Tech & Work

Ask these questions before spending cash for cache

Thinking of buying cache? Be sure to evaluate whether your needs can best be met by a cache appliance or cache software. Read the four questions you should answer before laying down the cash for cache.


If you need a fast way to speed up delivery of content inside your company or to customers, cache can help. But before you issue an RFP, you should determine which type of cache solution you’ll need.

While there are numerous cache vendors, you can basically divide the types of cache solutions into two categories: cache appliances and cache software.

Here are four questions to ask before you commit to a cache solution. They'll help you choose whether you need cache software, a cache appliance, or a satellite cache.
  1. What is your IT management philosophy?
  2. Is cost a big factor?
  3. Do you want an easy solution?
  4. What features do you need?
Unsure what cache does for your network speed? See our last article on the subject, “Is cache worth the cold, hard cash?”
What is your IT management philosophy?
How does your IT/IS division manage systems? Do you like to customize and manage, or do you need a low-maintenance solution?

“If your IS department is the kind that prefers hands-off management, then an appliance might be better,” advises Duane Wessels, a cache researcher and developer with IRCache, a program funded by grants from the National Science Foundation. ”If they would rather be more involved and be able to see what’s going on and have more control, then a software solution might be better.”

Joel Yaffe, a Giga Information Group analyst who researches cache, said it’s something of a philosophical choice.

“An appliance is something that’s very easy to set up and it’s very inflexible in terms of what you can do with it,” Yaffe said. “Software is more difficult to set up, but you can do whatever you want with it basically. You can develop around it, program-modify it, repurpose equipment to serve as the platform for running it.”

With software, you must have on-staff resources with the proficiencies to configure the software, he added.

Is cost a big factor?
Generally, you’ll pay more if you opt to purchase a cache appliance. Vendors contend that appliances will spare you the cost of purchasing additional servers. And cache appliances aren’t cheap; they can range from a few thousand dollars to more than $100,000.

Eric Stern, senior product developer for the cache vendor LogiSense Corp., said appliances are more effective and easier to maintain, but their costs deter some companies from purchasing them.

“Many companies would probably have a problem spending more than $2,000 just to speed up the Web, plus the trouble of having additional hardware on-site,” Stern stated. “This is where cache software comes in. If a company has a relatively small number of users, say, 100 to 500, and a Windows NT server that is not already overloaded, it is a relatively simple matter to install some caching software—our CacheXpress for NT, for example—on that NT server and have a useful cache running in a few minutes, for much less than an appliance would cost.”

Along the same lines, an inexpensive software package to consider is Squid, which is cache freeware for UNIX-based systems. Wessels develops Squid software and is currently developing a Windows NT-compatible version.

Do you want an easy solution?
But if you’re looking for an easy solution, Squid is probably not the answer.

Like much freeware, Squid can be buggy. It’s great for a small, technically savvy company, Wessels said. But if you’re a five-person company with limited technical skills and a DSL line, it will require administrative resources you probably don’t have.

“There’s a mailing list versus a tech support line you can call. There’s an FAQ on the Web instead of a manual that you get with a box,” he said. “You have to be comfortable with UNIX and installing software.”

With software, you must either configure your server or set up a separate box. That means you run the risk of spending too much on a fast CPU you don’t need or not installing enough memory, Wessels said.

With an appliance, the vendor handles the configuration.

Stern considers convenience one of two reasons to choose a cache appliance over software.

“You plug the device in, and it works [within] five to 10 minutes of configuration,” he said. “No further effort required. This can be very important for companies with busy IS departments.”

Giga’s criteria for selecting a cache that will work for your company.


Stern’s second reason for choosing cache appliances is the performance.

“Cache appliances are tuned for the caching application and hence can handle more traffic than your typical PC running caching software,” he said. “However, this really only becomes an issue when you have many users utilizing the cache, say, more than 1,000.”

Greg Govatus, director of marketing for CacheFlow, Inc., a cache appliance manufacturer, contends that appliances are optimized for caching and therefore more effective. Appliances also liberate your server to do other things.

After all, you wouldn’t use a server to do a router’s job, he said.

“Cache is built to live on the edges of the network and handle lots of connections, lots of transfers at a single time,” Govatus said. “It performs better, it’s more reliable in that the management relief is huge.”

What features do you need?
Like everything else, cache comes with options, and the more options, the more money you’ll spend.

For instance, cache can filter content and screen for viruses. A recent product from CacheFlow will even detect and stop Denial of Service attacks.

If security is your primary concern, give serious consideration to an appliance.

According to Yaffe, cache appliances run on proprietary operating systems that are already hardened, making them less vulnerable to an attack and thus providing you with an added layer of security. If you’re proficient in setting up your own hardware, you can set up your own cache to do the same thing.

Also consider whether you want to mix and match products or stick with one brand. According to Wessels, you can get cache to match your Windows NT or Solaris systems.

Scalability is something else you should consider before purchasing either type of cache. In fact, the price differences between cache appliances generally reflect the product’s scalability, according to Govatus. CacheFlow’s products, for example, range from $4,000 to $80,000.

“What’s interesting is the fact that we see a tremendous amount of growth at the high end of our product line,” he said. “Most of our customers actually build capacity to handle the peak and not just the norm.”

For more information about specific cache vendors, visit the Internet Caching Resource Center, which includes a vendor list, complete with product descriptions and links to each vendor's Web site.
Is cache something you’re considering? Tell us why or why not by e-mail or post below.

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