Continuing this week's theme on Storage Area Networks, today I thought I would talkabout the various terms we use for our equipment.
One area of confusion are the adjectives "entry-level", "midrange" and "ent If you are asking yourself "which size is right for my company?" or "is my company big enoughfor a director?" you are asking the wrong questions! Instead, determine a SAN configurationthat meets your workload, and then decide the components for that design. McData coined a phrase called "core/edge" design that is considered today as "Best Practice" throughout the industry.A good write-up can be found here at SearchStorage.com. Basically, you put your big beefy "core" directors in the center of the room, and then surround it with midrange switches, that then these connect to "edge" switches, that then connect to the servers and storage near them. As you grow, this design can easilyscale to grow with you. So, if you need help implementing a SAN for the first time, or upgrading the one you have,call IBM, we can help!
If you are asking yourself "which size is right for my company?" or "is my company big enoughfor a director?" you are asking the wrong questions! Instead, determine a SAN configurationthat meets your workload, and then decide the components for that design.
McData coined a phrase called "core/edge" design that is considered today as "Best Practice" throughout the industry.A good write-up can be found here at SearchStorage.com. Basically, you put your big beefy "core" directors in the center of the room, and then surround it with midrange switches, that then these connect to "edge" switches, that then connect to the servers and storage near them. As you grow, this design can easilyscale to grow with you.
So, if you need help implementing a SAN for the first time, or upgrading the one you have,call IBM, we can help!Read More]
Last week, Paul Weinberg of eChannelLine.com asks Is this the year of the SAN (again)?So, I thought this week I would cover my thoughts and opinions on storage networking. We oftenfocus on servers or storage devices, and forget that the network in between is an entire worldon itself.
I believe Mr. Weinberg is basing this on the idea that in 2007, over 50 percent of disk will beattached over SAN, edging out the alternative: Direct Attached Storage (DAS). But perhaps 50 percentis the wrong number to focus on. In 2007, The United Nations estimates thatcities will surpass rural areas, with just over 50 percent of theworld's population. Does that make this the "Year of the City"? Of course not.
Instead, I prefer to use the methodology that Malcolm Gladwell uses in his book, The Tipping Point.(I have read this book and highly recommend it!)Gladwell indicates that the tipping point happens at the start of the epidemic, not when it is half over.Isn't it better to celebrate the sweet 16 debutante ball when young ladies have completed their years of training and preparation, and are ready to be introduced to the rest of the world, rather than after they are thirty-something, married with children.
Let's explore some of the history. Stuart Kendric has a nice 7-page summary on theHistory & Plumbing of SANs.
IBM announced the first SAN technology calledEnterprise Systems Connection (ESCON) way back in September 1990. This allowed multiplemainframe servers to connect to multiple storage systems over equipment called "ESCON Directors" that directedtraffic from point A to point B. Before this, mainframes sent "ChannelCommand Words" or CCWs, across parallel "bus and tag" copper cables. ESCON was serial overfiber optic wiring. SANs solved two problems: first, it reduced the "rat's nest" of cables between many serversand many storage systems, and second, it extended the distance between server and storage device.
For distributed systems running UNIX or Windows, the CCW-equivalent over parallel cables was called Small ComputerSystem Interface (SCSI). The SCSI command had over 1000 command words, so for its Advanced Technology (AT) personal computers (PC AT), IBM introduced a subset of SCSI commands called ATA (Advanced Technology Attachment). ATA drives supportedfewer commands, ran at slower speeds, and were manufactured with a less rigorous process. Today ATA drives are about 55 percent the cost per MB as comparable SCSI drives.
Anyone who has ever opened their PC and found flat ribbon cable with eight or sixteen wires in parallel, can understand that the same issues applied externally. Parallel technologies arelimited to distance and speed, as all the bits have to arrive at the end of the wire at approximately thesame time. Direct attach schemes with every server attaches directly to every storage device were also problematic.Imagine 100 servers connected to 100 storage devices, that would be 10,000 wires!
So, a new technology standard was developed, called Fibre Channel, ratified in 1994.The spelling of "Fibre" was intentionally made different than "Fiber" on purpose. "Fibre" is a protocol thatcan travel over copper or glass wires. "Fiber" represents the glass wiring itself.
Fibre Channel is amazingly versatile. For today's Linux, UNIX and Windows servers, it can carry SCSI commands, and the combination of SCSI over FC is called Fibre Channel Protocol (FCP). For the mainframe servers, it can carry CCW commands. Running CCW over Fibre Channel is called FICON. This convergence allows mainframes and distributed systems to share a common Fibre Channel network, using the same set of switches and directors.
We saw the use of SANs explode in the marketplace over the past 10 years, and then cool down with a series of mergers and acquisitions. Last year, Brocade announced it was acquiring rival McData, so we will be down to two major players, Cisco and Brocade.
So, IMHO, I think we are well past the "Year of the SAN".
Continuing this week's theme of New Year's Resolutions for the data center, today we'll talk about one that people don't always think about on a personal level, that is to hone your tools and skills.
A long time ago, I used to be a regular speaker at the SHARE user group conference. One of the most attended sessions was Sam Golob presenting the latest CBT Tape set of tools. Over time, this large collection of "mainframe shareware" was handed out on 3480 tape cartridges, then on CDs, and finally made downloadable off the web.Sam's main point, which I remember to this day, was that everyone who has a job should figure out what tools they use, keep those tools functioning properly, and learn to use them well.
Later, I took some cooking classes at a culinary school. Among other things, we learned:
This last point hits close to home, as many people like me have too many tools that they do not use often enough to know how to use them well. Do I really need my strawberry corer, garlic press, or a tray designed for the storage and delivery of deviled eggs?
The same could be said about software tools. What tools do you use in your job? Do you feel you know how to take full advantage of their power and capabilities?If you develop software, do you know all the features for your debugging tools? If you develop advertising or marketing materials, do you know all the features of your photo or video editing software? If you manage storage in a data center, do you know all the tools for managing your storage area network (SAN), disk systems, tape libraries, and reporting tools to identify all of your files and databases across your entire IT environment?I would not be surprised if you could replace a whole mess of tools with just one, such as the IBM TotalStorage Productivity Center.Read More]
Happy New Year!
This year I resolve to be more consistent in my blogging, and my goal is to give you one to five entries per week, every week, based on the advice from Glenn Wolsey, Jennette Banks, and others.On some weeks, I will have a running theme, so rather than super-long entries to cover everything I can think of on a topic, make the entries short and readable. This week is a good time to review last year's "New Year's Resolutions" and to make new ones for 2007. I will discuss actions that companies can adopt for their data centers.
A common resolution is to lose weight, as in this Dilbert comic. Last year, I resolved to lose weight in 2006, and am delighted with myself that I lost eight pounds. When people ask for the secret of my success, I whisper in their ear "Eat less, exercise more." In general, people (and companies) know what to do, but just don't do it, which Pfeffer and Sutton document in their book The Knowing-Doing Gap. In my case, it involved lifestyle change: I exercised at a gym three times per week in Tucson, with a personal trainer, and revamped my diet.
Not everyone subscribes to the "eat less exercise more" philosophy. For example, Ric Watson argues in his blog that you can eat fewer calories, but eat more in actual volume, by choosing the right foods. This brings up the issues of "metrics" that most data centers are familiar with. Last year, I read the book "You: On a Diet" which explains that it is better to focus on "waist reduction" as measured in inches around your mid-section at the belly button, than "weight reduction" as measured in pounds. This year, I resolve to get down to 35 inches by the end of 2007.
The problem with measuring "weight" is that you are weighing bones, muscle and fat. A person can gain ten pounds of muscle, lose ten pounds of fat, and the scale would indicate no progress. The same problem occurs in data centers. How many TB of data do you have? Storage admins can easily tell you, but can they tell how much of this is bone (data needed for operating infrastructure), muscle (data used in daily operations that generates revenue) or fat (obsolete or orphaned data)?
We at IBM often state that "Information Lifecycle Management (ILM)" is more lifestyle change than a "fad diet". Figuring out what data you should capture in the first place, where to place it, when to move it, and when to get rid of it, is more important that just buying different tiers of storage hardware. So, for those looking to make new data center resolutions, I suggest the following actions:
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For those of us in the northern hemisphere, yesterday was this year's Winter Solstice, representingthe shortest amount of daylight between sunrise and sunset. So today, I thought I would blog on my thoughtsof managing scarcity.
Earlier in my career, I had the pleasure to serve as "administrative assistant" to Nora Denzel for the week at a storage conference. My job was to make her look good at the conference, which if you know Nora, doesn't take much. Later, she left IBM to work at HP, and I gotto hear her speak at a conference, and the one thing that I remember most was her statement that thewhole point of "management" was to manage scarcity, as in not enough money in the budget,not enough people to implement change, or not enough resources to accomplish a task.(Nora, I have no idea where you are today, so if you are reading this, send me a note).
Of course, the flip-side to this is that resources that are in abundance are generallytaken for granted. Priorities are focused on what is most scarce. Let's examine some of theresources involved in an IT storage environment:
This last point brings me back to the concept of food, and I am not talking about doughnuts in the conference room, or pizza while making year-end storage upgrades. I'm talking aboutthe food you work so hard to provide for yourself and your family. The folks at Oxfam came up with a simpleanalogy. If 20 people sit down at your table, representing the world’s population:
Happy Winter Solstice!
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