Thursday, December 10, 2009

Virtualized Storage - Get all the features of the SAN without paying for SAN

We all know the benefits of  virtualization and consolidation in the server area and similarly you can achieve a lot more productivity, efficiency, TCO and ROI by consolidation of your local DAS storage by putting it in a central location and provisoning it from there as it leads to less wastage and more utilization with better storage management and deduplication along with capacity management.  However not every Enterprise Business can afford a SAN though this does not imply that they won't benefit out of SAN but we all know that traditional Fibre channel storage comes very costly and requires a dedicated storage area network comprising of dual FC HBA cards on all hosts, switches and dedicated storage Like HP EVA/XP, EMC Clarrion/Symmetrix and trained administrative staff. So what shall you propose when you know that the Enterprise for which you are designing a solution or may be your own Enterprise IT cost center would not like to fund budget for SAN.

Get all the features of the SAN without paying for SAN

Last few years have seen a considerable growth in use of ISCSI technology as an answer to costly traditional SAN storage. The benefits of the iscsi are that it does not require a dedicated costly fabric switch and HBA network as it utilizes existing ethernet network. Data blocks flow over existing ethernet network through dedicated network without interupting the network packet traffic which leads to cost savings and saves you from allocation of huge budget for SAN infrastructure. You can use iscsi storage technology in many scalable ways depending on your needs for example Microsoft storage server acting as a NAS box, Starwind ISCSI target software , HP Lefthand and Dell Equallogic [both fall under category of premium ISCSI SAN]. In this article i am going to talk about HP Lefthand ISCSI based SAN and the features and advantages it has over traditonal SAN storage. Both Dell Equallogic and HP Lefthand have very similar features and are competitors in market.

While traditional Fibre Channel SANs require a separate physical infrastructure to for storage networks, HP P4000 SANs go wherever your Ethernet network reaches. The use of ISCSI technology—SCSI over standard Internet Protocol (IP)—reduces costs and helps IT organizations to realize the vision of connecting every server to high-performance, shared, block-based storage. Few features of HP Lefthand P4000 SANs which make them so attratcive are provided below:

  • Storage clustering and inbuilt synchronus mirroring
  • Network RAID
  • Thin Provisioning, Snapshots and smartclones
  • Remote Copy  
  • Deduplication
  • Performance increases in lock step with its storage capacity.
  • HP P4000 device-specific module (DSM) for the Microsoft Windows Multipath I/O (MPIO) iSCSI plug-in.
  • Certified for interoperability with Microsoft applications including Microsoft Exchange, Microsoft SQL Server, Microsoft SharePoint and Microsoft Hyper-V
  • Certified to integrate with VMware vSphere software
  • HP P4000 SANs work with VMware Site Recovery Manager to respond fast and accurately to disasters that are geographic in scope and also support Microsoft Cluster shared volumes in multi site clustering.
The best feature of the HP Left hand storage is its scalability without reducing the performance output. In traditional storage you can add disk enclosures but cannot add controllers, cache and processing power which means as you keep on adding the disk enclosures performance will dip down which is not the case for HP Lefthand SAN.

If at any point of time you need more capacity you can provision more storage nodes without effecting the performance as opposite to traditional storage. Each storage node contributes its own disk drives, RAID controller, cache, memory, CPU, and networking resources to the cluster.

Another great feature is lun thin provisoning and snapshots/smartclones which helps in deduplicating leading to saving in your storage consumption and increased efficiency for storage utilization. A fully provisioned volume has its blocks pre-allocated, while a thin-provisioned volume has none. Thin provisioning, combined with the ability to scale storage clusters dynamically, allows customers to purchase only the storage they need today, and to add more storage to the cluster as application data grows. Thin Provisioning eliminates the need for up-front capacity reservations, helping to raise utilization levels, efficiency, and ROI all while reducing energy consumption and carbon footprint.This feature also enables you to provision disaster recovery and also take smart backups using Microsoft VSS as HP Lefthand SAN is fully integrated and capable of taking advantage of VSS functionality. SmartClone feature uses the snapshot mechanism to clone volumes instantly for use by new virtual or physical servers. The feature turns any volume or snapshot into one or many full, permanent, read-write volumes. Volume clones use copy-on-write semantics to avoid copying or duplicating data, making SmartClone an instant, space-efficient mechanism that also helps to increase storage utilization and improve storage ROI.

Network RAID is built-in synchronous mirroring that protects data and allows configuration of availability levels on a per-volume basis rather than a per-storage-system basis. Network RAID dictates how a logical volume’s blocks are laid out across the cluster, providing reliability that can be configured on a per-volume basis to best meet application and data requirements. Depending on a logical volume’s Network RAID level, 1, 2, 3, or 4 copies of each of the volume’s data blocks are synchronously replicated and striped across the storage nodes in a cluster. Network RAID is a per-volume attribute, so changing a volume’s RAID level is a simple operation that does not cause any interruption in service. When one or more new storage nodes are added to a cluster, Network RAID re-arranges the striping and replication scheme for the volumes to include the new nodes. Unlike traditional storage products, HP P4000 SANs can do this while remaining continuously online.

At end of all the discussion performance is most important point and 10-Gigabit Ethernet connectivity to the storage nodes eliminates the network as the source of bottlenecks. Delivering performance far superior to 2, 4, and even 8 Gbps Fibre Channel networks, optional dual 10 Gigabit Ethernet interfaces on each storage node deliver up to 20 Gbps of storage bandwidth per node. This clears the very myth that FC based storage provides better performance than ISCSI based storage. However the most important point is yet to be discussed and that is the cost benefits of using ISCSI storage and you can see here what people are saying about it. ISCSI storage based solutions are costing 1/4th of the traditional Enterprise storage solutions and there are many other cost benefits as mentioned here   and here Another interesting benefit is mixing your FC Storage network with ISCSI storage network for achieving the best out of both worlds. For some of your loads do not really require high performance and throughput and can be directed on low costing ISCSI storage and other on High end FC Enterprise storage leading you saving costs and bringing better ROI. Hope you find this article interesting and was a reading pleasure and once again thanks for your time.

For More Information on HP lefthand network, please refer to HP website


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