Shadowbase Zero Data Loss (ZDL)

Net catching data streamIn today’s business world, consistent access to real-time, online transactional data is a competitive advantage. To realize this advantage, this data must be current and available across the enterprise at all times. Otherwise, the inability to access or update, or the loss of this data carries significant potential business cost: up to thousands of dollars per second loss of brand reputation, regulatory fines, and other unforeseen consequences that could be prevented.

Diagram of average costs of downtime (please see "Figure 1 states" sentence for full description)

Figure 1 — Average Costs per Hour of Downtime Across Various Industries

Figure 1 states the numerous costs per hour of downtime by industry (in USD): healthcare loses $636K, retail $1.1M, financial $1.5M, manufacturing $1.6M, and Communications/Media/Entertainment $2M, with the average at $1.4M.

(Source: Network Computing, the Meta Group, Contingency Planning Research.)

In some cases, absolutely no data loss can be tolerated:

  • Healthcare – Lost dosage records can result in patient overdose or underdose on medication.
  • Manufacturing – Car manufacturers can tolerate short production line outages, but cannot lose data regarding bolt torque settings, in case of lawsuits from accidents.
  • Electronic Funds Transfer (EFT) – Some transactions are worth millions, even if the average transaction is much lower.
  • Stock Trades – Competitive data and stock price is based on previous trades, so none can be lost.
Table 1 — Estimated Cost of Lost Data Across Various Industries in USD (i.e., 500 transactions per second)
Technology Architecture Recovery Point Objective Retail Credit/Debit Card EFT Stock Trade
Active/Passive and Sizzling-Hot-Takeover5 ~1 sec $47.5K $35.6K $688K $31.6M
Active/Active ~0.5 sec $23.8K $17.8K $344K $15.8M
Average Transaction Value N/A ~$95
1Source: Monetate
2Source: European Central Bank
3Source: Canadian Payments Association
4Source: London Stock Exchange
5Asynchronous replication

The Solution

Most other data replication software uses asynchronous replication that leads to the possibility of data loss for unplanned outages. For this reason, companies must consider a zero data loss solution to protect their invaluable data. Shadowbase ZDL guarantees that all committed data changes made on one system are replicated to a backup system. Therefore, unplanned system outages never result in lost data, and the business will never face these costs or the headache of trying to recover lost data.

Shadowbase ZDL uses synchronous replication, which avoids data loss for active/passive architectures, and eliminates all possibility of data loss, as explained in these definitions:

Asynchronous Replication

  • The application’s database changes are not synchronized with the replication activity.
  • After the application makes data changes, the replication engine reads those changes, and delivers and applies them to the backup database.
  • During a failure, data changes committed on the source may not have been delivered or applied to the backup database, and this data is at risk and may be lost.

Synchronous Replication

  • Replication activity is synchronized (coordinated) with the application that is making database changes on the source.
  • Source database changes are safe-stored and/or applied to the backup database, before the application changes are committed.
  • Therefore, there cannot be updates committed on the source, which have not been saved on the backup, eliminating any possibility of data loss. No committed data is ever at risk, regardless of what happens at or to the source environment.

Shadowbase ZDL+ Automatically Resolves Data Collisions (Future Release)

Shadowbase ZDL support for active/active architectures is called Shadowbase ZDL+ and will be available in a future release. In active/active architectures, data collisions can occur when using asynchronous replication. By their very nature, active/active architectures run multiple application copies, with each application maintaining its own database copy. If two requests are routed to different application environments for processing, and they both act on the same account’s data, different values may result in each database. This result is referred to as a data collision. Data collisions cannot arise when using synchronous replication because the replication engine automatically resolves them.

Table 2 compares the benefits of synchronous replication (Shadowbase ZDL and the future Shadowbase ZDL+) to asynchronous replication.

Table 2 — The Benefits of Synchronous Replication by Replication Mode
Attribute Asynchronous Active/Passive Synchronous Active/Passive Asynchronous Sizzling-Hot-Takeover Synchronous Sizzling-Hot-Takeover Asynchronous Active/Active Synchronous Active/Active
Failover Faults Yes Yes No No No No
Backup Utilized No3 No3 No No Yes Yes
Data Collisions Not possible Not possible Not possible Not possible Possible Not possible
Data/Request Partitioning Not required2 Not required2 Not required Not required Possible Not possible
Application Outage Yes Yes Minimal1 Minimal1 No No
Data Loss Yes None Yes None Yes None
1All users affected, but takeover time is the same as Active/Active modes
2“Required” if run in Reciprocal Mode (Reciprocal Mode allows each system to be active for a separate data set)
3“Yes” if run Reciprocal Mode

Use Shadowbase ZDL to significantly reduce outage costs by avoiding any data loss, eliminating data collisions, and applying active/active architecture benefits to any application. Shadowbase ZDL is the pinnacle of replication solutions for business continuity and data integration, providing the ultimate protection level against unplanned service outage costs.

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