JBOD RAID Data Recovery

The acronym RAID stands for Redundant Arrays of Independent Disks. This is a technology developed to increase performance, security and storage capacity in environments involving servers and storage On Premise, Data Centers and Cloud Infrastructure. The technology in question began to be developed by researchers at the University of Berkeley (California, USA) in the mid-1980s. Such technology is based on the synchronisation of several disks, be they SATA, SSHD, Nearline, SAS and FC [Fibre Channel], to form one or more logical disks viewed by both the RAID controller and the operating system chosen to use the logical volume. The implementation of RAID systems combined with virtualization systems, scalable storage containing different technologies such as All Flash Storage and a high-speed Internet, enabled the creation of IT departments On Premise, Data Centers and the much talked about Cloud Computing, which allocate critical applications for business, such as large ERPs like TOTVS, SAP and others. There are several types of RAID and the most used respectively are RAID 5, RAID 1, RAID 10, RAID 6 and RAID 0.

In the vast majority of cases yes, it is perfectly possible to recover data in a complete and structured way, including Digital Recovery is a company specializing in data recovery in all types of RAID systems, regardless of the operating system and hardware that the logical grouping of disks is tied. No matter the size of your company or how complex the structure of your servers and storage is. Our professionals, with international experience, will be able to solve your problem with mastery. For your peace of mind, confidence and security, we suggest viewing our updated client list, testimonials and certificates of technical capability provided by federal agencies that have already been successfully assisted in projects involving RAID systems.

The most common situations that cause data to become inaccessible and RAID data loss to occur are:

Physical damage that occurred on the RAID controller
Physical damage to the server’s system board
Improper configuration changes to the RAID controller
Problems encountered on one or more disks at the same time
Problems booting the operating system
Loss of disk sequential order
Data corruption on GPT or MBR partitions
Problems occurring in the Rebuild attempts of one or more disks with problems
Improper recreation of both the RAID and the logical volume attached to the array
Problems experienced during an increase capacity process
RAID was rebuilt or rebooted with a different configuration.

The structure of RAID systems is based on three major differentials. (1) Security (2) Performance and (3) Increased capacity of dedicated devices for data storage. The RAID controller is hardware specifically designed for processing information from the volumes and partitions of an array. The controller card has, among others, two main functions: The first of them is to perform all the calculations regarding the data processing and storage of the parity information in the arrays. The second function is to store the configuration data of the arrays created and managed by the controller itself. A common technique used by the controllers to protect themselves of problems, is to store the data of the managed arrays in reserved areas in the own disks that it uses to create the arrays. This way, if a controller presents problems, a new controller can be installed and then execute the necessary commands to read the configuration data stored in the disks of the array avoiding data loss. Normally this region of the disk is known as the DACStore. If in fact the problem is in the controller, because of the protections previously reported, it is very likely that the environment will return to work normally. However, if there is a problem with the information recorded on the disks, the data will remain inaccessible.

We understand the disruption and damage a RAID server and storage outage can cause your business. With that in mind, we have created a 24×7 department that is dedicated to assisting customers who have extreme urgency in recovering data from RAID systems.

As soon as disks from a RAID server or storage enter our lab, the advanced diagnostic process begins immediately. The advanced diagnostic process usually takes between 4 to 8 hours. As soon as it is concluded, the customer will be informed about the possibilities of data recovery, the amounts involved, as well as the estimated time for recovery.

The average time for data recovery in servers and RAID storage at Digital Recovery is approximately 36 hours, but in some cases, projects have been solved in less than 12 hours. Depending on the complexity of the problem and the type of solution to be adopted, the time for data recovery may extend for a few days, but at all times a specialist will be in contact with the focal point of the customer, to report in detail on all movements made.

Regardless of the number of disks that will be allocated in the array, the system will use the space equivalent to one disk for parity, ie to get the net space, just multiply the capacity of the disks by the number of disks subtracting one.

Example | Considering 5 disks of 3 TB each, totaling 15 TB of raw space.

Subtracting one disk we have a total of 4 disks of 3 TB, ie, 3 TB x 4 = 12 TB

Certainly it is possible, as there are techniques available to reverse this type of scenario, as in most projects, we can safely change the disk status from defunct to online, in order to clone in isolation as soon as possible, the sectors attached to this problematic disk.

A Degraded RAID is when one or more redundancy disks have stopped working. Depending on the type of Array this will imply loss of performance. The surest way to know if the RAID is degraded is by accessing the controller management software. On IBM/Lenovo servers this software is called MegaRAID Storage Manager. Another way to see it is to observe if any orange led is lit on the disks belonging to the array in question.

The first action to be taken is to contact the manufacturer or technical support of your server or storage. They will direct the diagnosis in the best possible way, because through the logs collected, it will be possible to create a coherent and assertive action plan. If it is not possible to re-establish the environment either via the manufacturer or via restore the most updated backup, we can help you solve this challenge in the best possible way.

Because of the many variables involved in a RAID data recovery project, it is not possible to know the final value without performing a detailed evaluation. The purpose of this assessment is to determine:

Level of complexity and urgency
Real possibility of recovery
Time to perform the service
To perform an assessment, please contact us through our support channels, which are available 24x7x365.

Yes, in many situations it is possible to recover data from a RAID server or storage remotely. For more information about this recovery modality, please contact us through our support channels, which are available 24x7x365.

The Logical Volume Manager (LVM) can be fully recovered as it is an option for managing logical volumes of a hard disk or RAID in Linux/Unix operating environments.

We have compiled a list based on our many years of experience working with data recovery on RAID systems. Before you perform any procedure to attempt to recover data from your RAID system internally, consider these considerations:

Be confident that the procedures to be performed will not make the situation worse than it already is.
In most cases, attempts by technicians who do not specialize in RAID systems further complicate the data recovery process. Eventually, some of these attempts may make the data recovery process impossible.
Verify that the Backup is up to date. If you do not have a backup, before performing any procedure, the best thing to do is to seek specialized help.
Be careful with the Rebuild procedure.
Never execute the Initialize command. This seemingly harmless command (initialize) will completely reset all data on the RAID, thus making data recovery completely impossible.

A RAID 1 system is a type of RAID with 100% redundancy. This means that all information on one disk is mirrored or written to another disk. Even when using two disks, only a volume equivalent to one disk will be presented to the operating system. Whenever the user makes any change to the volume the system responsible for managing RAID 1, (either by software or hardware) will automatically replicate this change on both disks. Once I have 2 mirrored disks and exactly equal what are the possibilities of data loss? Although there is the possibility of simultaneous failure of the two disks, this possibility is very small. Most data losses on RAID 1 that we receive for recovery come from RAID management failures. See the following situations:

After 2 years of continuous use of a RAID 1, one of the disks fails with bad block issues. Because this disk is no longer in normal use, the controller or the array management software will discard any attempt to write or read to this disk. The system will also warn the user about the problem so that he can replace the failed disk quickly. This is exactly where most of the problems occur. Because the system continues working normally, because one of the disks is still 100% functional, the user does not pay attention to the warning and continues using the machine. Six months later, the second disk fails. But this time instead of only presenting failures caused by bad blocks the RAID disk is completely inaccessible. When trying to solve the problem connecting the disks on another computer or sending to a service the only disk that will still be accessible is the disk that stopped first (6 months ago), because even presenting bad blocks may still be possible to access some information, but, 6 months ago.
Because much of RAID 1 are mounted on common machines and without the infrastructure (Enclosure and RAID Controller) necessary for RAID systems, they are much more susceptible to failure. Because of this, another problem can happen when one of the disks presents problems in the cable or connection to the motherboard. Although the disks are without any problems, a bad contact in the connection cable of one of them interrupts communication. The Array management system warns the user, but he does not notice. As there is 100% redundancy of the data on another disk, the machine will continue working normally and without performance problems. Some time later, when doing maintenance on the computer, the cables are disconnected and reorganised. In this maintenance there is the risk of reconnecting the HDs in different ports and confusing the system. Once two disks are connected in RAID 1 again the system will identify that they are not equal, because there is enough time that one of them was disconnected from the RAID. At this point the system will update the information from one disk on the other. As the disks were connected on different ports, the system can simply copy the disk with old information on the disk with new information.
Following the same line of problems mentioned above, when one of the disks of RAID 1 fails and the user continues to use the system, there is the possibility of data loss if for some reason the user recreate the array. By doing so, the system will identify that the disks contents are not exactly equal. At this time the system will copy the information from the first disk to the second and data overlapping may occur.

In some cases yes. Especially when you have an environment with few disks and when you remember exactly the array configurations. But when you have storage with numerous hard disks, running with multiple volumes, using different RAID configurations and even with Hot Spare disks, even if you have all this documented will not be an easy task to recreate the Array and it will work again. In the case of Virtualized RAIDs or vRAID even having all the configurations noted the only possibility of returning the Array is by reading the settings contained on disks (DAC Store).

As we know that a disk failure can drastically impact both the availability and integrity of companies’ strategic data, 24×7 monitoring of the health status of disks is extremely important, as it allows the suspect disk to be replaced even before it actually fails. The RAID controller management software itself can be used for this type of predictive monitoring.