![]() Backup of course involves copying data to some secondary storage device. And since as we describe above, most data should not be replicated, it is the primary recovery method for most data sets. When to Use Backup?īackup should be applied to all data, including data being snapshotted and replicated. Doing so reduces the capacity requirements of the second or third system. IT professionals should use care to make sure only data and applications needing very fast recovery and minimal data loss be assigned to the replication process. The challenge with replication, of course, is the expense required to buy a second or even third storage array. ![]() As a result replication tools are able to survive not only a media failure but also a storage system failure. The difference is when a data segment changes the blocks representing that change are replicated to another storage system or another site, instead of, or in addition to, being tracked on the same system. ![]() They use the same block tracking as snapshots. Most modern replication tools leverage snapshots. As a result snapshots are excellent for quick recoveries from data corruption or accidental deletion, since the old catalog can be promoted to replace the current one. It is totally dependent on the media being intact in order for it to work. Modern storage systems can maintain hundreds of snapshots with minimal performance loss.Ī snapshot is the opposite of RAID. The storage system creates new entries in the catalog for new or changed data blocks but preserves the old catalog, which results in a point-in-time view of the snapshotted data. When a user or application requests data, it in reality is making a request of the catalog which then points the request to the actual data.Ī snapshot makes a copy of the catalog or a section of the catalog and then sets all the data that is it mapped to read only. Most arrays create a catalog that maps to the actual location of data that it stores. ![]() Snapshot technology takes advantage of the way the arrays organize data. This is a protection mechanism that is built into most modern storage systems. After a snapshot is taken, the snapshot system preserves the view of that point in time by preserving any blocks that change after that point. A snapshot is a virtual view of a volume or file system from a particular point in time. The next type of data protection that most organizations have at their disposal is snapshots. My colleague, Joseph Ortiz, provides a detailed look at RAID and its various levels in his “ What is RAID?” blog series. RAID 3 through RAID 6 as well its parity based derivatives alleviates this concern and reduces the media protection overhead by as much as 75%. Mirroring brings a high level of redundancy at a high cost, an effective doubling of capacity requirements. The problem is the earliest form of media protection was mirroring, which makes a real-time copy of data on a separate drive, known as RAID 1. Some type of protection from media failure is an absolute requirement. While most organizations have access to RAID, replication and snapshots, most do not have a formal plan in writing on when to use which tool and under what circumstance. And each of those data protection tools help the IT professional recover from different types of data loss events. There are varying degrees of data protection offered as features of RAID, backup, replication and snapshots. "": "inventory.“Backups.” It’s the universal term used to describe a much broader set of tools that make up the entire data protection process. "": "inventory.customers,inventory.dbz_signal", # Start Postgres connector, capture only customers table and enable signallingĬurl -i -X POST -H "Accept:application/json" -H "Content-Type:application/json" -d <<EOF Docker-compose -f docker-compose-postgres.yaml upĮcho "CREATE TABLE inventory.dbz_signal (id varchar(64), type varchar(32), data varchar(2048))" | docker-compose -f docker-compose-postgres.yaml exec -T postgres env PGOPTIONS="-search_path=inventory" bash -c "psql -U $POSTGRES_USER postgres"
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