One does not simply do scalable HA NAS

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Panzura – Distributed Locking & Cloud Gateway for CAD

I have been watching the multi-site distributed NAS space for some years now. There have been some interesting products including Netapp’s Flexcache which looked nice but never really seemed to get market traction, and similarly IBM Global Active Cloud Engine (Panache) which was released as a feature of SONAS and Storwize V7000 Unified. Microsoft have played on the edge of this field more successfully with DFS Replication although that does not handle locking. Other technologies that encroach on this space are Microsoft Sharepoint and also WAN acceleration technologies like Microsoft Branchcache and Riverbed.

What none of these have been very good at however is solving the problem of distributed collaborative authoring of large complex multi-layered documents with high performance and sturdy locking. For example cross-referenced CAD drawings.


It’s no surprise that the founders of Panzura came from a networking background (Aruba, Alteon) since the issues to be solved are those that are introduced by the network. Panzura is a global file system tuned for CAD files and it’s not unusual to see Panzura sites experience file load times less than one tenth or sometimes even one hundredth of what they were prior to Panzura being deployed.

Rather than just provide efficient file locking however, Panzura has taken the concept to the Cloud, so that while caching appliances can be deployed to each work site, the main data repository can be in Amazon S3 or Azure for example. Panzura now claims to be the only proven global file locking solution that solves cross-site collaboration issues of applications like Revit, AutoCAD, Civil3D, and Bentley MicroStation as well as SOLIDWORKS CAD and Siemens NX PLM applications. The problems of collaboration in these environments are well-known to CAD users.


Panzura has been growing rapidly, with 400% revenue growth in 2013 and they have just come off another record quarter and a record year for 2014. Back in 2013 they decided to focus their energies on the Architectural, Engineering & Construction (so-called AEC) markets since that was where the technology delivered the greatest return on customer investment. In that space they have been growing more than 1000% per year.

ViFX recently successfully supplied Panzura to an international engineering company based in New Zealand. If you have problems with shared CAD file locking, please contact ViFX to see how we can solve the problem using Panzura.


IBM Software-defined Storage

The phrase ‘Software-defined Storage’ (SDS) has quickly become one of the most widely used marketing buzz terms in storage. It seems to have originated from Nicira’s use of the term ‘Software-defined Networking’ and then adopted by VMware when they bought Nicira in 2012, where it evolved to become the ‘Software-defined Data Center’ including ‘Software-defined Storage’. VMware’s VSAN technology therefore has the top of mind position when we are talking about SDS. I really wish they’d called it something other than VSAN though, so as to avoid the clash with the ANSI T.11 VSAN standard developed by Cisco.

I have seen IBM regularly use the term ‘Software-defined Storage’ to refer to:

  1. GPFS
  2. Storwize family (which would include FlashSystem V840)
  3. Virtual Storage Center / Tivoli Storage Productivity Center

I recently saw someone at IBM referring to FlashSystem 840 as SDS even though to my mind it is very much a hardware/firmware-defined ultra-low-latency system with a very thin layer of software so as to avoid adding latency.

Interestingly, IBM does not seem to market XIV as SDS, even though it is clearly a software solution running on commodity hardware that has been ‘applianced’ so as to maintain reliability and supportability.

Let’s take a quick look at the contenders:

1. GPFS: GPFS is a file system with a lot of storage features built in or added-on, including de-clustered RAID, policy-based file tiering, snapshots, block replication, support for NAS protocols, WAN caching, continuous data protection, single namespace clustering, HSM integration, TSM backup integration, and even a nice new GUI. GPFS is the current basis for IBM’s NAS products (SONAS and V7000U) as well as the GSS (gpfs storage server) which is currently targeted at HPC markets but I suspect is likely to re-emerge as a more broadly targeted product in 2015. I get the impression that gpfs may well be the basis of IBM’s SDS strategy going forward.

2. Storwize: The Storwize family is derived from IBM’s SAN Volume Controller technology and it has always been a software-defined product, but tightly integrated to hardware so as to control reliability and supportability. In the Storwize V7000U we see the coming together of Storwize and gpfs, and at some point IBM will need to make the call whether to stay with the DS8000-derived RAID that is in Storwize currently, or move to the gpfs-based de-clustered RAID. I’d be very surprised if gpfs hasn’t already won that long-term strategy argument.

3. Virtual Storage Center: The next contender in the great SDS shootout is IBM’s Virtual Storage Center and it’s sub-component Tivoli Storage Productivity Center. Within some parts of IBM, VSC is talked about as the key to SDS. VSC is edition dependent but usually includes the SAN Volume Controller / Storwize code developed by IBM Systems and Technology Group, as well as the TPC and FlashCopy Manager code developed by IBM Software Group, plus some additional TPC analytics and automation. VSC gives you a tremendous amount of functionality to manage a large complex site but it requires real commitment to secure that value. I think of VSC and XIV as the polar opposites of IBM’s storage product line, even though some will suggest you do both. XIV drives out complexity based on a kind of 80/20 rule and VSC is designed to let you manage and automate a complex environment.

Commodity Hardware: Many proponents of SDS will claim that it’s not really SDS unless it runs on pretty much any commodity server. GPFS and VSC qualify by this definition, but Storwize does not, unless you count the fact that SVC nodes are x3650 or x3550 servers. However, we are already seeing the rise of certified VMware VSAN-ready nodes as a way to control reliability and supportability, so perhaps we are heading for a happy medium between the two extremes of a traditional HCL menu and a fully buttoned down appliance.

Product Strategy: While IBM has been pretty clear in defining its focus markets – Cloud, Analytics, Mobile, Social, Security (the ‘CAMSS’ message that is repeatedly referred to inside IBM) I think it has been somewhat less clear in articulating a clear and consistent storage strategy, and I am finding that as the storage market matures, smart people are increasingly wanting to know what the vendors’ strategies are. I say vendors plural because I see the same lack of strategic clarity when I look at EMC and HP for example. That’s not to say the products aren’t good, or the roadmaps are wrong, but just that the long-term strategy is either not well defined or not clearly articulated.

It’s easier for new players and niche players of course, and VMware’s Software-defined Storage strategy, for example, is both well-defined and clearly articulated, which will inevitably make it a baseline for comparison with the strategies of the traditional storage vendors.

A/NZ STG Symposium: For the A/NZ audience, if you want to understand IBM’s SDS product strategy, the 2014 STG Tech Symposium in August is the perfect opportunity. Speakers include Sven Oehme from IBM Research who is deeply involved with gpfs development, Barry Whyte from IBM STG in Hursley who is deeply involved in Storwize development, and Dietmar Noll from IBM in Frankfurt who is deeply involved in the development of Virtual Storage Center.

Melbourne – August 19-22

Auckland – August 26-28

My name is Storage and I’ll be your Server tonight…

Ever since companies like Data General moved RAID control into an external disk sub-system back in the early ’90s it has been standard received knowledge that servers and storage should be separate.

While the capital cost of storage in the server is generally lower than for an external centralised storage subsystem, having storage as part of each server creates fragmentation and higher operational management overhead. Asset life-cycle management is also a consideration – servers typically last 3 years and storage can often be sweated for 5 years since the pace of storage technology change has traditionally been slower than for servers.

When you look at some common storage systems however, what you see is that they do include servers that have been ‘applianced’ i.e. closed off to general apps, so as to ensure reliability and supportability.

  • IBM DS8000 includes two POWER/AIX servers
  • IBM SAN Volume Controller includes two IBM SystemX x3650 Intel/Linux servers
  • IBM Storwize is a custom variant of the above SVC
  • IBM Storwize V7000U includes a pair of x3650 file heads running RHEL and Tivoli Storage Manager (TSM) clients and Space Management (HSM) clients
  • IBM GSS (GPFS Storage Server) also uses a pair of x3650 servers, running RHEL

At one point the DS8000 was available with LPAR separation into two storage servers (intended to cater to a split production/non-production environment) and there was talk at the time of the possibility of other apps such as TSM being able to be loaded onto an LPAR (a feature that was never released).

Apps or features?: There are a bunch of apps that could be run on storage systems, and in fact many already are, except they are usually called ‘features’ rather than apps. The clearest examples are probably in the NAS world, where TSM and Space Management and SAMBA/CTDB and Ganesha/NFS, and maybe LTFS, for example, could all be treated as features.

I also recall Netapp once talking about a Fujitsu-only implementation of ONTAP that could be run in a VM on a blade server, and EMC has talked up the possibility of running apps on storage.

GPFS: In my last post I illustrated an example of using IBM’s GPFS to construct a server-based shared storage system. The challenge with these kinds of systems is that they put onus onto the installer/administrator to get it right, rather than the traditional storage appliance approach where the vendor pre-constructs the system.

Virtualization: Reliability and supportability are vital, but virtualization does allow the possibility that we could have ring-fenced partitions for core storage functions and still provide server capacity for a range of other data-oriented functions e.g. MapReduce, Hadoop, OpenStack Cinder & Swift, as well as apps like TSM and HSM, and maybe even things like compression, dedup, anti-virus, LTFS etc., but treated not so much as storage system features, but more as genuine apps that you can buy from 3rd parties or write yourself, just as you would with traditional apps on servers.

The question is not so much ‘can this be done’, but more, ‘is it a good thing to do’? Would it be a good thing to open up storage systems and expose the fact that these are truly software-defined systems running on servers, or does that just make support harder and add no real value (apart from providing a new fashion to follow in a fashion-driven industry)? My guess is that there is a gradual path towards a happy medium to be explored here.

Building Scale-out NAS with IBM Storwize V7000 Unified

If you need scalable NAS and what you’re primarily interested in is capacity scaling, with less emphasis on performance, and more on cost-effective entry price, then you might be interested in building a scale-out NAS from Storwize V7000 Unified systems, especially if you have some block I/O requirements to go with your NAS requirements.

There are three ways that I can think of doing this and each has its strengths. The documentation on these options is not always easy to find, so these diagrams and bullets might help to show what is possible.

One key point that is not well understood is that clustering V7000 systems to a V7000U allows SMB2 access to all of the capacity – a feature that you don’t get if you virtualize secondary systems rather than cluster them.

V7000U Cluster

V7000U Virtualization

V7000U Active Cloud

And of course systems management is made relatively simple with the Storwize GUI.


NAS Metadata – Sizing for SONAS & Storwize V7000U

Out there in IBM land the field technical and sales people are often given a guideline of between 5% and 10% of total NAS capacity being allocated for metadata on SONAS or Storwize V7000 Unified systems. I instinctively knew that 10% was too high, but like an obedient little cog in the machine I have been dutifully deducting 5% from the estimated nett capacity that I have sized for customers – but no more!

Being able to size metadata more accurately becomes especially important when a customer wants to place the metadata on SSDs so as to speed up file creation/deletion but more particularly inode scans associated with replication or anti-virus.

[updated slightly on 130721]

The theory of gpfs metadata sizing is explained here and the really short version is that in most cases you will be OK with allowing 1 KiB per file per copy of metadata, but the worst case metadata sizing (when using extended attributes, for things like HSM) should be 16.5 KiB * (filecount+directorycount) * 2 for gpfs HA mirroring.


  • if you have 20,000 files and directories the metadata space requirement should be no more than 16.5 * 20,000 * 2 = 660,000 KiB = 645 MiB
  • if you have 40 million files and directories the metadata space requirement should be no more than 16.5 * 40,000,000 * 2 = 1,320,000,000 KiB = 1.23 TiB

So why isn’t 5% a good assumption? What I am tending to see is that average file size on a general purpose NAS is around 5MB rather than the default assumption of 1MB or lower. 

So it’s more important to have a conservative estimate of your filecount (and directory count) than it is to know your capacity.

The corollary for me is that budget conscious customers are more likely to be able to afford to buy enough SSDs to host their metadata, because we may be talking 1% rather than 5%.

Note:  When designing SSD RAID sets for metadata, SONAS/V7000U/gpfs will want to mirror the metadata across two volumes, so ideally those volumes should be on different RAID sets.

Because of the big difference between the 16.5 * formula and the 5% to 10% guideline I’d be keen to get additional validation of the formula from other real users of Storwize V7000 Unified or SONAS (or maybe even general gpfs users). Let me know what you are seeing on your own systems out there. Thanks.

What do you get at an IBM Systems Technical Symposium?

What do you get at an IBM Systems Technical Symposium? Well for the event in Auckland, New Zealand November 13-15 I’ve tried to make the storage content as interesting as possible. If you’re interested in attending, send me an email at and I will put you in contact with Jacell who can help you get registered. There is of course content from our server teams as well, but my focus has been on the storage content, planned as follows:

Erik Eyberg, who has just joined IBM in Houston from Texas Memory Systems following IBM’s recent acquisition of TMS, will be presenting “RAMSAN – The World’s Fastest Storage”. Where does IBM see RAMSAN fitting in and what is the future of flash? Check out RAMSAN on the web, on twitter, on facebook and on youtube.

Fresh from IBM Portugal and recently transferred to IBM Auckland we also welcome Joao Almeida who will deliver a topic that is sure to be one of the highlights, but unfortunately I can’t tell you what it is since the product hasn’t been announced yet (although if you click here you might get a clue).

Zivan Ori, head of XIV software development in Israel knows XIV at a very detailed level – possibly better than anyone, so come along and bring all your hardest questions! He will be here and presenting on:

  • XIV Performance – What you need to know
  • Looking Beyond the XIV GUI

John Sing will be flying in from IBM San Jose to demonstrate his versatility and expertise in all things to do with Business Continuance, presenting on:

  • Big Data – Get IBM’s take on where Big Data is heading and the challenges it presents and also how some of IBM’s products are designed to meet that challenge.
  • ProtecTIER Dedup VTL options, sizing and replication
  • Active/Active datacentres with SAN Volume Controller Stretched Cluster
  • Storwize V7000U/SONAS Global Active Cloud Engine multi-site file caching and replication

Andrew Martin will come in from IBM’s Hursley development labs to give you the inside details you need on three very topical areas:

  • Storwize V7000 performance
  • Storwize V7000 & SVC 6.4 Real-time Compression
  • Storwize V7000 & SVC Thin Provisioning

Senaka Meegama will be arriving from Sydney with three hot topics around VMware and FCoE:

  • Implementing SVC & Storwize V7000 in a VMware Environment
  • Implementing XIV in a VMware Environment
  • FCoE Network Design with IBM System Storage

Jacques Butcher is also coming over from Australia to provide the technical details you all crave on Tivoli storage management:

  • Tivoli FlashCopy Manager 3.2 including Vmware Integration
  • TSM for Virtual Environments 6.4
  • TSM 6.4 Introduction and Update plus TSM Roadmap for 2013

Maurice McCullough will join us from Atlanta, Georgia to speak on:

  • The new high-end DS8870 Disk System
  • XIV Gen3 overview and tour

Sandy Leadbeater will be joining us from Wellington to cover:

  • Storwize V7000 overview
  • Scale-Out NAS and V7000U overview

I will be reprising my Sydney presentations with updates:

  • Designing Scale Out NAS & Storwize V7000 Unified Solutions
  • Replication with SVC and Storwize V7000

And finally, Mike McKenzie will be joining us from Brocade in Australia to give us the skinny on IBM/Brocade FCIP Router Implementation.

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