Product Reviews

There may be plenty of storage vendors implementing support for iSCSI in their SAN and NAS appliances, but an increasingly popular alternative is the option to pick your own hardware platforms and storage devices. There are a number of software solutions available. FalconStor's iSCSI Storage Server for Windows 2 particularly impresses with its ease of use, but DataCore's SANmelody aims to deliver the best value along with a top range of features.

The base version of SANmelody on review supports two ports, which are the physical or virtual network adaptor ports on the server running the software. FalconStor's base product has a limit of 16 host or initiator connections, whereas SANmelody supports unlimited host connections. Network storage options are endless, since SANmelody can use virtually any internal or external hard disk - if Windows can see it then SANmelody can use it. Drives are made ready from the Disk Administrator but should be basic disks that haven't been formatted or given a drive letter.

As an MMC (Microsoft management console) snap-in, SANmelody is accessed directly from the Computer Management interface. Initially, the configuration process seems complex, but after a few goes you should get the hang of it. Each system that's to access the network storage is called an application server, and you need to go to each one and log its iSCSI initiators into the

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storage server. This allows it to see and display available channels that are then assigned to the appropriate application server objects. Each prepared disk partition is then declared as a virtual volume that needs to be mapped to selected application servers. This way, you can strictly control access from host systems to the network storage, as only those that have the volume mapped will be able to use the storage.

Along with linear drives, which are targets created from single raw partitions, SANmelody provides optional support for storage pools that can comprise multiple physical drives. Called NMVs (network managed volumes), these can present virtual volumes to application servers that are much larger than the physical size of the combined disks. Virtual volumes up to 2TB in size can be created, and SANmelody's auto-provisioning feature keeps an eye on the physical amount of space being used and dynamically allocates disk blocks as required. Data is striped across disk members and physical space can be increased on-demand by adding extra drives to the storage pool.

To test SANmelody, we installed it on a dual Xeon Windows Server 2003 system and used three 36GB Ultra320 SCSI hard disks for our network storage. We created a virtual volume on the remaining raw space on the first drive. We then placed the other two in a storage pool and created multiple virtual volumes, each 2TB in size. From another Server 2003 system, we used Microsoft's iSCSI initiator 2 software to log on to the storage server. Raw read performance over Gigabit Ethernet was good. Iometer configured with two workers and 64KB sequential requests reported 88MB/sec, which compares very well with FalconStor and also many hardware appliances.

SANmelody is clearly well worth considering for those who want iSCSI but don't want to be tied to a hardware vendor. It delivers very good performance, offers a host of optional features and the higher-end versions uniquely support Fibre Channel.