Over on the Tivoli Storage Blog, there is an exchange over the concept of a "Storage Hypervisor". This started with fellow IBMer Ron Riffe's blog post [Enabling Private IT for Storage Cloud -- Part I], with a promise to provide parts 2 and 3 in the next few weeks. Here's an excerpt:
"Storage resources are virtualized. Do you remember back when applications ran on machines that really were physical servers (all that “physical” stuff that kept everything in one place and slowed all your processes down)? Most folks are rapidly putting those days behind them.
In August, Gartner published a paper [Use Heterogeneous Storage Virtualization as a Bridge to the Cloud] that observed “Heterogeneous storage virtualization devices can consolidate a diverse storage infrastructure around a common access, management and provisioning point, and offer a bridge from traditional storage infrastructures to a private cloud storage environment” (there’s that “cloud” language). So, if I’m going to use a storage hypervisor as a first step toward cloud enabling my private storage environment, what differences should I expect? (good question, we get that one all the time!)
The basic idea behind hypervisors (server or storage) is that they allow you to gather up physical resources into a pool, and then consume virtual slices of that pool until it’s all gone (this is how you get the really high utilization). The kicker comes from being able to non-disruptively move those slices around. In the case of a storage hypervisor, you can move a slice (or virtual volume) from tier to tier, from vendor to vendor, and now, from site to site all while the applications are online and accessing the data. This opens up all kinds of use cases that have been described as “cloud”. One of the coolest is inter-site application migration.
A good storage hypervisor helps you be smart.
Application owners come to you for storage capacity because you’re responsible for the storage at your company. In the old days, if they requested 500GB of capacity, you allocated 500GB off of some tier-1 physical array – and there it sat. But then you discovered storage hypervisors! Now you tell that application owner he has 500GB of capacity… What he really has is a 500GB virtual volume that is thin provisioned, compressed, and backed by lower-tier disks. When he has a few data blocks that get really hot, the storage hypervisor dynamically moves just those blocks to higher tier storage like SSD’s. His virtual disk can be accessed anywhere across vendors, tiers and even datacenters. And in the background you have changed the vendor storage he is actually sitting on twice because you found a better supplier. But he doesn’t know any of this because he only sees the 500GB virtual volume you gave him. It’s 'in the cloud'."
Then another IBM blogger, Richard Vining, continued this meme with his post [VMware Data Protection with a Storage Hypervisor
]. There are [different meanings for the word "protect"
], but Richard's usage relates to protecting against unexpected loss. Here's an excerpt:
"Let’s start with a quick walk down memory lane. Do you remember what your data protection environment looked like before virtualization? There was a server with an operating system and an application… and that thing had a backup agent on it to capture backup copies and send them someplace (most likely over an IP network) for safe keeping. It worked, but it took a lot of time to deploy and maintain all the agents, a lot of bandwidth to transmit the data, and a lot of disk or tapes to store it all. The topic of data protection has modernized quite a bit since then.
Fast forward to today. Modernization has come from three different sources – the server hypervisor, the storage hypervisor and the unified recovery manager. The end result is a data protection environment that captures all the data it needs in one coordinated snapshot action, efficiently stores those snapshots, and provides for recovery of just about any slice of data you could want. It’s quite the beautiful thing."
At this point, you might scratch your head and ask "Does this Storage Hypervisor exist, or is this just a theoretical exercise?" The answer of course is "Yes, it does exist!" Just like VMware offers vSphere and vCenter, IBM offers block-level disk virtualization through the SAN Volume Controller(SVC) and Storwize V7000 products, with a full management support from Tivoli Storage Productivity Center Standard Edition.
SVC has supported every release of VMware since the 2.5 version. IBM is the leading reseller of VMware, so it makes sense for IBM and VMware development to collaborate and make sure all the products run smoothly together. SVC presents volumes that can be formatted for VMFS file system to hold your VMDK files, accessible via FCP protocol. IBM and VMware have some key synergies:
- Management integration with Tivoli Storage Productivity Center and VMware vCenter plug-in
- VAAI support: Hardware-assisted locking, hardware-assisted zeroing, and hardware-assisted copying. Some of the competitors, like EMC VPLEX, don't have this!
- Space-efficient FlashCopy. Let's say you need 250 VM images, all running a particular level of Windows. A boot volume of 20GB each would consume 5000GB (5 TB) of capacity. Instead, create a Golden Master volume. Then, take 249 copies with space-efficient FlashCopy, which only consumes space for the modified portions of the new volumes. For each copy, make the necessary changes like unique hostname and IP address, changing only a few blocks of data each. The end result? 250 unique VM boot volumes in less than 25GB of space, a 200:1 reduction!
- Support for VMware's Site Recovery Manager using SVC's Metro Mirror or Global Mirror features for remote-distance replication.
- Data center federation. SVC allows you to seamlessly do vMotion from one datacenter to another using its "stretched cluster" capability. Basically, SVC makes a single image of the volume available to both locations, and stores two physical copies, one in each location. You can lose either datacenter and still have uninterrupted access to your data. VMware's HA or Fault Tolerance features can kick in, same as usual.
But unlike tools that work only with VMware, IBM's storage hypervisor works with a variety of server virtualization technologies, including Microsoft Hyper-V, Xen, OracleVM, Linux KVM, PowerVM, z/VM and PR/SM. This is important, as a recent poll on the Hot Aisle blog indicates that [44 percent run 2 or more server hypervisors]!
For a set of best practices combining VMware with SVC, check out this IBM Redpaper titled [VMware Proof of Practice and Performance Guidelines on the SAN Volume Controller].
Join the conversation! The virtual dialogue on this topic will continue in a [live group chat] this Friday, September 23, 2011 from 12 noon to 1pm EDT. Join me and about 20 other top storage bloggers, key industry analysts and IBM Storage subject matter experts to discuss storage hypervisors and get questions answered about improving your private storage environment.
technorati tags: IBM, Ron Riffe, Richard Vining, Storage Hypervisor, Cloud, Heterogeneous, Virtualization, SVC, Tivoli Storage, Productivity Center, TPC, VMware, vSphere, vCenter, ESX, Unified Recovery, Data Protection, EMC, VPLEX