A system crash, lost or destroyed files, and network failures can be disastrous for your business. Losing months or years of data can put you out of business. Most business owners know that they must back up their vital information, but unless it is readily recoverable, you’re setting yourself up for trouble.
Data backup can’t always restore all of your IT system’s data and settings. You may need a more robust form of disaster recovery because certain things like active directory servers and computer clusters may not be fully reconstructed. That’s why having a reliable backup plan via the cloud is crucial.
An enterprise-based cloud backup solution safeguards your data, so you can restore it, and continue working under any circumstance. The best enterprise cloud backup services can deliver complete backup, and disaster recovery capability for a multi-platform server environment with data sizes up to 100TB and beyond. And it can archive your local system as well as mobile devices, allowing them to be recovered fully automatically.
Properly restoring backups involves organization and expertise—It’s a complicated process. Most of us know that we must back up our data regularly. But using the wrong type of backup is just as bad as not backing up at all. The most reliable methods are backups to a secure offsite data center, a cloud-based storage solution, or a hosted cloud.
Properly Restoring Backup Options
A Quick Lesson About Backups
The Recovery Point
The goal of a backup is to get to the recovery point. A recovery point objective (RPO) is the data in backup storage required to resume normal operations if your computer system or network fails. Recovery time objective (RTO) is the maximum desired length of time allowed between an unexpected failure and the resuming of normal operations.
With a full recovery, you can specify the recovery point at a point in time, a marked transaction, or a log sequence number. The RPO and RTO help system administrators determine disaster recovery policies and procedures. They use them to decide which backup and recovery technologies to employ.
A differential backup is a procedure that records the changes in data that occurred since the last complete backup. A differential backup saves the new data or data that has changed since the last full backup; it doesn’t backup the same data every time.
Differential backups are preferred when you want to spend less time restoring your data. It involves less storage drive space than incremental backups, and the backup can complete more quickly than full or incremental backups. However, occasionally a full backup must be completed, or the differential backup can grow to a larger size than a full backup.
The philosophy of the incremental backup is that you can achieve data solvency by performing successive incremental backups after a full backup. It documents changes in shorter time periods.
An incremental backup also copies files that were added or changed. It copies the data that occurred since the last backup only, not the last full backup, as a differential backup does. The goal of performing an incremental backup is to document changes since the previous benchmark was established.
One of the primary benefits of the incremental backup is that it’s made against the original full backup but takes less time and effort to perform than doing a full backup. Incremental backups must be grouped together to have a comprehensive full backup.
Where differential backups back up any data against a previous full backup, incremental backups only back up data against any prior backup.
Data restore is the process of copying files from a backup to the original location, or to another required file location in order to enable correct database operations. For a proper data restore, all of the data must be from a specific backup date or restore point.
Every restore operation requires one or more restore steps. This is called a restore sequence. Data is copied from the backup and logged transactions are applied to the data to roll it forward to your target restore point. Logged transactions are a basic resource that provides information about network traffic. Rolling forward data (the redo) and bringing the database online is known as recovery.
Each backup must also contain sufficient logged data to roll back (the undo) uncommitted transactions, so the backup is stable and usable. Data logging facilitates the storage and collection of information.
The 3 Backup Phases
A restore involves a multi-stage process including the data copy, roll forward and roll back phases.
- Data Copy: This involves the copying data, logs, and index pages from the backup location to the database files. This is the first process to take place. It initializes the contents being restored. It involves copying data from one or more full backups and, optionally, differential backups.
- Redo Phase (Roll Forward): The roll forward (redo) applies logged transactions to the data copied from the backup to the recovery point to bring the data forward in time. It restores one or more full backups. If you specify particular files, only these items will be included. If not, all files in the backup will be included. If there are log records in the full backup, it will be used in the process. The oldest file or page determines the starting point for this phase. In the redo phase, data is always rolled forward to the point that is redo-consistent with the state of the database at the recovery point. This is where all the data has been rolled forward to a point at which an undo can occur. However, the database might contain changes made by transactions that are uncommitted at the recovery point. For online restore, data is recovered to a point in time that is consistent with the current state of the database.
- Undo Phase (Rollback): A rollback is a process of restoring a database to its previous state by cancelling a specific set of transactions. Rollbacks can be performed automatically by database systems or manually. When a user hasn’t saved a change, the data is stored in a transaction log. But, the user may decide not to save the data. In this case, a rollback command discards any changes without communicating this to the user. Rollbacks are also used after a server crash. When the database restarts, all logged transactions are reviewed, and pending transactions are rolled back so users can re-enter and save their changes. After the redo phase has rolled forward all the log transactions, a database typically contains changes that need to be rolled back. After the database is transactionally consistent, the database is brought online.