Shadowbase Zero Data Loss (ZDL) – Synchronous Replication

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.

Real-world Shadowbase Business Continuity Use Cases


Average Costs per Hour of Downtime Across Various Industries

Figure 1 — Average Costs per Hour of Downtime Across Various Industries
(Source: Network Computing, the Meta Group, Contingency Planning Research)

Figure 1 states the numerous costs per hour of downtime by industry (in USD) with an average of $1.4M.

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

  • Healthcare ($636K) – Lost dosage records can result in patient overdose or underdose on medication.
  • Retail ($1.1M) – Lost payment transactions may lead to a situation where sales disappear along with the inventory.
  • Electronic Funds Transfer (EFT) ($1.5M)– 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.
  • Manufacturing ($1.6M) – Car manufacturers can tolerate short production line outages, but cannot lose data regarding bolt torque settings, in case of lawsuits from accidents.
  • Communications, Media, and Entertainment (CME, $2M) – Lost EPs and music tracks could mean millions and may be completely unrecoverable

Table 1 — Estimated Cost of Lost Data* Across Various Industries in USD

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
*I.E., 500 transactions per second
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.
  • 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 Eliminates Data Collisions

Shadowbase ZDL+ Provides Support for Active/Active Architectures 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 Shadowbase ZDL+ because the replication engine automatically avoids them.

Table 2 compares the benefits of synchronous replication 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 possible4
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.
4By using ZDL+. Collisions may be avoided in both asynchronous and synchronous architectures by using a partitioned database or data-dependent routing.

Use Shadowbase ZDL to significantly reduce outage costs by avoiding any data loss, eliminating data collisions (ZDL+), 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.


Specifications are subject to change without notice, and delivery dates/timeframes are not guaranteed. Purchasing decisions should not be made based on this material without first verifying that the desired features are available on the desired platforms and environments.

NOTICE: This product does not guarantee that you will not lose any data; all user warranties are provided solely in accordance with the terms of the product License Agreement. Each user’s experiences will vary depending on its system configuration, hardware and other software compatibility, operator capability, data integrity, user procedures, backups and verification, network integrity, third party products and services, modifications and updates to this product and others, as well as other factors. Please consult with your supplier and review our License Agreement for more information.