The first article in a five-part series looks at various types of storage management software, including storage resource management, SAN management, and storage virtualization.
By David Czech
There are many challenges associated with the ups and downs of storage and storage management (see figure). While many aspects of data storage are growing rapidly, just as many are shrinking.
What does all of this growing and shrinking mean to IT professionals who are tasked with monitoring, managing, and maintaining storage infrastructures? They must grow more efficient, lean, reliable, accurate, and faster, while shrinking budget, headcount, and human errors.
Are your storage administration tasks largely repetitive multiple-step processes? Is considerable time spent gathering data for utilization-based chargebacks? How long does it take to perform all of the zoning, provisioning, and configuration necessary to allow servers to access storage? Should the server/application/architecture teams even be asking for more storage when the capacity allotted far exceeds the capacity actually used? How much online storage will you get back if you move all files that haven't been accessed for 18 months to tape, and how will you move them? How close to capacity are the inter-switch links?
If you are unsure of the answers to any of these questions, it is very likely that some sort of storage management software would be worth your time and money.
This series of five articles is intended to help you better understand the tools available to assist you in getting a grip on storage management. The articles will delve into:
- The categories of tools that are available;
- The needs that each of these categories addresses;
- The differentiators you should look for when comparing products in each category;
- How the products work; and
- Why you should buy storage management software instead of just hiring more staff.
This article will help to explain the main categories of storage management tools and how each of these categories is important, in varying degrees, to taming the storage management beast.
Storage resource management (SRM) tools (the subject of the next article in this series) can help with the task of collecting data on how much total storage has been allocated to each system, how much of that is actually in use, and how often the data is accessed or changed. This information is critical in defining your current environment so that you will be able to plan for the future based on hard facts instead of just guesses.
The better SRM tools can also automate some of the more common tasks that storage administrators typically handle, such as archiving old and/or unused data, finding and deleting games and MP3 files, and watching for, alerting on, and automatically expanding file systems that are filling up. Some SRM vendors even offer monetary guarantees that customers will improve storage utilization by significant percentages.
Storage area network (SAN) management tools (the subject of the third article in this series) can help you to create visual, logical diagrams of switches, storage devices, bridges, host bus adapters (HBAs), and other devices in your SAN. The better tools are also capable of monitoring the environment, with threshold-based alerting for errors, link capacities, and switch capacities. Some of these tools also enable a "single pane of glass" management screen from which you can perform all SAN management tasks, from adding new zones and changing existing zones to provisioning storage.
The fourth article will discuss storage virtualization, which is software that essentially tricks servers into seeing blocks of storage that are assembled together somewhere else as physical disks. This capability has existed for many years in volume management software, and in a different form on disk array controllers (although it wasn't always called virtualization). These arrays present virtual devices to attached systems that are related to the physical disks the data is stored on, but this relationship is not apparent to the host system. The server using storage from the array thinks that it is seeing individual disks, or LUNs, while inside the array the LUNs are really stripes or mirrors with data layered across several physical disks. The server has no reason to know where the data is actually stored, just that it is always accessible and responds to I/O requests reliably and quickly.
Newer storage virtualization "appliances" serve essentially the same virtualization function as array controllers, disguising the true location and physical form of the storage devices where data is stored, and presenting it in a simpler form to the servers.
These appliances also allow storage to be provisioned through a single management interface, while allowing the data to physically be stored on, migrated between, and replicated from one storage device to another. All of these changes to physical locations and copies of data can take place while the server remains online and is accessing data from its "virtual" disk devices.
The last article in the series will focus on interoperability between the various types of storage management software tools, which is critical to getting the most use out of them.
Whether interoperability comes in the form of data exports and imports, common databases, common interfaces, etc., the more closely the tools work together, the better they will all be able to help you save money and get better control over your storage, budget, and time.
A little history
During the 1990s, capacities grew explosively, as did the storage portion of many IT budgets. If you needed more space (and you always did), the easiest way to get it was to just buy more disks. Direct-attached storage was everywhere, often with capacity utilization at less than 50%. Little effort was made to improve efficiency and manageability, due in part to rapidly declining storage prices.
Inefficient use of storage and staffing resources was rampant. It was cheaper to add personnel and capacity rather than focus on increasing storage utilization and improving management efficiency. Sharing storage between servers was often not even possible because so much of it was direct-attached. Shared storage was often poorly understood, poorly managed, and inefficiently used. There were no good SRM, virtualization, or SAN management tools available, especially for heterogeneous environments.
In the past few years, the changing economics of the business environment has forced companies to become more efficient. Budgets have been squeezed, and often one of the first places to see cuts is the IT organization. IT staffs have been forced to get by on less and to become more proficient at getting the most out of both their capital and labor budgets. Administrators who were once responsible for 1 to 2TB must now manage far greater capacities, usually in a much more complex infrastructure.
Fortunately, vendors have been working to come up with products to meet these new needs. A variety of vendors offer excellent products aimed at various segments of the storage management landscape, sometimes at acceptable prices. These tools enable a number of potential benefits: cut staff, improve response times, fulfill requests sooner, and improve storage utilization; more-efficient use of existing storage resources; better planning for future requirements; and save time and money, while enhancing utilization, efficiency, and maybe even performance.
However, one big question remains: Is it worth it to buy these products (which can be very expensive), and should you buy them now? For some IT organizations, particularly smaller shops, the answer may be, "No, not yet." For others, it is a resounding "Yes." As storage capacities continue to expand and storage networks become more complex, automation will become increasingly important. Automated storage management software can save large organizations far more money than would be spent on acquisition and installation of the software, meanwhile freeing up staff from mundane daily operations.
SRM, SAN management, and storage virtualization tools each has a place in large storage environments. If you haven't already implemented some of these tools, or at least started to look at how they might benefit you, you should get started.
Storage management products are likely to keep increasing in quality and interoperability, while declining in price. Despite this fact, it is not always a good idea to wait. The price of a particular product may decrease from, say, $100,000 to $75,000 during the course of a year. However, during that same time, several enhancements may be added to the software, so delaying your purchase gets you a better product at a better price. Let's say that the savings for buying this product a year later is $25,000. But how much did it cost you to save that $25,000? Did you have to hire an extra administrator or two, upgrade arrays, or buy new arrays or switches that you might not have needed? Did you have to forgo or delay the implementation of a chargeback system or other projects that would have saved you additional time and money?
If you don't have these tools in place now, start looking at them to determine if they would benefit you. Then figure out how, when, and at what price the benefits would outweigh the costs.
David Czech is a storage systems engineer with Xcel Energy, under contract through Distributed Office Environments, in Denver, CO. He can be contacted at firstname.lastname@example.org.