Category Archives: VMware

Why VAAI?

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This is Part 2 of my previous blog about VAAI (vStorage API for Array Integration) with more details about VAAI. VAAI offloads some of the I/O related functions to the VAAI-enable storage array, hence giving the hypervisor more compute and memory resource to do it other functions. And the storage array, upon receiving the VAAI command, will execute whatever that is required of it.

Why is VAAI important? What does it do that makes it so useful and important to the hypervisor?

VAAI is about a set of new SCSI commands. And there are 3 important ones:

  • WRITE-SAME
  • XSET
  • ATS

What exactly do these SCSI commands do?

WRITE-SAME is a SCSI command that instructs the storage array to zeroes the virtual VMDK disks or VMFS LUNs. This usually happens when guest OS require a brand new set of virtual disks and initializing the virtual disks is required. In the past (before VAAI), the hypervisor has to repetitively send 0s to the storage to perform the disks zeroing. As shown in the diagram below, you can see that each zero operation is sent from the hypervisor to the storage.

This back-and-forth of sending 0s and acknowledgments between the hypervisor and the storage is not efficient. With VAAI, the command WRITE-SAME  is sent from the hypervisor to the storage array and the storage array will do the zeroing on the disks and LUNs. The hypervisor will not intervene with the process until it gets and acknowledgment of its completion. See diagram below of how VAAI helps in bulk-zeroing of disks and LUNs in the storage array.

The animated GIFs are the taken from Luke Reed’s blog, a fantastic read.

The second VAAI SCSI command is XSET and it performs hardware accelerated full copy. This command is also known as  XCOPY and it offloads the process of copying the blocks of data that makeup a VMDK file. Such copying operations occur when the hypervisor is doing things like VM cloning, Storage vMotion or VM creation from templates (bulk copying to create many similar VMs in one go).

Again with the courtesy of Luke Reed’s animated GIFs, the diagram below shows a full copy without VAAI

and after implementing VAAI, where the full, bulk copy operations is offloaded to the storage array to execute.

The third and last SCSI command of VAAI is ATS or hardware-assisted locking. ATS stands for Atomic, Test and Set and the command allow the hypervisor to lock only the required blocks rather than the entire LUN.

Without VAAI, the entire LUN temporarily could be locked by the numerous VMFS operations of one single hypervisor and this prevents other hypervisors from accessing the shared LUNs. The ATS API offloads lock management from the host to the storage array and keeps the LUN available by locking only required blocks, not the entire VMFS file system. Please see the pleasing diagrams below of

(without VAAI ATS)

(with VAAI ATS)

And if you want to see the VAAI Hardware Accelerated Full Copy (aka XSET) in action, here’s a little video showing how it is done in an EMC environment.

The primary significance and noticeable benefit is definitely performance. The secondary benefit, though not so obvious, is allowing VMware and its hypervisor to scale because it does not get bogged down by some of the I/O functions that it is not meant to do.

There were some new additions in vSphere 5.0 for VAAI. From its FAQ, it listed in ESX5.0, support for NAS Hardware Acceleration is included with support for the following primitives:

  • Full File Clone – Like the Full Copy VAAI primitive provided for block arrays, this Full File Clone primitive enables virtual disks to be cloned by the NAS device.
  • Native Snapshot Support – Allows creation of virtual machine snapshots to be offloaded the array.
  • Extended Statistics – Enables visibility to space usage on NAS datastores and is useful for Thin Provisioning.
  • Reserve Space – Enables creation of thick virtual disk files on NAS.

So, there you have it folks. Why VAAI? Here’s why.

Signs of things to come?

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I wanted to sign off early tonight but an article in ComputerWorld caught my tired eyes. It was titled “EMC to put hardware into servers, VMs into storage” and after I read it, I couldn’t help but to juxtapose the articles with what I said earlier in my blogs, here and here.

It is very interesting to note that “EMC runs vSphere directly on the storage controllers and then uses vMotion to migrate VMs from application servers onto the storage array, ..” since the storage boxes have enough compute power to run Virtual Machines on the storage. Traditionally and widely accepted, VMs should be running on servers. Contrary to beliefs, EMC has already demonstrated this running of VMs capability on their VNX, Isilon and Symmetrix.

And soon, with EMC’s Project Lightning (announced at EMC World in May 2011), they will be introducing server side PCIe-based SSDs, ala Fusion-IO. This is different from the NetApp PAM/FlashCache PCIe-based card, which sits on their arrays, not on hosts or servers. And it is also very interesting to note that this EMC server-side PCIe Flash SSD card will become a bridge to EMC’s FAST (Fully Automated Storage Tiering) architecture, enabling it to place hot, warm and cold data strategically on different storage tiers of the applications on VMware’s VMs (now on either the server or the storage),  perhaps using vMotion as a data mover on top of the “specialized” link created by the server-side EMC PCIe card.

This also blurs the line between the servers and storage and creates a virtual architecture between servers and storage, because what used to be distinct data border of the servers is now being melded into the EMC storage array, virtually.

2 red alerts are flagging in my brain right now.

  1. The “bridge” has just linked the server back to the storage, after years of talking about networked storage. The server is ONE again with the storage. Doesn’t that look to you like a server with plenty of storage? It has come a full cycle. But more interesting and what I am eager to see is what more is this “bridge” capable of when it comes to data management. vMotion might be the first of many new “protocol” breeds to enhance data management and mobility with this “bridge”. I am salivating right now of this massive potential.
  2. What else can EMC do with the VMware API? This capability I am writing right now is made possible by EMC tweaking VMware’s API to maximize much, much more. As the VMware vStorage API is continually being enhanced, the potential is again, very massive and could change the entire landscape of cloud computing and subsequently, the entire IT landscape. This is another Pavlov’s dog moment (see figures below as part of my satirical joke on myself)

 

Sorry, the diagram below is not related to what my blog entry is. Just my way of describing myself right now. 😉

I am extremely impressed with what EMC is doing. A lot of smarts and thinking go into this and this is definitely signs of things to come. The server and the storage are “merging again”. Think of it as Borg assimilation in Star Trek.

Resistance is futile!

Storage Architects no longer required

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I picked up a new article this afternoon from SearchStorage – titled “Enterprise storage trends: SSDs, capacity optimization, auto tiering“. I cannot help but notice some of the things I have been writing about VMware being the storage killer and the rise of Cloud Computing which take away our jobs.

I did receive some feedback about what I wrote in the past and after reading the SearchStorage article, I can’t help but feeling justified. On the side bar, it wrote:

 

“The rise of virtual machine-specific and cloud storage suggest that other changes are imminent. In both cases …. and would no longer require storage architects and managers.”

Things are changing at an extremely fast pace and for those of us still languishing in the realms of NAS and SAN, our expertise could be rendered obsolete pretty quickly.

But all is not lost because it would be easier for a storage engineer, who already has the foundation to move into the virtualization space than a server virtualization engineer coming down to learn about the storage fundamentals. We can either choose to be dinosaur or be the species of the next generation.

More specialized appliances at Oracle OpenWorld

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I was reading the news from Oracle OpenWorld and a slew of news about specialized appliances are on the menu.

Oracle added Big Data Appliance and Oracle Exalytics Business Intelligence Machine to its previous numero uno, Exadata Database Machine. EMC, also announced its Green Plum Data Computing Appliance and also its VNX Unified Storage for Oracle.

As quoted

The EMC VNX Unified Storage for Oracle is a VNX system that has 
Oracle installed in a VMware vSphere virtual machine environment. 
The system is meant to unify all Oracle environments--database over 
Oracle Direct NFS, application servers over NFS, and testing and 
development over NFS--resulting in less disk space used and faster 
testing. EMC says this configuration was made because 50% of Oracle 
customers are virtualizing their systems today.

The VNX Unified Storage for Oracle includes EMC's Fully Automated 
Storage Tiering (FAST) technology, which migrates most frequently 
used data between a primary Fibre Channel drive and solid state drives 
and migrates less frequently used data to Serial ATA (SATA) drives and 
its FAST Cache. In an Oracle environment, FAST is well-suited to 
database applications that generate a large number of random 
inputs-outputs, that experience sudden bursts in user query activity, 
or a high number of user loads and where the entire working set can 
be contained in the solid state drive cache.

Based on testing carried out on an Oracle Real Application Clusters 
(RAC) 11g database that was configured to access the VNX7500 file 
storage over the Network File System (NFS), using the Oracle 
Direct NFS (dNFS) client, results showed an 100% improvement in 
transactions per minute (TPM), 170% improvement in IOPS, and 
a 79% decrease in response time, the company said.

As for GreenPlum, EMC quoted:

The company also is showing off the EMC Greenplum Data Computing 
Appliance(DCA) for Big Data Analytics configuration, which provides 
a new migration path to Greenplum for Oracle Data Warehouse. This 
system includes the Greenplum Data Computing Appliance, EMC's 
Global Data Warehouse, and EMC's IT Business Intelligence Grid 
infrastructure. The EMC Greenplum DCA consists of 8 to 16 segment 
servers running Red Hat Enterprise Linux. Each segment server 
contains 96 to 192 processor cores, with 384 GB to 768 GB of 
memory per segment server. The DCA includes 12 600-GB Serial 
Attached SCSI (SAS) 15K RPM drives for a total useable and 
compressed capacity of 73 TB to 144 TB. The DCA competes with 
Oracle's Exadata Database Machine.

In tests performed with this server/storage configuration and a 
15-TB Oracle Data Warehouse, the DCA processed a 99 million rows 
query in less than 28 seconds vs. seven minutes in a traditional 
Oracle environment and data loads decreased from six days to 29 
minutes

It is getting pretty obvious that specialized appliances are making waves at Oracle OpenWorld but what’s more interesting is the return of a combined and integrated environment of compute and storage as I have mentioned in my previous blog. And I forsee that these specialized appliances will be one of the building blocks of cloud computing together with general purposes platforms such as x86, JBODs and the glue to all these, virtualization, notably VMware.

The rise of the specialized appliance

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Compute and storage are 2 components within the IT infrastructure which are surely converging. SAN and NAS are facing their greatest adversary yet, and could be made insignificant if the cloud and virtualization game had their way. This is giving rise to the a new breed of solution, a specialized appliance where both compute and storage are ONE. Rising from the ashes of shared storage (SAN and NAS, take note), we are beginning to see things going back to way of direct, internal storage.

There were some scuffles in the bushes about 5 years, where Sun (now Oracle) was ahead of its game. The Sun Fire X4500 (aka Thumper) was one of the strong candidates to challenge the SAN/NAS duopoly in this networked storage period. X4500 integrated both the server and the storage components together, using ZFS as a file system and volume manager to deliver a very high throughput on all the JBOD disks very efficiently. ZFS acted as the RAID, so there was no need to have specialized RAID hardware. This proved that a very high performance storage solution can be easily integrated using standard off-the-shelf infrastructure components and the x86 architecture. By combining both compute and storage together, there were hints that the industry was about to rise up to Direct-Attached Storage (DAS) again, despite its perceived weakness against SAN and NAS.

Unfortunately, the applications were not ready for DAS then. Besides ZFS, applications such as databases, emails and file servers were not ready to jump into the DAS bandwagon and watch them ride into the sunset. But the fairy tale seems to be retold again, and this time, the evidence that DAS could rise again is much stronger.

The catalyst to this disruptive force? Virtualization!

I mentioned that VMware is the silent storage killer a few blogs ago. Needless to say, that ruffled a few featheres among the readers. I have no doubt that virtualization is changing how we storage guys look at SAN and NAS. In a traditional setup, the SAN or NAS is setup to provision LUNs or mount points to the data storage for VMFS volumes in the VMware environment. It will then be the storage array to provide snapshots, replications, thin provisioning and so on.

Perhaps VMware is nit picking that managing storage arrays for VMFS volumes is difficult. From the VMware administrators view, they are right. They don’t want to know what’s going on below the VM-level. All they want is storage, any kind of storage and VMware will manage the volumes, snapshots, replication and thin  provisioning. Indeed they were already doing that since vStorage API was introduced. In the new release of VMware version 5.0, the ante has been upped even higher, making networked storage less and less significant.

If you want to know about vStorage API and stuff, below is a diagram of the integration of the various components at the VMware API level.

 

VMware can now use direct, internal storage look like shared storage. The Virtual Storage Appliance (VSA) does just that. VMware already has a thriving market from the community and hobbists for VMware Appliances.

The appliance market has now evolved into new infrastructure too. Using x86 architecture, off-the-shelf infrastructure components (sounds familiar?), companies such as Nutanix and Tintri are taking advantage of this booming trend to introduce specialized VMware appliances as shown in their advertisements on their respective web sites.

Here’s the Nutanix Ad:

 

Here’s the Tintri Ad:

 

Both Tintri and Nutanix are a new breed of appliances – specialized appliances for VMware.

At the same time, other applications are building these specialized appliances as well. I have mentioned Oracle Exadata many times in the past and Oracle Exadata is the perfect example an a fine-tuned, hardcore database engine to make the Oracle run at the best performance possible.

Likewise HP has announced their E5000 Messaging System for Microsoft Exchange. The E5000 is a specialized appliance optimized and well-tuned for the Microsoft Exchange Server 2010. From the words of HP,

“HP E5000 Messaging System is the industry’s first fully self-contained platform built for the next-generation of Microsoft Exchange to deliver enterprise-class messaging to businesses of all sizes. Built as a turnkey solution that can be up and running in a few hours vs. days, the HP E5000 Messaging System gives business users the experience they want most: large mailboxes, centralized archiving of mailboxes files and 24×7 access from any device. IT staffs benefit the solutions simplicity to setup, scale and manage and to meet new demands affordably. Ideal for multi-site enterprises as well as branch office and remote office environments, each HP Messaging System delivers greater simplicity and accelerates deployment with preconfigured solutions starting at 500 mailboxes up to 3000 mailboxes, while delivering large, 1 to 2.5GB mailbox sizes. Clients can grow by adding storage capacity or more appliances within the environment up from hundreds to thousands of mailboxes.”

What are the specs of this E5000 box, you say? Here you go:

 

And look at Row#2 in the table above … Direct, Internal Disks! Look at Row #4, Xeon CPUs! Both Compute and Storage in the same appliance!

While the HP E5000 announcement was recently, Hitachi Data Systems were already in the game early with their Unified Compute Platform and their Converged Platform for Microsoft Exchange with relatively the same idea – specialized appliances.

Perhaps the HDS solutions aren’t exactly direct, internal storage but the concept is still the same – specialized appliance. HDS Unified Compute Platform (UCP) has these components.

 

HDS Converged Platform for MS Exchange provides their specialized “appliance” with Reference Architectures that can support up to 68,000 Microsoft Exchange mailboxes. Here’s an architecture diagram of their “appliance”

 

There’s no denying that the networked storage landscape is changing. So are the computing platforms. We are already seeing the compute and storage components being integrated together, tighter than ever. The wave is rising for specialized appliances and it can only get more intense from now on.

No wonder HP’s Converged Infrastructure vision is betting on x86 architecture, simple storage platforms with SAS/SATA disks and Virtualization. Other vendors are doing the same as well – Cisco, NetApp and VMware with their FlexPod solution and EMC with their VBlocks of VMware, Cisco and EMC Storage.

Hail to the Rise of the Specialized Appliance!

VMware – the silent storage killer

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When VMware 5.0 was launched last month, I heard the feature called Virtual Storage Appliance (VSA) was finally out and is now being offered as an SMB/SME “storage” solution. In my mind, alarm bells were ringing because in its own stealthy manner, VMware had just become a storage player.

What VMware is offering is “Hey! If you don’t have money to buy your enterprise storage array, don’t worry. Make your own shared storage with our very own VMware VSA“. VSA utilizes the internal disks of the ESX/ESXi host as its shared storage.

VSA is nothing new. For years, LeftHand Networks had one for its engineers to do demo and show the functionality of their solution. EMC had it too, and recently I found out that NetApp has its own VSA, but only resell through its partner, Fujitsu. I am not 100% sure about the NetApp thing and I need a NetApp guy to verify this.

Smaller players, but not insignificant, such as Nutanix, Nexenta and Tintri are already offering their own versions and implementation of VSA to their customers, each with its own uniqueness and differences. With the release of the VMware VSA into the open, we shall see all the big storage players offering their VSAs to VMware, like natives offering sacrifices to VMware God. Or perhaps, it has already begun. It is ala-Nexus 1000v all over again.

VMware has become a huge juggernaut and it is merely using its advantage to consolidate the storage component under its control. When VMware version 4.0 came out, vStorage API was introduced along with VAAI (vStorage API for Array Integration). VAAI was created to enhance the storage experience by offloading specific storage operations to the native features of that supported storage platform. That’s all I know about VAAI at this moment, but with this feature, the storage array is tightly integrating its platform to VMware, or should I say … quietly ensnared by VMware tentacles of doom! (Evil laugh in the background! Mua ha ha ha ….!)

In the recently past VMworld, this storage story is slowly being unfurled even more to the world. VASA (vStorage API for Storage Awareness) was recently announced and EMC’s COO Pat Gelsinger spoke about the tighter integration (that word again!) that blurs the administration domain of the VMware admin and the storage admin. Below is a video of Pat Gelsinger talking about VASA below (this is long 55 minute video – Click only if you have the time).

Mind you, the entire vStorage API is still evolving as VMware 5.0 rolls out but here’s the thing. VMware has come out and say that the storage world about LUNs, RAID groups and mount points are a level below what the VMware admin should be concerned about. VMware admins handles their storage at the VM level or as VMDK and therefore, anything below it is of little significance to them. Again, you can see that VMware is using its muscle to say “If you guys want to play, you have to play by my rules“.

So, some new announcements came out from VMworld for storage such as Capacity Pools, I/O Multiplexer, and Storage DRS (Storage Distributed Resource Management) and also an enhanced version (probably more storage resilient) SRM (Site Recovery Manager). All these are being managed at a level above the traditional storage admin level and VMware has said that the VMware admin would be able to carve out a VM volume with its own set of default storage properties, defined snapshot retentions, replication and perhaps even compression and deduplication. But all these will be happening at the VM volume or VMDK level, not a level below that.

Details are still sketchy at this point in time and we probably won’t see these GA until probably VMware version 6.0. But the inertia has been rocked quietly and the VMware storage momentum will gain strength as time passes by. We could see that VMware would just need JBOD (just a bunch of disks) because it has its own enterprise storage features through its vStorage APIs or its future storage specifications. We have seen it happening in VSA with VMware offering its own storage.

From the similar news, what surprised me was what was quoted as shown below.

The presenters said VMware developed the APIs with EMC, NetApp, Dell,
IBM and Hewlett-Packard,but they began the session with a disclaimer
that none of those vendors has committed to support the APIs in
their arrays.

Why the hell would EMC, NetApp, Dell, IBM and HP do something like that?!! Don’t they know that this could contribute to their insignificance in the future?

I am still perplexed but as the whole thing is still evolving, VMware seems to be only obvious winner here.