What was announced?
On Monday May 11, 2009, QLogic announced the iSR6250, an enterprise-class router that addresses limitations in virtualized ESX environments and bridges between 8Gb FC and 1Gb/10Gb iSCSI networks. In conjunction with EMC, QLogic announced the following capabilities:
- 8Gb FC, 1Gb iSCSI, 10Gb iSCSI,
- Supports for 1024 iSCSI Hosts using initiator virtualization technology,
- Dual-blade configuration that can be expanded to 10GbE FCIP - SAN Over WAN.
Why does this announcement matter?
To be cost effective, VMware needs a large number of virtual machines for each real machine and a large amount of data storage (large number of LUNs) to manage. This is especially true in a high availability environment. Thus the rapid uptake of VMware creates a proliferation of small virtual machines. The management of application data behind these VMs is tedious and error-prone in general and especially when the number of data LUNs becomes so large (greater than 256) that the hypervisor has to start virtualizing the LUNs. This adds another layer of IT management complexity. The hypervisor, while simplifying many IT tasks such as provisioning, becomes a bottleneck. For example, to move a virtual machine, some of the storage resources are controlled in the hypervisor and need to be managed as a separate task, which is time-consuming and error prone.
Ssing an iSCSI iniator in each virtual machine avoids the VM data-management bottleneck. By using an iSCSI router, iSCSI initiators in the VM’s now can link directly to the existing FC backend infrastructure. When a VM is moved, the entire storage infrastructure moves with it, eliminating a cumbersome migration problem.
What does this mean to IT?
The net of this technology for CLARiiON customers is it should improve performance, lower management complexity/costs and reduce risk while leveraging existing CLARiiON FC infrastructure. EMC users can now extend beyond VMware’s 256 physical LUN limit and not disrupt existing management and security around software such as Mirrorview, SANCopy and SRDF. Specifically, when users hit VMware’s 256 LUN limit, the hypervisor takes over and virtualizes the LUNs. As such, security, SAN management and storage management procedures associated with these software components are handed over to the hypervisor and additional management functions need to be added to manage backend data LUNs.
Using QLogic’s iSR6250 as 10GbE connectivity for CX arrays,, users can virtualize 1024 virtual paths to the storage system. The iSCSI software initiator is embedded into each guest OS. This allows the guest OS to appear as a host down to the array without consuming valuable host connections on the array controller, easing growth and expansion within a VMware environment.
The QLogic technology also supports 10GbE, which is in line with the future direction of data center infrastructure.
What are the use cases for this device?
There are several applications EMC CLARiiON customers specifically and other users in general should consider with this product, including:
- VM deployments (as discussed above)
- Bandwidth aggregation (i.e. fan in) – which allows a large number of servers to be able to access each array and minimizes the ports and bandwidth required to achieve this.
- Branch office consolidation/data management - by connecting remote NAS heads over a WAN to the array, the storage can be moved to a central data center with significant improvement in utilization and storage management effectiveness.
- Simplification of test and development systems - the ease of set-up of the storage environment means that test systems can be set up and torn down very easily against copies of any production data and the cost of additional Fibre Channel can be avoided by bridging iSCSI coming from the test and dev systems onto a production FC environment.
- The ability to migrate systems from one server to another without manual intervention in the hypervisor means that reconfiguration of Cloud systems can be automated, an important step for being able to deliver reliability and low cost of management. Additionally, by supporting 1024 initiators on thin clients, all Cloud storage resources can be centrally located and secured.
What caveats should uses consider?
At a street price of under $40,000 this technology is applicable for sites with high growth and scalability requirements and solves a problem at a certain size—it’s not for everyone. Users should be aware that there is work to do to re-configure LUNs to exploit the QLogic router. While this is less work than re-configuring LUNs on a case-by-case basis. In addition, problem determination and fix procedures will need to be updated.
Even below the 256 LUN level users may find value because of the ability to maintain a 1:1 correspondence with VMs and data LUNs, lowering the cost of connection. Overall, the product should mean less work overall for sites with these characteristics:
- Sites with large numbers of servers, virtual servers and storage volumes that need to be moved or reconfigured on an ongoing basis, especially sites using high-availability storage software.
- Mid-range and large CLARiiON sites that have an investment in a fibre channel infrastructure that is working well.
- Sites that want to centralize the storage and management of remote NAS files systems without network performance overhead.
Action Item: Technologies like QLogic’s iSR6250 10GbE iSCSI router allow organizations to pursue virtualization strategies aggressively with minimal change in FC storage hardware infrastructure. To IT management and EMC CLARiiON customers this technology allows better leverage on existing FC assets in VMware environments, thereby minimizing performance, data management, and quality challenges often facing customers. Users should assess the impact of this technology against current and project VM scale to determine the payback points.