Redundant Array of Inexpensive Devices
Most often found in upper end servers and some NAS (Network Attached Storage) devices. These types of storage have amazing abilities to protect your data, make it accessible to your entire network, and provide increased performance. They can also become a giant mess when you have a drive or multiple drives fail.
Some server storage enclosures have anywhere from 3 to 12 drive slots. When a drive goes offline it can be difficult to isolate which drive that really is and where in the enclosure it is sitting. Some enclosures have miniscule LED’s that are supposed to communicate trouble, some have LCD screens, others have only alarms. So, why does knowing which drive has failed matter so much? It is a RAID right? They are built to recover from failures, you can just pull a drive or two out and replace them, right?
Not so fast! Knowing which drive has failed is important. If you have multiple failures, knowing which went offline first is VERY important. Imagine this scenario… Two doctors begin practicing medicine at the same time. One doctor changes professions after 2 years and the other practices for 10 years. If you were given the choice of getting care from one of those 2 doctors, you’d want to know which one had been in practice most recently. If you tried to get care from the doctor who retired after 2 years, his practical knowledge would be out of date. Plugging him back into a client room could cause mass confusion.
Replacing a hard drive in an array is similar. Trying to rebuild your array with a drive that has been offline for days, weeks or months can RUIN the rest of your good data. Rebuild with the good drive and and you are back up and running.
Moral of the story… Make sure you know which drive is which in your array, determine which drive had gone offline first and if you are sure of any part of this equation – call in a data recovery expert!