The Importance of Hardware RAID in Small and Medium Businesses
Redundant array of inexpensive disks (RAID) is used when a system needs higher storage reliability. Companies with 24/7 applications, mission critical processing or just in need of better disk throughput will look at RAID technology. When researching the options, one will be faced with a choice of software or hardware RAID.
Hardware versus Software RAID
Implementing RAID through software requires an application that will partition physical disks into virtual disks onto which the application will write data. The application runs on the same server as the operating system (OS) and will be using the same resources as all other processes running on that server.
Hardware RAID is a standalone unit, complete with its own power supply, cooling and its version of an OS with utilities. Software on the server communicates with the RAID unit when it’s time to write something and the RAID unit does the work. This removes the majority of the “data read and write” processing from the server.
Resource Use is Minimized with Hardware RAID
Because hardware RAID is separate from the server, it doesn’t use valuable CPU, memory or cache. Software RAID competes for all of these resources. The server passes data through a high-speed interconnect to the hardware RAID unit and then checks for a “write complete” message or data returned from a read request. Hardware RAID has minimal impact on the server resources.
Server Speed is Enhanced with Hardware RAID
Because the server does not need to process read/write requests when using hardware RAID, its resources are free for other activity. Software RAID can tie up processing and slow down servers. Trying to do anything more sophisticated than RAID0 or RAID1 with software will slow down the server appreciably. Regardless of the RAID level implemented, the hardware RAID unit takes care of the processing with little impact on the server speed. To the users, the server performs faster with hardware RAID.
Better Data Protection with Hardware RAID
If the system should fail while using software RAID, there is a risk that the I/O was not completed, or worse, corrupted. With hardware RAID, the unit will complete the I/O even after the failed server has shut down. It uses write back caching (if battery backup is implemented) to make sure that the data write is completed. Software RAID cannot make use of a backup battery and any caching it may do will impact the server performance even more.
If you have a disk failure with software RAID, there will be some downtime while the disks are swapped and synced up. Most hardware RAID units allow hot-swapping. This lets you remove a disk from use while the server is still running, physically replace it with another, and sync up the disks without affecting the server activity.
Another important capability is having a hot spare. This is a physical disk in the hardware RAID unit that is designated as a backup so it is not written to during normal operations. Should another disk fail, the RAID unit will switch to writing to the hot spare, sync it up with the other disks and rebuild the array automatically. Businesses that rely on 24/7 operations benefit from hardware RAID availability and protection.
How Advatronix® Can Help
We offer an advanced server solution that will keep your data intact with our highly customizable hardware RAID solution that comes with the Cirrus™ 1200.