PCI-X Disk Controllers and RAID Cards: Easy Redundancy
While consumers can easily configure a RAID (redundant array of inexpensive drives) with a motherboard that supports it and with multiple disks, enterprise solutions like RAID 5 and 6 require additional hardware to attain stability and reliability. RAIDs 0, 1, and 10 are typically classified as consumer solutions, while RAIDs 5 and 6 are reserved for enterprise and business applications, which use SAS drives instead of consumer SATA drives.
What Are Some Configurations?
- 0: This type of setup prioritizes speed. It combines two drives or more and stripes the data across all of the SATA drives. This means you get n times the speed and capacity depending on the number of drives used but at the cost of reliability because if one drive fails you lose all the data in all the drives.
- 1: This emphasizes reliability. You get the capacity and performance of one of your drives but get the redundancy of two drives. If one of the two or more drives fail, you can still retrieve the data from the other drives.
- 10: This is a little bit of both worlds. This uses four drives, striping them in pairs and mirroring them with each other. You get double the performance and capacity of one drive while being able to lose two drives without data loss.
What Is a Disk Controller?
- RAID 5: RAID controllers like the LSI MegaRAID controllers are required for using this type of setup optimally. It needs at least three drives to operate with one drive reserved for rebuilding the data in the array if any hardware failure occurs. SAS drives can be used with these cards but are compatible with the SATA interface as well. The PCIe SAS 9271-8i is a controller that has two SAS interface connectors, which can take up to 32 SAS or SATA drives when used with splitter cables or adapters.
- RAID 6: This is like a more durable version of RAID 5 and uses four drives. Two drives can fail in the setup without losing data but is much slower to write than RAID 5; however, this can be compensated for by using a PCie MegaRAID controller built for this purpose.
What Other Accessories Can I Buy?
- Battery Backup: Data management devices are fragile so guarding against power loss is a must. Even if you have your LSI RAID configuration setup, this does not fully protect against data loss due to power outages. Get a battery backup so that you can finish your data transfer operations in time before properly shutting off the system or while waiting for a generator to kick in.
- More Drives: The adapters in devices like MegaRAID and other RAID controllers allow for easy expansion through adapters. This means that you can add multiple drives by purchasing more splitters for the RAID controller or scale your data with your business by populating the adapters, which do not have drives installed on them.