When is a gigabyte not a gigabyte? When you're not buying gigabytes!

I stepped into a hornet nest this week when I posted a write-up about a new flash storage array from Pure Storage. The controversy had nothing to do with the underlying technology, which seems quite sound. Rather, it was all about pricing, with Pure’s competitors calling foul on their price comparisons.

You’re Not Buying Gigabytes

In a world of 3 TB drives, storage capacity is almost irrelevant. Capacity is what people think they are getting when they buy enterprise storage devices, but capacity is only one aspect of the purchase, and it’s not a very significant one in most cases.

So what are enterprise storage buyers buying?

• Performance, especially I/O operations (IOPS), is much more critical than capacity in most cases, and it takes lots of spindles or expensive flash chips to deliver it.
• Data protection features like snapshots are increasingly important, and often cost extra.
• Compatibility is paramount, as is long-term supportability from all vendors involved.
• Integration and management features are often the deciding factor in purchases, especially when it comes to server virtualization applications.
• High availability and product support are “must-haves” that can multiply the cost of a solution.
• Power, cooling, and floor space can be very important for some applications and entirely inconsequential in others.
• Capacity is sometimes important, but many applications require just a few TB or less and thin provisioning, data deduplication, and compression are really blurring the lines here.

So although a typical customer will say “I need 200 GB for this application” they likely need nothing of the sort. They really need 100 IOPS, snapshots, a line on the HCL, VAAI and vCenter plugins, and redundant everything. Even the capacity number is questionable: Most applications grow over time, and few need much capacity really.

Since you can’t buy a 1 GB storage array and can’t fill a 10 TB device to 100%, pricing per GB is complete nonsense. Plain old storage space just sort of tags along for the ride once you build a system capable of meeting all these other needs.

Data Reduction or Pricing Obfuscation?

Utilization of storage capacity has always been terrible, but improving capacity efficiency is worthless. The best you can do is over-tax your array or put all your data “eggs” in too few drive “baskets”. Achieving impressive capacity utilization just concentrates I/O, and this is the last thing you want to do with spinning hard disk drives.

This is why I suggest redirecting the conversation away from capacity requirements. The amount of GB to be used and the efficiency of that storage doesn’t matter all that much except for certain massive and rare applications. Once the array is big enough to handle the data, everything else is a wash.

This is also why I’m skeptical of data reduction technologies. Most applications would be better off optimizing for performance not reducing capacity used. And data reduction techniques like compression and deduplication quickly lead down the “your mileage may vary” rat hole.

Comparing Apples to Apples

Also read Grapples and Tangelos: Why it’s Impossible to Compare Fairly

There is only one way to do a real fair comparison between different storage devices: Specify all the requirements and let each vendor put forward whatever they have that meets all of them. Who really cares if vendor A’s disk-based solution is 10% utilized while vendor B’s flash array needs 1/5 the capacity? As long as you have a place to put it (and enough power to feed it) it’ll still work fine.

One serious challenge in enterprise storage is the rise of flash memory as a storage medium. Flash chips are expensive on a data capacity basis but amazingly cheap in terms of performance and environmental efficiency. Put another way, an SSD can’t storage as much data as a hard disk, but it delivers massive I/O capability in a tiny, rugged, low-power footprint.

Since most enterprise applications need only a few hundred GB of capacity, a few SSDs can be a compelling alternative to a “refrigerator” full of disks. It can be hard to convince the boss, but you really can fit a whole datacenter’s worth of storage I/O into a few rack units!

Pure and Nimbus

This is the issue facing flashy solid state devices from many companies, and the root of my headaches this week. Pure Storage hasn’t finalized pricing yet, but are claiming that their new device costs $5 per usable gigabyte. This is incredibly cheap for an array that can blow the doors off most enterprise gear!

Nimbus Data, on the other hand, sells their all-flash enterprise storage array for about $10 per GB. But this is not the end of the story, and Pure might even be more expensive than Nimbus! Or maybe not. It all depends on what you’re comparing.

Pure claims that their cost is half the price of most comparable flash storage array competitors, but this is where the questions start to appear. Is that $5 gigabyte usable or raw? Does it include high availability? And can I really store any old gigabyte of data there or is that a compressed/deduplicated gigabyte?

It turns out that the real cost of Pure Storage capacity is $20 per GB including RAID and an extra mirrored array for high availability. But since every byte written to the array is thin provisioned, deduplicated, and compressed, many customers will pay much less for actual data stored. And since it’s an all-SSD array, it’ll perform way better than a disk-based system, too.

Muddying the Waters

So why not just call it $5 per GB and be done with it? It’s confusing, that’s why, and your mileage will vary widely.  Pure’s own slides show some applications getting 4:1 data reduction and others all the way up to 17:1. So these applications would be paying as low as $1.18 per GB or as high as $5.

But you can’t buy just 1 GB of storage from Pure. Their smallest array (which includes one controller and one shelf of SSDs) provides 5.5 TB of raw capacity, presumably using 24 256 GB SSDs. A high-availability configuration would include two controllers and two shelves of SSDs for 11 TB of raw storage. That’s going to cost almost a quarter of a million dollars according to my calculator. That’s one expensive gigabyte!

Of course no one would buy this array to store just a thousand megabytes. They would buy it to support a bunch of applications that need capacity and performance and efficiency and integration and everything else. And they can buy a mirrored pair of arrays from Pure Storage or Nimbus or Violin Memory or Texas Memory Systems or others at a variety of price points.

The only way to really compare these products is to spec them out on equal footing and see what the price tag looks like. These comparisons would include data reduction, but they would also have to bring in high availability and every other requirement of the applications they will support.

Stephen’s Stance

It’s way too difficult for me to do the pricing math for these systems, so I’m throwing in the towel. I’m thrilled to see all-flash arrays made available to IT buyers. This wouldn’t be possible without clever use of thin provisioning and data reduction, as well as smart software to overcome the limits of SSD.

I’m going to guess that Pure and Nimbus will cost about the same for similar configurations, though I’ll bet each believes they’re cheaper. Rather than get in the middle, I invite each company to post a comment below stating their case. I’ll even embed their responses into a future blog post on the subject if they get too long. Just don’t ask me to be the referee.

Update: Pure Storage responds with an outline of their pricing:

• How Pure Storage Delivers All-Flash Storage at Below the Price of Spinning Disk

Image credit: Rotten Apple by Wappas

© sfoskett for Stephen Foskett, Pack Rat, 2011. | When Pricing Gets Squishy Competition Heats Up
This post was categorized as Enterprise storage, Personal, Virtual Storage. Each of my categories has its own feed if you'd like to filter out or focus on posts like this.

Thin provisioning is a topic that is interesting to me. Now, I have to warn you ahead of time that I’ve been a critic of thin provisioning for a long, long time. So, you’re really not going to get a big cheer leader “rah rah” session here.

I feel like too many people use technologies like thin provisioning more for political and management problems than technical problems. But recently I have come around to seeing that thin provisioning has good uses. It has some positive aspects. But, I’ve also discovered a lot about how it really is and how it really works, and it’s not quite as wonderful as people like to say.

But, let’s start at the beginning. Why are we doing this at all? Why do we care about thin provisioning? This is why: Storage is not getting cheaper.

If you went to buy a disk ten years ago, you’re going to spend about the same as would today, but you’re going to get a lot more capacity – a lot more capacity!

This is a big fallacy of enterprise storage. I used to call it the CompUSA problem, but then they went out of business. So, I guess I’ll have to call it the Best Buy problem. The idea that I can go into a store and buy two terabytes of disk for two $100 bills and have change left over.

Well, that’s an issue for enterprise storage, right? Because what happens when you try to actually do real enterprise storage provisioning in a corporation? You end up with people pushing back on you saying, “Hey, wait! How come you’re charging me so much? For the price that I’m paying per month in internal chargebacks I can just go buy this capacity. And I have to pay that every single month?”

I hear this again and again from a lot of the pundits (people who don’t actually do anything in storage) who say, “ah, it’s just a spinning disk. All the enterprise guys they’re bending you over and taking advantage of you, and they are taking too much money out of your pocket for all this.”

Well, the truth is that probably a lot of them are overpricing. But, in my opinion, the cost of capacity is basically irrelevant. That doesn’t mean it’s zero, but it’s basically irrelevant. The reason is that everything else about storage is growing so rapidly that the dropping cost of disk capacity really isn’t helping.

The fact is that we have terrible utilization of enterprise resources anyway, and it’s not getting any better. In fact, most companies today have about the same storage utilization that they did ten years ago. Somewhere between 20 and 30 percent, if you look soup to nuts.

It hasn’t improved because they are “doing storage” the same way. If you’ve got file systems and you’ve got SCSI and you’ve got block storage and all that kind of stuff, guess what? Your utilization is going to be just as bad now as it was then because the technology just isn’t there.

And often it’s the business processes: There is a big problem with how provisioning, forecasting, purchasing, and the rest is done. So, storage costs just keep rising, and the dropping cost of disk capacity is only a minimal component.

Let’s talk about real-world cost. This is a graph that I made for one customer, and it doesn’t necessarily represent everybody. I’m not IDC. I don’t have some kind of universal numbers. I don’t know if they have the universal numbers either, but I definitely don’t.

This is what I found. With hardware and software, it was less than 10 percent of the entire cost of delivering storage services.

What does that mean? That means that if you reduce the cost and hardware and software by 50 percent (which would be a tremendous win by anybody’s standards) you’ve then affected your cost of storage by just five percent.

That’s basically irrelevant. You work really hard to do all this stuff and you’re really not getting anything.

For the next segment of this discussion, we’ll take a look at storage utilization.

© sfoskett for Stephen Foskett, Pack Rat, 2010. | Storage is Not Getting Cheaper
This post was categorized as Computer History, Enterprise storage, Gestalt IT. Each of my categories has its own feed if you'd like to filter out or focus on posts like this.

You’re Holding It Wrong

How can I make this fantastic offer without knowing anything about your environment and without including any asterisks? Simply because when it comes to data storage, in the immortal words of Steve Jobs, you’re holding it wrong. In 15 years of enterprise storage consulting, I have never seen a single environment using anything close to their total usable capacity. In fact, I’ve never seen an environment that was using even half of its usable capacity.

This makes my job easy. If you have a half dozen storage arrays with a total of 500 TB of raw storage, about 60% of that capacity will be usable (once you take RAID, spares, and other overhead into account). Of the remaining 300 TB of capacity, you’re probably only storing 70 TB of data if you’re like the average enterprise shop. So I can just hand you a report that says “write 35 TB more” and walk out. My job will be done.

But let’s say you’re better than average. Let’s say you run a really tight ship and don’t waste expensive capacity like most people. I bet you’ve still got slack capacity you don’t know about. Maybe a project manager demanded a 30 TB LUN for his new database and won’t let you run your monitoring tools to see what he’s really using. Or perhaps another project never got off the ground but they won’t share the disk space “they paid for.” Then there is that other system that was turned off without you knowing, so the storage is still allocated. There’s always plenty of perfectly-good free usable primary storage capacity.

Wringing Out the Slack

See my post, Use Process Solutions For Process Problems, Technical Solutions For Technical Ones

Despite what the warring vendors might say, the issue isn’t the equipment or software you’re using, the issue is the way you’re using it. Storage isn’t bought as an integrated piece of a compute environment these days, and it isn’t managed that way, either. Enterprise storage arrays are purchased in fits and starts, a little here and a lot there, according to the whims of the budget and project planning process. It’s not at all unusual to see tight storage constraints delaying projects even as a new and totally unused array sits idle in the corner.

The root cause lies with how capacity is purchased, configured, allocated, and charged to projects, not with the technical capabilities of the platform. Nearly every modern array can be shared by many servers, and nearly every environment has ample storage networking potential. Are Fibre Channel directors and HBAs to expensive? Switch to iSCSI or NAS! Every server has a spare gigabit Ethernet port or two, and I bet your networking guys have a decent switch you could use.

All this applies mainly to primary storage, but backups are an equal opportunity. Most daily incremental backup tapes are left half-empty due to job scheduling, connectivity, and inappropriate manual media assignments. And those jam-packed weekly full tapes are probably a waste of time and capacity, too. How about re-thinking your backup process with fewer fulls, virtual tape, elimination of useless data, or even snapshots? I bet my friend W. Curtis Preston could offer some great advice there!

Stephen’s Stance

You don’t need to get crazy to wring out a bit more storage capacity. Deduplication and data optimization sound great, but what’s the point if you’ve got ample unused capacity already? Aren’t all these guarantees just an attempt to grab more business, more money, and sell more gear?

The leading cause of poor storage capacity utilization is failure to use storage capacity!

I’m serious about the offer. I’ve done exactly this kind of work before and have the resources to do it for you, too. Bring me in and I’ll give you a plan to write 50% more primary data. Guaranteed success or you don’t pay. But I bet you could do the same thing without me!

© sfoskett for Stephen Foskett, Pack Rat, 2010. | Stephen Foskett’s 50% Free Capacity Guarantee!
This post was categorized as Enterprise storage, Virtual Storage. Each of my categories has its own feed if you'd like to filter out or focus on posts like this.

Challenges for Enterprise IT

I’ve spent 15 years focused on the business of IT, with a special interest in data storage, since it makes up such a large part of modern information systems and budgets. The current crisis has forced many of us in enterprise IT to focus inward, tackling the tough challenges inside our data centers rather than adding on exciting new capabilities. The priority has shifted from features with a potential for cost avoidance to real current-year cost savings.

Even as budgets are tightening, we continue to pour good money after bad. This happens everywhere, buying too much of what we don’t want or need.

• As the high end marches ever-higher, we find that most applications require lower tiers of capability
• Data center managers are scrambling to control power and cooling costs
• At the same time, utilization of existing resources remains low, especially storage systems

But change is in the air. Enterprise IT is questioning their old assumptions.

• The monolith of IT infrastructure is finally becoming a pyramid, with a small amount of super high-end “tier-0″ capability and a widening reliance on lower tiers of bulk capacity
• Virtualization of servers and storage is having a real impact, enabling mobility of systems, applications, and data across tiers
• Enterprise IT is increasingly offloading non-essential services to outside partners who can deliver focus and economics

A New Challenge for Me

I have always tried to focus my efforts on making a difference in my little corner of the world, so the time has come for me to make a change professionally.

I am pleased to announce that I am joining Nirvanix, where I will be starting a new strategic consulting practice. We will focus on enabling enterprise customers to leverage modern data storage technology for infrastructure transformation. Nirvanix shares my vision of evolved IT infrastructure supported by tiers of applications, servers, and especially storage. Nirvanix moving forward and attacking the storage issues that face enterprise IT head-on!

I pride myself on giving honest and straightforward advice, and this will not change. Nirvanix Consulting will deliver independent and trustworthy advice, and this is exactly what enterprise IT organizations require and demand. Although Nirvanix provides managed offsite storage as a service to enterprise customers, this offering is not the correct answer for every application or business. In discussing this business concept with Nirvanx CEO, Jim Zierick, I stressed that I will certainly sometimes recommend competing solutions, and that the right move for some is reuse of existing assets. Zierick, who was formerly a partner at the respected consultancy, McKinsey, agrees with this independent approach. We must help each client to develop a strategy that is appropriate to their needs.

Although I have a new professional affiliation, my independence and commitment to the storage community will not change. I remain committed to open communication, and will maintain my Pack Rat blog, Gestalt IT, and my other public writing and speaking activities. Now let’s get down to work!

© sfoskett for Stephen Foskett, Pack Rat, 2009. | Changing Times Demand Focus
This post was categorized as Enterprise storage, Personal, Virtual Storage. Each of my categories has its own feed if you'd like to filter out or focus on posts like this.

I'm pleased to have been invited to write and speak on storage topics for a decade

I’m pleased to announce that I will be presenting at all four of TechTarget’s excellent end user-focused 2009 Storage Decisions conferences in North America! I’m also very excited to be developning two entirely new sessions for the show:

1. Tools and Tricks to Manage Capacity – Knowing how much disk capacity you have allocated, how much is actually being used, and what remains are basics for disk storage management. But it can be difficult to measure and describe storage capacity and make smart and effective decisions. In this session, we’ll cover the tools and best practices that are key to managing disk capacity.
2. Radical Tiered Storage to Reduce Cost and Expand Service – “Do more with less” is the slogan of the year, but storage pros have been doing exactly this for years. From HSM to tiered storage, data is moving away from simple disks and landing on flash memory, tape, and cloud services. Adopting an expansive tiered storage policy will not only reduce costs but can also improve performance and introduce new capabilities.

The 2009 show dates have been released, with more information at the official Storage Decisions site. Admission is free for qualified attendees, so register now for the session near you!

• Chicago – June 1-2, 2009
• Toronto – June 16, 2009
• New York – September 22-23, 2009
• San Francisco – November 17, 2009

Long-time readers of this blog know that both topics are top of mind for me, and I’ll be updating this blog and Gestalt IT with content on both capacity management and tiered storage over the coming year as I progress through the development and presentation of this content.

I spent the last two years presenting on the topics of storage virtualization and email archiving, and previously presented a two-hour “storage 101″ session. Although I loved that content, I’m never satisfied with my own work, so I’ll be happy to develop these two new presentations from scratch!

© sfoskett for Stephen Foskett, Pack Rat, 2009. | Two New Storage Decisions Sessions for 2009: Capacity Management and Radical Tiered Storage!
This post was categorized as Everything. Each of my categories has its own feed if you'd like to filter out or focus on posts like this.

Disk Inventory X is an amazing tool to zoom into your full disk and figure out what's taking up all the space!

I’m not an inherently tidy person. That’s one reason that I upgraded my MacBook Pro’s hard disk to 320 GB! But as a storage and data management consultant, I generally keep my computers much cleaner than my office.

So I was surprised to see a pop-up window on my Mac telling me that my hard drive was full! It was time to investigate data management applications for OS X. Luckily, I found some great tools, and these helped me isolate the space-wasting items quickly and easily.

This post is part of my series focused on Apple OS X tips and tricks.

• Access NTFS Volumes On Your Mac
• Clean Up Your Mac! Essential OS X Tidiness Tools and Techniques
• How To Move OS X Time Machine Backups To A New Disk
• Hallelujah! OS X Can Reduce PDF File Size!
• Custom Drive Icons in Mac OS X
• OS X Custom Drive Icons 2: Boot Camp and NTFS

Who’s To Blame?

When it comes to data storage, out of sight is usually out of mind. The primary culprit in the rampant over-saving of data is a lack of perspective and visualization: We tend to focus on the items we think are at fault rather than the true space wasters.

Consider your PC or Mac: Do you really know what is taking up all of your disk space? Unless you have a good tool, the answer is probably not. You might think that your “Documents” folder takes up most of the room, since you use it all the time and it has so many files in it. But even the bloated files produced by Microsoft Office pale in comparison to multimedia photo, music, and video files. And it is usually the folders that you don’t actively manage that are the worst space-wasters!

All operating systems have their secret corners that fill up with cruft, and many applications do a terrible job of cleaning up after themselves. In my PC days, I used to use Glary Utilities to clean out the corners of Windows and the awesome treemapping visualizations in WinDirStat to find where my storage was going. But since switching to my Mac I wasn’t aware of similar utilities.

Mapping the Tree

Let’s back up for a minute. Treemapping is an incredibly slick way to quickly zoom in on capacity problems. It divides up a rectangular region into color-coded blocks sized according to some factor for easy visualization. In this case, every file on a hard disk is represented according to its size and colorized by type. See the image at the top of the post for an example, using data from my laptop’s OS X drive.

I created this map with the awesome free Disk Inventory X application, which scans any drive connected to an OS X machine (even a NFS or CIFS share) and creates an interactive treemap. GrandPerspective is a similar app, but I like DI better after trying both.

One glance at the treemap and the eye is drawn to the large aqua file (my iPhoto library, all 25 GB of it) and the multitude of blue and red video files. File types are listed on another inspector, ordered in descending order of size, allowing me to see that I had more than 100 GB of TV shows and movies on my drive, and these made up the bulk of my “missing” space!

Click on a block, and DI displays the file as well as its location in the tree. We can then navigate up and down to locate other areas of wasted space, and DI highlights the current file or folder in the treemap to give a visual representation of what it contains.

Cruft

I found lots of junk (cruft) stored on my Mac:

• The Downloads folder seems like a junk magnet. I tend to open downloaded items from Safari’s Downloads window rather than using Finder, but when you select Remove From List there, it leaves the file in the Downloads folder. Even if you try to police your Safari download junk you can miss a few files. So this has to be the first place to look for cruft in OS X!
• I love how OS X installs apps - in many cases with a simple drag and drop to the Applications folder. But regardless of the install method, old dmg, iso, and pkg files seem to find their way onto my disk. Most of them are in Downloads, but I have found ‘em in lots of places.
• iTunes is particularly egregious, keeping every downloaded iPhone update package in ~/Library/iTunes/iPhone Software Updates. I had 1.3 GB of files sitting there! It’s a good idea to keep the current one around in case you need to restore your phone, but the old ones are just junk. This applies equally in Windows, by the way!
• When you double-click on a zip file in Finder, it expands the whole thing wherever you are, unlike Windows which lets you browse the zip without expanding it. I found quite a few of these weird folders all over my Documents folder, where I had opened a zip to have a look and left behind the entire contents.
• I keep my desktop clean, but I bet most people have at least a few gigs of junk hanging out there!
• VMware, Parallels, and VirtualBox create massive virtual disk files, and these can often auto-grow, becoming space vampires without your knowledge. Be careful if you’re using these apps!
• I’ve got two complete sets of my mail folders created by OS X Mail. I’m not sure why, but am shy to actually delete one.
• Don’t forget your external USB and FireWire drives, too! I deleted over 500 GB of redundant data from four external drives with a total capacity of just 1.3 TB!

Like any computer, Macs have to be periodically cleaned up. I’m keeping my eyes on the above areas using Disk Inventory X. What works for you?

© sfoskett for Stephen Foskett, Pack Rat, 2009. | Clean Up Your Mac! Essential OS X Tidiness Tools and Techniques
This post was categorized as Apple, Personal, Terabyte home. Each of my categories has its own feed if you'd like to filter out or focus on posts like this.

First, let’s clarify just which products and capabilities Symantec is offering here:

• Veritas Storage Foundation version 5.0MP3 for Unix/Linux includes SmartMove and the Thin Reclamation API
• Veritas Storage Foundation for Windows 5.0 only includes SmartMove at this point, but it will be updated to include Thin Reclamation at some point in the coming year

Although there is no real information on Symantec’s web site about all this yet, Symantec’s director of Storage Management and High Availability, Sean Derrington, assures me that their software is available now. Although no compatible arrays are in end-user hands, 3PAR will update their T-Class firmware to support the API shortly, and HDS and HP are on the way as well.

Thin Aware Software

Next, contrary to what I inferred from the announcement, there is no native thin provisioning capability in the file system or volume manager. So the first item in my list is right out. However, the volume manager is now “thin aware”, which means that it will communicate up to the file system and down to the array to coordinate more effective use of space.

When the volume manager is used with Veritas File System (VxFS) on UNIX or NTFS on Windows Server 2003 or 2008, it will automatically keep track of deleted files and will pass this information down the stack to the array. This is a major piece of functionality to add, especially to NTFS, “hole punching” (like NetApp) to maximize thin provisioning.

The Storage Foundation tools have also been updated to properly report on thin provisioned volumes. For example, the following screenshot shows three disk devices where encl1 supports thin reclamation and encl0 does not.

# vxdisk list
DEVICE        TYPE   DISK          GROUP         STATUS
encl0_0       auto   encl0_0       mydg online   thin
encl1_0       auto   encl1_0       mydg online   thinrclm
encl1_1       auto   ecnl1_1       mydg online   thinrclm

Thin Reclamation API

The Veritas Thin Reclamation API allows the Storage Foundation volume manager and file systems to communicate with thin-capable arrays when data is deleted on thin-ified LUNs, maintaining their thin-ness as you go. When a file is deleted, the file system will communicate to the volume manager that that space is no longer needed. When the server administrator runs the “vxdisk reclaim” or “fsadm –R” commands, the volume manager will communicate this information to the array (using SCSI commands) that any vacated disk blocks can now be reclaimed. Symantec expects folks to set up a cron job to reclaim space, or perhaps just run it when they see the need.

This is brilliant stuff, and ought to make thin provisioning shine in terms of array utilization. In an environment of thin-enabled Veritas volumes and supported storage arrays, the amount of space used on an array will be awfully close to the amount of space used in the file systems. This is a massive win - a capacity gain of on the order of 50%-70% in an average environment!

For more on this topic, see my recent post on storage utilization

If the storage array fully supports Symantec’s API, the tools will also report physically allocated storage behind thin and thin_reclaim devices.

# vxdisk –o thin list
DANAME        DISK SIZE(Mb)        PHYS_ALLOC(Mb)       DISK GROUP TYPE
encl0_0       2000                 50 mydg              thin
encl1_0       200                  50 mydg              thinrclm
encl1_1       500                  500 mydg             thinrclm

SmartMove

SmartMove is Symantec’s new capability for online migration from “thick” to thin LUNs. It is included in Storage Foundation for Unix/Linux and Windows and works with any thin storage array, not just those that support the API. This is basically a tweak to the old storage migration support we have all known and relied on in Veritas Storage Foundation for over a decade, except that it’s smart enough to not request blocks that it won’t use. One could theoretically “SmartMove” a volume regularly to reclaim space without using the API at all, but those commands are sure a lot simpler.

Note that SmartMove speeds up migration too, even for thick volumes! When you use a SmartMove-enabled version of Storage Foundation to move a volume, it will only send the blocks that have changed over the wire. This reminds me a little of VMware’s new I/O deduplication capability talked about at VMworld, but it’s focused only on migrations, not other I/O situations.

For more on this topic, see my recent post on VMware vStorage

The Plot Thickens

So I was wrong about one item, but the other two remain true. Is Symantec’s new capability a winner? I give it a silver medal – it’s good stuff, but some issues remain.

1. My primary concern remains – thin provisioning does nothing to address the lack of storage management that is so prevalent. It enables greater utilization of capacity, but does nothing to control how that capacity is used. This isn’t a beef with Symantec’s Veritas Storage Foundation or 3PAR or HDS or EMC or anyone in the thin industry, really. Instead, it is a wake-up call to all of the storage organizations out there who have filesystems full of uncontrolled junk!
2. My second concern is the lack of capacity management. Thin provisioning is a lie, promising more capacity than is available. This might be acceptable in certain controlled circumstances like operating system or application volumes, but telling end users that they have plenty of available space is a recipe for disaster. Storage use is like air – it expands to fill all available volume. Without capacity management, your thin volumes will be “overdrawn” and your storage “account” will be bankrupt.
3. Then there is the issue of proprietary APIs versus standards. Let me say right away that I always support standards over proprietary technology. But, at the same time, given the choice between nothing and something, I’ll take the proprietary API. Thin provisioning is a good idea with poor implementation. This API helps to make it useful in the real world, and having a market leader like Symantec behind it makes it all the more relevant. I certainly hope the entire storage industry will come up with a standard thin API, and when that happens I hope Symantec will support it. Until then, at least we have something.

I will be writing more about thin provisioning in the coming weeks. Until then, I continue to applaud Symantec, 3PAR, HDS, and HP for their work in making this technology somewhat more practical. Now how about VMware, Microsoft, Sun, and the Linux guys get some thin technology going, too?

See my posts on Gestalt IT for similar enterprise IT infrastructure commentary

© sfoskett for Stephen Foskett, Pack Rat, 2008. | Symantec’s Thin API: The Plot Thickens
This post was categorized as Enterprise storage, Virtual Storage. Each of my categories has its own feed if you'd like to filter out or focus on posts like this.

I’ve just finished my day in Charlotte on my Storage Virtualization Seminar tour for TechTarget. We had another great crowd – everyone seemed interested even if some were shy about speaking up. I was especially pleased to see the optimism about the city’s post-Wachovia future.

Comments at the event focused on management, with my concerns about ownership and intra-departmental conflict rising from consolidation of server, I/O, and storage really getting attention.

Some highlights from the crowd:

• Satisfaction with IBM SAN Volume Controller (SVC) remains high. There were some large SVC users in the audience, and they have no complaints.
• Users are becoming aware of FCoE – the group here in Charlotte raised the first questions and comments I’ve heard yet from end-users.
• VMware is in use almost everywhere, but the folks were interested in Hyper-V, Xen, and Virtual Iron as well.
• Interest in deduplication and thin provisioning was also high, with many questioning the performance and space claims but overall optimism.
• Some talk turned towards retention policies, archiving, and how to control the use of storage systems.
• Everyone was clamoring for better metrics and clearer descriptions of system capability, particularly around storage utilization.

Congratulations to the winners of the TechTarget, Dell, and Agilisys giveaways!

If you were at the show and gave me your card, I’ll send the presentation PDF to you as soon as I get a better (faster) connection. If not, please drop me a line and I’d be happy to add you to the list.

My virtualization talk comes to Toronto next, and a shortened version will be presented at Storage Decisions San Francisco in November.

© sfoskett for Stephen Foskett, Pack Rat, 2008. | Storage Virtualization Charlotte: Thoughts and Reactions
This post was categorized as Enterprise storage, Personal, Virtual Storage. Each of my categories has its own feed if you'd like to filter out or focus on posts like this.

Based on Floral Matryoshka by BrokenSphere/Wikimedia Commons

My February 2003 column for Storage magazine focused on the surprising difficulty of measuring storage utilization. I wrote:
 

“A true measurement of utilization would reflect every layer of usage metrics – from raw disk in a shared array to used storage within files. Raw storage for each new frame of reference is contained within the used storage measured above it, so low utilization is compounded as we move deeper into the stack.”

In that column, I suggested that utilization of any resource was based on just three metrics:

1. Raw
2. Usable
3. Used

But this is confounded by the frame of reference being measured. It’s trivially simple to determine the raw, usable, and used capacity for a storage array, server, or database. But what happens when one tries to measure storage utilization all the way through the stack?

When vendors take up this challenge, the discussion tends to get diverted into a cul-de-sac that presents their products most favorably, as was the case of Chuck Hollis’ comparison of his EMC CLARiiON to HP’s and NetApp’s storage products. Was Chuck wrong? Was HP right? Or was it NetApp that has the best utilization? One thing is certain, we’re getting nowhere if we can’t agree on some basic terminology.

Chris Evans' Storage Waterfall

Credit Storage Architect Chris Evans with seeing the problem for what it was. He noticed the matryoshka effect and put together a “waterfall” diagram, showing how low utilization is compounded as we move down the stack. He also notes that complexity rises as we move to the right, something I never called out.

We were both onto the same thing, though, and my study of storage utilization (published in the April 2003 issue) supported his suggestion that the raw to used ratio might be as little as 10:1 on average. At the time, I even put together a similar waterfall chart, but it was never published outside the company I worked for (that I know of).

So I fully and enthusiastically support Chris’ ideas on this topic! Let’s come up with some standard metrics for the various places that storage can be “raw, usable, and used”:

1. Disk drive units often have excess space (raw), and this is especially true of enterprise flash units
2. RAID sets definitely follow this pattern
3. Storage arrays themselves can have unused usable space (as noted by Marc Farley)
4. Storage virtualization can add another layer of utilization loss
5. On the host side, we must consider volume managers which can perform all the functions of an array
6. Filesystems also have raw, usable, and used space
7. As do applications that manage storage like databases
8. Add in capacity management technologies like compression and deduplication to really mess things up
9. Finally, server virtualization can sit above or below these server variables, and virtual machines themselves often have unused space.

Simply put, there are a lot of places for a few unused bytes to hide. Anyone want to bet that 10:1 is optimistic? And we’re only talking about capacity utilization – there are whole other worlds of power efficiency and performance to consider as well…

© sfoskett for Stephen Foskett, Pack Rat, 2008. | The Storage Utilization Waterfall: Raw, Usable, and Used
This post was categorized as Enterprise storage, Virtual Storage. Each of my categories has its own feed if you'd like to filter out or focus on posts like this.