As data volumes increase,
conventional
backups are taking longer to complete --
often disrupting normal production time by running beyond the
evenings and weekends typically set aside for backups. Beyond
the burgeoning demands of time, businesses seek smaller recovery
point objectives (RPO) and shorter recovery time objectives
(RTO). While "point-in-time" schemes, like
snapshots, are helping to manage this time
crunch, busy IT organizations are employing
continuous data protection (CDP)
technologies to guard data on the fly, essentially eliminating
the backup window and allowing granular file and system
restoration -- sometimes down to the individual disk write
operation. Several CDP appliances are available, but many are
implemented in software, and all require careful consideration
before purchase. Now that you've reviewed the
essential issues involved in any backup
acquisition, this section of the Guide focuses on the
specific considerations for CDP products. You'll also find a
series of specifications to help make on-the-spot product
comparisons between vendors, like Asempra Technologies Inc.,
CA., FilesX Inc., Revivio Inc., Symantec Corp. and more.
@31115 CDP may not be appropriate in every situation. CDP
technology is best deployed to protect a limited number of
applications in highly transactional environments with a distinct
need for minimal backup windows and recovery points. If backup and
recovery needs are currently being met with more established
technologies, like snapshots and replication (even tape), companies
often opt to forego the expense and added management overhead of
CDP.
Consider the supported application(s). Although some CDP
products can offer "general-purpose" coverage in the environment,
most products are typically deployed to protect specific
applications, like Exchange or Oracle. For example, Atempo's
LiveServ is intended specifically for Microsoft Exchange. It's
important to understand the applications that CDP will protect, and
then select a suitable CDP product.
Consider software vs. hardware deployment. CDP
appliances, such as Revivio's CPS 1200, are basically CDP servers
with software and storage that are packaged for quick deployment.
In most cases, CDP is purchased as software that is installed on an
available server in the enterprise, using the server's storage or
other storage in the data center (a.k.a. "host-based"). Both
approaches will generally yield the same result. However,
software-based CDP is less expensive to acquire, but installations
often require more time and technical expertise than hardware-based
appliances. Remember that CDP may require anywhere from 5% to 40%
more space for journal storage, so an application with 100
terabytes TB of storage may need another 5 TB to 40 TB for CDP
journaling. This may require a storage upgrade to provide adequate
storage for the CDP platform.
Evaluate the impact of CDP on the production network.
Data must be passed from the application(s) to the CDP product, and
this additional traffic will demand some amount of network
bandwidth. This can sometimes adversely
affect network performance. Performance is generally influenced
more with in-band CDP products that actually sit in the data
stream -- potentially forming a bottleneck to network traffic.
Out-of-band CDP products typically impose fewer traffic problems
but rely instead on
agents that can complicate application
server configurations and maintenance. Evaluate any CDP product
in advance to determine its impact on your service levels.
Consider security issues with CDP. Many CDP platforms
allow users to recover lost or corrupted files themselves. While
this can save substantial time and trouble for the storage
administrator, it does raise a serious question of data security.
Before implementing a CDP product, understand the security issues
involved in data access and restoration. Understand how recoveries
are authorized and secured to prevent theft or malicious abuse.
CDP is not a replacement backup technology. Analysts
agree that CDP addresses a specific data protection need and should
be considered as part of an overall data protection strategy -- CDP
should not replace established backup technologies, like snapshots
or tape backup, and it is typically used in conjunction with those
conventional tools.
The CDP product specifications page in this chapter covers the
following products:
- Asempra Technologies Inc.; Business Continuity Server
(BCS)
- Atempo Inc.; LiveBackup
- Atempo Inc.; LiveServ for Microsoft Exchange
- Availl Inc.; Availl Continuous Backup
- CA; XOsoft WANSync
- DataCore Software; Traveller CPR - Continuous Protection and
Recovery
- EMC Corp.; RecoverPoint software
- FilesX Inc.; XpressRestore for Mission Critical
Applications
- IBM; Tivoli Continuous Data Protection for Files
- Lucid8; DigiVault software
- Mendocino Software; InfiniView
- Microsoft Corp.; Data Protection Manager 2006
- Mimosa Systems Inc.; NearPoint for Microsoft Exchange
Server
- Peer Software; PeerSync Workstation for continuous Desktop and
Laptop protection
- Revivio Inc.; Continuous Protection System 1200
- SonicWALL, Inc.; CDP 1440i, 2440i, 3440i, 4440i
- Symantec Corp.; Backup Exec Continuous Protection
Server
- Symantec Corp.; Backup Exec Desktop and Laptop Option
(DLO)
- TimeSpring Software Corp.; TimeData Continuous Data Protection
Software
- Yosemite Technologies Inc.; Yosemite FileKeeper
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