24 Questions
What is the primary purpose of backing up data in a data warehouse?
To ensure data availability for recovery in the future
What type of backup involves shutting down the database?
Cold backup
What is the main advantage of partial backup?
It enables daily backups of parts of the database in a round-robin fashion
What factors affect the speed of processing backup and restore?
Hardware used, network bandwidth, server's I/O system, and backup software
What type of backup is similar to hot backup?
Online backup
What is the purpose of choosing the right hardware for backup?
To increase backup and restore speed
What is the primary difference between hot and cold backups?
Hot backup requires the database to be up, while cold backup requires it to be shut down
What is the main benefit of using complete backup?
It backs up the entire database at once
What is the capacity of DLT tape media?
40 GB
What is the primary function of a tape stacker?
To load multiple tapes into a single tape drive
What is a factor to consider when selecting a tape medium?
The reliability of the tape medium
How can standalone tape drives be connected to a server?
Directly to the server, as network available devices, or remotely to other machines
What is a challenge in connecting tape drives to a data warehouse?
Ensuring sufficient bandwidth is available during data transfer
What is the I/O rate of 8 mm tape media?
1 MB/s
What is a consideration when upgrading a tape system?
The cost of upgrades to the tape system
What is the capacity of 3490e tape media?
1.6 GB
What is a common feature among tape silos, disk backups, and optical jukeboxes?
The ability to perform unattended backups
What is the primary advantage of disk-to-disk backups?
Faster initial backups and restore
What is the purpose of mirror breaking?
To create a temporary backup while the primary database is online
What is a drawback of optical jukeboxes?
Slow write speed
What is the primary purpose of software backups?
To assist in the backup process
What is a characteristic of tape silos?
Ability to manage thousands of tapes
What is a benefit of disk-to-disk backups?
Online copy of the latest backup
What is a characteristic of optical media?
Long-life and reliability
Study Notes
Data Warehousing Backup
- A data warehouse is a complex system that requires a backup strategy to ensure data availability for recovery in the future.
- Backup terminologies:
- Complete backup: backs up the entire database at once, including all files, control files, and journal files.
- Partial backup: does not create a complete backup of the database, useful for large databases.
- Cold backup: taken when the database is completely shut down.
- Hot backup: taken when the database engine is up and running, with varying requirements depending on the RDBMS.
- Online backup: similar to hot backup.
Hardware Backup
- The choice of hardware affects the speed of processing backups and restores.
- Hardware options:
- Tape technology
- Disk backups
Tape Technology
- Tape media options:
- Capacity and I/O rates:
- DLT: 40 GB, 3 MB/s
- 3490e: 1.6 GB, 3 MB/s
- 8 mm: 14 GB, 1 MB/s
- Other factors to consider:
- Reliability of tape medium
- Cost of tape medium per unit
- Scalability
- Cost of upgrades to tape system
- Cost of tape medium per unit
- Shelf life of tape medium
- Capacity and I/O rates:
- Standalone tape drives:
- Can be connected directly to the server, as network available devices, or remotely to other machines.
- Issues with connecting tape drives to a data warehouse, including node selection and optimal performance.
- Tape stackers:
- Load multiple tapes into a single tape drive, allowing for unattended backups.
- Prices and capabilities vary.
- Tape silos:
- Provide large storage capacities, storing and managing thousands of tapes.
- Can integrate multiple tape drives, with software and hardware for labeling and storing tapes.
- Often connected remotely over a network or dedicated link.
Disk Backups
- Methods:
- Disk-to-disk backups
- Mirror breaking
- Used in OLTP systems to minimize database downtime and maximize availability.
- Disk-to-disk backups:
- Faster than tape backups
- Advantage of having an online copy of the latest backup
- Mirror breaking:
- Have disks mirrored for resilience during the working day.
- Break out one of the mirror sets for backup.
- May require database shutdown to ensure consistency.
Optical Jukeboxes
- Allow data to be stored near line.
- Manage a large number of optical disks like a tape stacker or tape silo.
- Drawback: slow write speed compared to disks.
- Advantages: long-life and reliability, making them suitable for archiving.
Software Backups
- Software tools are available to aid in the backup process.
- These tools come as a package.
Learn about the importance of backing up data in a data warehouse and designing a backup strategy. Understand complete backup, incremental backup, and other backup terminologies.
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