Microsoft iSCSI initiator
Microsoft iSCSI initiator. New rules to the old game of storage
Basic connectivity
Microsoft iSCSI Initiator allows connecting a host computer (Windows-based, and Windows 7 or Windows Server 2008 R2 are recommended now) to an external iSCSI-based storage. It is extremely useful to deploy affordable and easy manageable SANs without additional hardware, using only your existing IP network infrastructure.Microsoft iSCSI initiator for Windows was released to public first in year of 2006 and it had immediately called attention to itself. No other component had boosted iSCSI SAN adoption in the way it did nearly half of the decade ago. Client-side IP SAN support from OS vendor directly made third-party initiators useless. Potential war of vendors stopped without even being started. In spite of suggestions that Microsoft could have better integration with hardware iSCSI offload engines, support RDMA, take care of iSCSI specification in a more flexible way and have smarter designed MPIO stack, without doubt, they deployed the whole solution good enough. With modern multi-core and multi-gigahertz CPUs dedicated hardware offload has less and less impact on resulting performance, RDMA is a good technology but it did not turn much heads. ERL2 (Error Recovery Level 2) and too many iSCSI sessions are not popular among iSCSI target vendors as everybody prefer to use MPIO to provide redundancy and increase performance. Finally, iSCSI target-side manufacturers tend to provide their own MPIO extension modules in a way of plug-ins so no real problem exists these days. Microsoft had created another high standard: Microsoft iSCSI initiator. It’s very first piece of the software any iSCSI target vendors start testing their server-side iSCSI stack against of. No compatibility and stable work with Microsoft iSCSI initiator – no ticket to ride. VMware ESX and ESXi branched out original Cisco iSCSI initiator, Citrix Xen built-in iSCSI initiator, freeware implementations for Linux Open-iSCSI and its clones – they always follow, Microsoft iSCSI initiator makes a start for any collaboration.
Hypervisors
With Microsoft own hypervisor called Hyper-V Microsoft, iSCSI initiator got its new life stage. Hyper-V might be not that powerful as VMware ESX (yet) but it has its own set of benefits. First of all it’s free and does much better job compared to also free VMware’s ESXi alternative so as a result we can see more and more widespread Hyper-V adoption. Second, Hyper-V could run on top of Windows server, so people who are familiar with Windows don’t need to step on the UNIX side of the power. Keeping all eggs in the same basket does not sound like a good idea, so having one hypervisor node with all virtual machines kept locally on DAS hard disk array is far from the best practice – that’s why people need multiple hypervisor nodes and shared clustered volume. Fibre Channel is known to carry shared storage for years, it works just fine and provides top notch performance but it’s expensive and hard to manage and maintain leaving iSCSI as the natural choice for hypervisor-based infrastructure, and Microsoft iSCSI initiator, being now part of Hyper-V node, plays key role in this situation.Disaster Recovery
We can probably name third part of this sequel - it’s backup to cloud. Having all data residing on redundant volumes and scattered among different storage nodes is not enough, having disaster recovery plan is a must. So we definitely need some sort of the transport acting as a backbone for local site to remote site replication. IP SAN technology, iSCSI is absolutely native pick here as it uses IP transport thus it’s easily routable, it has no working range limitations like Fibre Channel has and there are many third-party iSCSI target components distributed as a VSA (Virtual Storage Appliance), so it provides “upload and run” strategy without need to configure any extra dedicated hardware directly on disaster recovery site.Microsoft iSCSI initiator is installed by default on Windows Server 2008 R2, Windows 7, Windows Vista, and Windows Server 2008. In this case no installation is required, that simplifies significantly the usage process. Yet one important comment is that Microsoft iSCSI initiator supports Challenge Handshake Authentication Protocol (CHAP) and Internet Protocol security (IPsec), both of which improve safety of data transmission due to encryption and hash-authentication processes.
As always, there are several best practices recommended for the configuration of a network and Microsoft iSCSI initiator itself. You can find them in the native “Microsoft iSCSI Initiator Step-by-Step Guide”.
new
