Nested RAIDs combine two or more RAID configuration levels for improved redundancy and speed. Common implementations include RAID 1+0 (also known as RAID 10) and RAID 1+5, both of which are popular for web servers, storage servers and other mission-critical systems.
When you implement a nested RAID system, you should immediately set up an appropriate backup system. RAID is not a substitute for good backup habits, and even if your RAID provides improved redundancy, logical issues can prevent you from accessing your data.
At Secure Data Recovery Services, we regularly work with all types of RAID systems including various nested RAID implementations. Here are a few tips for improving your chances of a successful recovery after a data loss disaster.
Why Nested RAID Devices Fail
RAID failure scenarios depend greatly on the array's level of redundancy. Most nested RAID configurations are designed to add media failure tolerance.
RAID 1+0 systems, for instance, can continue to operate after sustaining a number of hard drive failures. As such, hard drive failures rarely cause permanent data loss in these systems except in natural disasters and other catastrophic situations. However, a RAID 0+1 can sustain fewer failures in most implementations. If you have a system with limited failure tolerance, media failures are always a serious threat.
Controller damage accounts for a large percentage of nested RAID failures. When a controller stops functioning, it may cause parity issues that prevent normal data access. Failures can occur during rebuilds in some systems, causing extensive file corruption and logical damage.
User error is another major source of file loss. Secure Data Recovery Services regularly receives RAID systems with deleted or overwritten data, and to recover affected files, our engineers need to work with specialized utilities designed for various nested RAID implementations. Larger systems are also susceptible to virus attacks, which can cause significant damage in a matter of minutes.
Steps to Take After a Major Server Failure
Regardless of the source of media damage, the steps that you take immediately after your server failure will directly affect your chances of a successful recovery. For the best possible results, keep your system turned off. Do not attempt to rebuild a damaged array, as this can seriously complicate the data recovery process. Make a note of any symptoms that preceded the failure and contact a qualified data recovery provider as soon as possible.
RAID data recovery requires specialized tools and years of experience. Keep these tips in mind when looking for a qualified provider.
- Ask about Cleanrooms. Cleanroom technology allows data recovery companies to treat physically damaged media. If a provider does not have a certified Cleanroom, its engineers cannot safely treat hard drives or solid-state drives to restore your array to a functional condition.
- Look for certifications. Reputable data recovery providers offer access to their security certifications. Important credentials include SSAE 16 Type II certification, SAS 70 certification and any compliance regulations that apply to your business.
- Ask about experience. No two nested RAID systems are the same, but experienced engineers can create effective, individualized recovery plans to return your data in its original condition.
- Ask about turnaround options. Nested RAID systems usually hold mission-critical data, so turnaround time is an important factor to consider.
In our experience, most nested RAID arrays are completely recoverable if users shut down their systems immediately and make no attempt at recovery or repair. Nested RAID systems are complex and can present a number of unique challenges for engineers, but a qualified data recovery provider can quickly restore damaged files to a working condition.