Have you encountered capacity issues with CD-ROM servers? Is your network growing so fast you’re running out of room for all the server boxes? I’ve used CD-ROM servers for years to host numerous research applications at my company. In the beginning, I purchased a CD-ROM server I thought would fit my company’s needs for a long time. I ran out of space two years after the implementation, as workgroups added more applications. I then purchased an additional server that could hold up to 28 CD-ROMs. With a total of 35 discs mounted on the network at any given time, I expected this set of resources would satisfy their needs. However, in another two years, I would reach capacity once again. I evaluated several ideas, but none fit my needs as well as network attached storage (NAS).

An expensive alternative
My company was unwilling to spend the money to purchase a high-capacity CD-ROM server. I found that running a CD from disk—i.e., copying the disc to a network drive and running it from there—enabled better performance than a CD-ROM server.

The idea of hosting the discs on the server sounded great. However, I felt uncomfortable allocating 600 MB of file server drive space for each CD-ROM disc. Situations such as RAID configurations, online spare drives, the cost of the network operating system, and high-end SCSI controllers can send the cost of hosting simple applications very high. Colleagues had offered solutions like putting up a Linux server with a huge hard drive. However, I didn’t want to add additional layers of complexity to a network with a new OS.

NAS to the rescue
After considering all the alternatives, I decided to host the discs on a NAS device. I found this model worked better because:

  • The NAS devices are more stable compared to a “white-box” or Linux server.
  • The $:GB ratio (see note below) was between $9 and $20 (prices varied between NAS devices with RAID and those without).
  • NAS devices can be configured for fault tolerance.
  • NAS devices can connect directly to a Windows NT/2000 network for rights and securities.
  • Connectivity is easy.
  • Backup strategy was not affected (as long as only CD-ROM disc contents occupy the NAS device).
  • NAS devices take up less space than a CD-ROM server.

I use a term called “dollar to gigabyte ratio,” expressed as $:GB. It simply reflects the price of a gigabyte of storage in a specified configuration. This ratio can be used in many applications when configuring storage options. Figure A shows the calculation of the ratio. Performance on a NAS device may be slower than on a high-end file server, but that minor sacrifice in speed was worth the approximately 66 percent savings per gigabyte.

Figure A
Calculating the dollar to gigabyte ratio

Setting a standard within the organization
The appliance model is a good choice because it can help control costs and make for smoother upgrades. Although a CD-ROM server is also considered an appliance, its span of functionality is smaller than that of a NAS device. As DVD media will eventually become a standard for software, I think this strategy will offer a more robust solution. After all, size and scalability do matter in planning decisions for your infrastructure.
If you’d like to share your opinion, start a discussion below or send the editor an e-mail.