If your organization requires high availability and 24/7/365 uptime from its servers, creating a data storage system that uses hot-swappable Redundant Array of Inexpensive Disks (RAID) technology may be your best option to safely back up and restore your data with little or no downtime. Hot-swap RAID disks allow you to replace a faulty disk without turning off the system. In this article, we’ll take a look at hot-swap RAID and how it can benefit your organization.

Which RAID level works best for hot-swapping?
If you’re interested in using hot-swapping in a RAID configuration, your best option is to use RAID Level 1 architecture, also know as “disk mirroring.” With RAID 1, all of the server data is mirrored onto multiple disks. This removes a single fail point so that a disk malfunction will essentially have no effect on the system if the proper fail-over software is in place and operating correctly.

If there were a disk failure, you would simply remove the defective disk from the server and replace it with a new disk. In the meantime, the server would experience no downtime, and the users should not notice much difference in performance.

What drives work with hot-swapping?
Most newer IDE and SCSI hard disks support hot-swapping. Your hardware vendor can tell you whether particular disks are hot-swap and RAID friendly. The following vendors support hot-swapping:

In practice, most RAID configurations utilize SCSI disks. Most of the time you will purchase hot-swap RAID arrays as a complete package from a hardware or server vendor. Then you simply integrate this as a storage solution for your operating system.

What operating systems support RAID and hot swapping?
Currently, most major operating systems support hot-swappable hard disks. Below is a list of server operating systems that support hot-swap RAID configurations:

  • Windows 2000 Server
  • Windows 2000 Advanced Server
  • Windows 2000 Datacenter
  • Windows NT Server 4.0
  • Solaris
  • HP-UX
  • AIX
  • Most other UNIX operating systems
  • Caldera Linux
  • Red Hat Linux
  • Mandrake Linux
  • Most other recent Linux operating systems

If your operating system isn’t listed, contact the vendor of the OS to see if it supports hot-swap RAID.

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It’s also important to note that hot-swap RAID is a “hardware RAID” solution and is very different from the “software RAID” options you can utilize with built-in utilities in operating systems such as Windows NT 4.0, Windows 2000, and Red Hat Linux. A hardware RAID is the only option if you want to take advantage of hot-swapping because it relies on a piece of hardware called a hot-swap backplace that makes hot-swapping possible.

Bottom line
Utilizing hot-swap hard disks helps maintain uptime and availability for your company’s servers. One of the best parts of hot-swap RAID is the speed and efficiency of the work involved. Not only can your critical data continue to be saved to a system if a hard disk fails, but there is no downtime associated with the replacement of the affected disks. While this technology may cost more up front, the savings from avoiding downtime the first time you have a disk failure should easily offset the initial expense.

Are you considering using hot-swap RAID drives?

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