutions are typically very satisfied. This is born out in
recent analyst reports from Gartner Group, Enterprise
The application sweet spot has been storage consolida- Strategy Group and The InfoPro where IT Directors
tion for business-critical Windows environments. Its reported high levels of customer satisfaction and inten-
popularity has been driven not only by the fact that tion to expand their iSCSI footprint.
iSCSI provides robust affordable SAN storage which is
particularly well-matched to environments running on The availability of FCoE (which, remember, is being
x86-based servers, but also by the fact that even entry- specifically designed to maintain backward compatibili-
level iSCSI disk arrays usually include sophisticated ty with existing Fibre Channel endpoint infrastructure –
data-management capabilities such as point-in-time that means World Wide Names, Fibre Channel fabric
copy, remote copy, LUN cloning and asynchronous mir- management, “converged” host bus adapters, and Fibre
roring. These features enable IT organizations to signif- Channel support matrix complexities) seems very
icantly improve provisioning, backup and recovery, unlikely to replace or displace continued iSCSI growth
while reducing infrastructure and administrative costs. in these sweet spot environments.
Besides product features and capabilities, an important
issue is that your current server and application admin- FCoE Deployment Scenarios
istrators typically have no problems configuring and All of this leaves the question of where will FCoE be
maintaining an iSCSI-based SAN. They all know how to deployed, and why. The “why” part of the question is
configure TCP/IP, and security and array management is fairly simple – the fundamental decision criterion for
quite simple. FCoE is a desire to move to a single network fabric in
the data center for storage and data communications.
Over the past 18 months, the Windows sweet spot has Let’s look at the “where”.
WWW.SNSEUROPE.COM FEB 09
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