This will also be interesting to watch where along with how other Cisco partners such as EMC, Microsoft, NetApp, VCE and VMware participate. Keep in mind that some of these and other Cisco partners also have their own public, private and hybrid cloud initiatives, services along with being a supplier to each other.
VMware VSAN Software Defined Storage
Another industry activity involving servers storage I/O networking hardware software and virtualization (aka software defined) was the general announcement (GA) by VMware of Virtual SAN (VSAN). VMware VSAN went into public beta shortly after VMworld 2013 timeframe when many of us downloaded, installed and did various types of testing with it.
For those not familiar with VSAN, it is added licensed software functionality for VMware that creates a cluster to host Virtual Machines (VMs) along with its own shared resilient storage solution (e.g. Software Defined Storage). How VSAN works is to use PCIe, SAS, SATA dedicated direct attached storage (DAS) including that are local to the VMware host server (physical machine or PM). The VMware host PMs support DAS Hard Disk Drives (HDD), Solid State Devices (SSD) including PCIe cards, drives or DIMMs, along with Solid State Hybrid Drives (SSHD). This local DAS storage is served and shared among the nodes (up to 32 host or PMs) per VSAN cluster balancing performance, availability (and resiliency) along with space capacity to host VM objects. Note that VM objects include VMDKs (e.g. virtual disks) and are not to be confused with the other type of object storage or access such as CDMI/SWIFT/S3/HTTP/REST.
VMs (and those managing them) see in the VSAN cluster datastores that are familiar with other VMware implementations including storage policies and other tools. Here is a link to a great piece by Patrick Schulz a data infrastructure systems engineer in Germany (no relation, at least not that I know of yet) where he shares his experiences with VSAN implementation.
Generic VSAN example
Instead of using an external iSCSI, Fibre Channel (FC) or FC over Ethernet (FCoE) shared SAN or NAS storage system / appliance to create the storage repository, local DAS is leveraged in groups spread across the hosts in the VSAN cluster (up to 32 nodes ). VSAN requires a percentage of SSD for each storage group on the host cluster nodes that a part is used for caching data which is persistently stored on HDD based media.
VSAN software is licensed by the number of active sockets (not the cores) in the host servers (PM) that are in the cluster or by number of VDI users (guest VMs). For example if there are four servers two with one socket and two with dual sockets there would be six socket licenses. MSRP License cost per processor socket is $2,495 USD which also assumes core VMware licenses already exist. There are also a per guest VM license of $50 per VDI instance, as well as other optional license models and bundles with different features or upgrades.
What is different with VSAN vs. other VMware clusters is that a) the storage is only accessible to VMs that are in the VSAN cluster (unless a VM exports and serves to others via NFS, iSCSI, etc which is a different conversation for another day). Another difference is that today VSAN leverage storage inside of servers or direct attached as opposed to using iSCSI, FC, FCoE SAN or NAS storage systems.
Btw, the current maximum LUN, volume or target storage device size is 4TB so if you were thinking of taking a SAS attached storage system and creating a bunch of small LUNs, you might want to review that from a cost perspective, or at least for today.
There is much more to VSAN including how it works, what it can and can not do, who it is for and whom should not use for different app’s, however IMHO besides lower-end, SMB, workgroup, departmental, VMware centric environments, the number one scenario today is VDI along with where converged solutions such as those from Nutanix, Simplivity and Tintri among others are playing.
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