EMC ViPR software defined object storage part III

Storage I/O trends

This is part III in a series of posts pertaining to EMC ViPR software defined storage and object storage. You can read part I here and part II here.

EMCworld

More on the object opportunity

Other object access includes OpenStack storage part Swift, AWS S3 HTTP and REST API access. This also includes ViPR supporting EMC Atmos, VNX and Isilon arrays as southbound persistent storage in addition.

object storage
Object (and cloud) storage access example

EMC is claiming that over 250 VNX systems can be abstracted to support scaling with stability (performance, availability, capacity, economics) using ViPR. Third party storage will be supported along with software such as OpenStack Swift, Ceph and others running on commodity hardware. Note that EMC has some history with object storage and access including Centera and Atmos. Visit the micro site I have setup called www.objectstoragecenter.com and watch for more content to be updated and added there.

More on the ViPR control plane and controller

ViPR differs from some others in that it does not sit in the data path all the time (e.g. between application servers and storage systems or cloud services) to cut potential for bottlenecks.

ViPR architecture

Organizations that can use ViPR include enterprise, SMB, CSP or MSP and hosting sites. ViPR can be used in a control mode to leverage underlying storage systems, appliances and services intelligence and functionality. This means ViPR can be used to complement as oppose to treat southbound or target storage systems and services as dumb disks or JBOD.

On the other hand, ViPR will also have a suite of data services such as snapshot, replication, data migration, movement, tiering to add value for when those do not exist. Customers will be free to choose how they want to use and deploy ViPR. For example leveraging underlying storage functionality (e.g. lightweight model), or in a more familiar storage virtualization model heavy lifting model. In the heavy lifting model more work is done by the virtualization or abstraction software to create an added value, however can be a concern for bottlenecks depending how deployed.

Software defined, storage hypervisor, virtual storage or storage virtualization?

Most storage virtualization, storage hypervisors and virtual storage solutions that are hardware or software based (e.g. software defined) implemented what is referred to as in band. With in band the storage virtualization software or hardware sits between the applications (northbound) and storage systems or services (southbound).

While this approach can be easier to carry out along with add value add services, it can also introduce scaling bottlenecks depending on implementations. Examples of in band storage virtualization includes Actifio, DataCore, EMC VMAX with third-party storage, HDS with third-party storage, IBM SVC (and their V7000 Storwize storage system based on it) and NetApp Vseries among others. An advantage of in band approaches is that there should not need to be any host or server-side software requirements and SAN transparency.

There is another approach called out-of-band that has been tried. However pure out-of-band requires a management system along with agents, drivers, shims, plugins or other software resident on host application servers.

Example of generic fast path control path model

ViPR takes a different approach, one that was seen a few years ago with EMC Invista called fast path, control path that for the most part stays out of the data path. While this is like out-of-band, there should not be a need for any host server-side (e.g. northbound) software. By being a fast path control path, the virtualization or abstraction and management functions stay out of the way for data being moved or work being done.

Hmm, kind of like how management should be, there to help when needed, out-of-the-way not causing overhead other times ;).

Is EMC the first (even with Invista) to leverage fast path control path?

Actually up until about a year or so ago, or shortly after HP acquired 3PAR they had a solution called Storage Virtualization Services Platform (SVPS) that was OEMd from LSI (e.g. StorAge). Unfortunately, HP decided to retire that as opposed to extend its capabilities for file and object access (northbound) as well as different southbound targets or destination services.

Whats this northbound and southbound stuff?

Simply put, think in terms of a vertical stack with host servers (PMs or VMs) on the top with applications (and hypervisors or other tools such as databases) on top of them (e.g. north).

software defined storage
Northbound servers, southbound storage systems and cloud services

Think of storage systems, appliances, cloud services or other target destinations on the bottom (or south). ViPR sits in between providing storage services and management to the northbound servers leveraging the southbound storage.

What host servers can VIPR support for serving storage?

VIPR is being designed to be server agnostic (e.g. virtual or physical), along with operating system agnostic. In addition VIPR is being positioned as capable of serving northbound (e.g. up to application servers) block, file or object as well as accessing southbound (e.g. targets) block, file and object storage systems, file systems or services.

Note that a difference between earlier similar solutions from EMC have been either block based (e.g. Invista, VPLEX, VMAX with third-party storage), or file based. Also note that this means VIPR is not just for VMware or virtual server environments and that it can exist in legacy, virtual or cloud environments.

ViPR image

Likewise VIPR is intended to be application agnostic supporting little data, big data, very big data ( VBD) along with Hadoop or other specialized processing. Note that while VIPR will support HDFS in addition to NFS and CIFS file based access, Hadoop will not be running on or in the VIPR controllers as that would live or run elsewhere.

How will VIPR be deployed and licensed?

EMC has indicated that the VIPR controller will be delivered as software that installs into a virtual appliance (e.g. VMware) running as a virtual machine (VM) guest. It is not clear when support will exist for other hypervisors (e.g. Microsoft Hyper-V, Citrix/XEN, KVM or if VMware vSphere with vCenter or simply on ESXi free version). As of the announcement pre briefing, EMC had not yet finalized pricing and licensing details. General availability is expected in the second half of calendar 2013.

Keep in mind that the VIPR controller (software) runs as a VM that can be hosted on a clustered hypervisor for HA. In addition, multiple VIPR controllers can exist in a cluster to further enhance HA.

Some questions to be addressed among others include:

How and where are IOs intercepted?
Who can have access to the APIs, what is the process, is there a developers program, SDK along with resources?
What network topologies are supported local and remote?
What happens when JBOD is used and no advanced data services exist?
What are the characteristics of the object access functionality?
What if any specific switches or data path devices and tools are needed?
How does a host server know to talk with its target and ViPR controller know when to intercept for handling?
Will SNIA CDMI be added and when as part of the object access and data services capabilities?
Are programmatic bindings available for the object access along with support for other APIs including IOS?
What are the performance characteristics including latency under load as well as during a failure or fault scenario?
How will EMC place Vplex and its caching model on a local and wide area basis vs. ViPR or will we see those two create some work together, if so, what will that be?

Bottom line (for now):

Good move for EMC, now let us see how they execute including driving adoption of their open APIs, something they have had success in the past with Centera and other solutions. Likewise, let us see what other storage vendors become supported or add support along with how pricing and licensing are rolled out. EMC will also have to articulate when and where to use ViPR vs. VPLEX along with other storage systems or management tools.

Ok, nuff said (for now)

Cheers gs

Greg Schulz – Author Cloud and Virtual Data Storage Networking (CRC Press), The Green and Virtual Data Center (CRC Press) and Resilient Storage Networks (Elsevier)
twitter @storageio