Remote Differential Compression: The Complete Guide

Remote differential compression, a cornerstone of efficient data transfer, addresses challenges within distributed systems. Specifically, Microsoft's implementation of remote differential compression optimizes bandwidth usage across wide area networks. The underlying algorithm of remote differential compression focuses on transmitting only the differences between files, a crucial technique that benefits applications like file synchronization tools. Furthermore, the mathematical foundation of remote differential compression contributes to data deduplication, ensuring redundant data is minimized for storage efficiency.

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We live in an era defined by exponential data growth. Every sector, from healthcare to finance to entertainment, is generating, processing, and storing unprecedented volumes of information. This relentless data explosion presents significant challenges to network infrastructure and the systems that rely on it. The ability to move and synchronize this data efficiently has become a critical bottleneck.

The Data Deluge: A Strain on Infrastructure

The sheer scale of data being created daily is staggering. Social media interactions, IoT device telemetry, scientific research, and business analytics all contribute to this ever-increasing tide.

This unprecedented growth places immense strain on existing network infrastructure. Traditional methods of file transfer and data synchronization often struggle to keep pace.

Organizations face escalating costs associated with bandwidth consumption, longer transfer times, and increased infrastructure demands.

Common Roadblocks in Data Movement

Moving large files or synchronizing data across distributed locations often encounters numerous obstacles. These include:

• Bandwidth Limitations: Insufficient bandwidth can significantly slow down transfer speeds, leading to delays and frustrated users.

• Network Latency: High latency, especially over Wide Area Networks (WANs), adds significant overhead to data transfer, impacting performance.

• Data Redundancy: Transferring entire files, even when only small portions have changed, wastes valuable bandwidth and resources.

• Synchronization Inefficiencies: Traditional synchronization methods can be inefficient, especially when dealing with large datasets or frequent updates.

These challenges can impact productivity, increase operational costs, and hinder an organization's ability to leverage its data effectively.

Remote Differential Compression: A Bandwidth Optimization Solution

Remote Differential Compression (RDC) emerges as a targeted solution to address these data transfer challenges.

RDC is a powerful technology designed to optimize bandwidth usage during file transfer and data synchronization.

By intelligently identifying and transferring only the differences between files, RDC drastically reduces the amount of data transmitted over the network. This approach minimizes bandwidth consumption, accelerates transfer times, and improves overall network efficiency. In essence, RDC focuses on transmitting "what's new" rather than resending everything.

The challenges associated with data movement outlined above make it clear that strategies for optimizing bandwidth are no longer a luxury, but a necessity. This is where Remote Differential Compression (RDC) enters the picture, offering a streamlined approach to data transfer, particularly across wide area networks. Let's unpack what RDC is and how it addresses these challenges head-on.

What is Remote Differential Compression (RDC)? Unveiling the Core Concepts

At its core, Remote Differential Compression (RDC) is a data compression algorithm designed to efficiently transfer files between two computers, especially over networks with limited bandwidth, such as Wide Area Networks (WANs). It achieves this by transferring only the differences (or "delta") between two versions of a file, rather than the entire file itself.

RDC and the WAN Challenge

WANs, by their nature, present significant bandwidth limitations and often suffer from high latency. Traditional file transfer methods can become extremely slow and resource-intensive in these environments.

RDC directly tackles these challenges by minimizing the amount of data that needs to be transmitted. Instead of resending an entire file when only a small part of it has changed, RDC identifies and transfers only the modified portions.

This results in several key benefits, including:

• Reduced Bandwidth Consumption: By transmitting only the "delta," RDC dramatically reduces the amount of bandwidth consumed during file transfers.

• Faster Transfer Times: Smaller data transfers translate directly into faster transfer times, improving user experience and productivity.

• Improved Network Efficiency: Reduced bandwidth consumption frees up network resources for other critical applications.

Delta Encoding: The Engine of RDC

The magic behind RDC lies in a process called delta encoding. Delta encoding is a data compression technique that stores data as a series of differences (deltas) between sequential data, rather than complete files.

In the context of RDC, delta encoding works as follows:

1. File Analysis: RDC analyzes two versions of a file to identify the differences between them.

2. Delta Generation: It then creates a "delta," which is a compact representation of these differences.

3. Differential Transfer: Only this delta is transferred across the network.

4. Reconstruction: The receiving computer uses the delta to reconstruct the updated version of the file.

Imagine updating a large document with only a few minor edits. Without RDC, the entire multi-megabyte document would need to be re-sent. With RDC and delta encoding, only the few kilobytes representing the changes are transmitted, offering a substantial bandwidth saving.

The reduced bandwidth consumption and faster transfer times afforded by RDC are undoubtedly appealing. But to truly appreciate the impact of RDC, it’s crucial to understand how it achieves these benefits. Let's delve into the technical intricacies that make RDC such an effective data transfer solution.

Diving Deep: How RDC Works – A Technical Exploration

At its heart, Remote Differential Compression relies on the principle of delta encoding. But how does this translate into tangible bandwidth savings? The magic lies in the algorithm's ability to pinpoint and transmit only the necessary changes.

Unpacking Delta Encoding: Finding the Differences

Delta encoding is the engine that drives RDC's efficiency. It is a process that identifies the differences between two versions of a file. Instead of treating the updated file as an entirely new entity, delta encoding meticulously compares it to the original.

It then creates a "delta," a compact representation of the modifications. This delta contains instructions on how to reconstruct the newer version. These instructions are based on the original file. Think of it like a patch for a software program: it only includes the code that needs to be changed, rather than the entire program.

The core steps include:

• Chunking: Dividing both files into smaller, manageable segments.
• Hashing: Generating unique hash values for each segment.
• Comparison: Comparing the hash values to identify identical, modified, or new segments.
• Delta Creation: Constructing the delta file with instructions to recreate the new file. This includes references to unchanged segments in the original file. It also includes the actual data for new or modified segments.

The RDC File Transfer Process: A Step-by-Step Breakdown

The efficiency of RDC stems from a carefully orchestrated process involving both the client and the server. Let's break down this process into distinct steps.

Client-Side Hashing: Fingerprinting the Data

The client initiates the process by dividing the updated file into smaller chunks. It then generates a unique hash value (a digital fingerprint) for each chunk. These hash values are significantly smaller than the original data.

These hash values are then sent to the server. This is a crucial step in minimizing the initial data transmitted over the network.

Server-Side Comparison: Identifying the Changes

The server, which possesses the original version of the file, performs a similar hashing process on its own version. It then compares the hash values received from the client with its own set of hash values.

This comparison allows the server to identify which chunks are identical in both files. It also allows the server to identify which chunks have been modified or are entirely new.

Differential Transfer: Sending Only What's Needed

Based on the comparison, the server determines the minimal set of data required to update the client's version of the file.

This data, the "delta," is then transmitted to the client. It consists of the actual data for the new or modified chunks. It also contains references to the unchanged chunks, which the client already possesses. The client then uses this delta to reconstruct the latest version of the file.

Bandwidth Optimization: The Result of Delta Encoding

Delta encoding's optimization of bandwidth is substantial. Here's why:

• Reduced Data Volume: Only the differences are transferred, significantly reducing the amount of data traversing the network.
• Lower Network Congestion: Less data leads to reduced network congestion, improving overall network performance.
• Faster Transfers: Reduced data volume directly translates to faster transfer times.
• Efficient Resource Utilization: Bandwidth savings free up network resources for other critical applications.

By focusing on transmitting only the changes, RDC ensures that bandwidth is used efficiently. This, in turn, accelerates file transfers and improves overall network performance.

The reduced bandwidth consumption and faster transfer times afforded by RDC are undoubtedly appealing. But to truly appreciate the impact of RDC, it’s crucial to understand how it achieves these benefits.

Let's delve into the technical intricacies that make RDC such an effective data transfer solution. With the mechanics of RDC laid bare, it’s time to shift our focus from theory to practice. How does RDC translate into real-world value? Let’s explore some compelling use cases.

RDC in Action: Real-World Applications and Use Cases

Remote Differential Compression isn't just a theoretical concept. It's a practical technology that solves real-world data transfer challenges across various scenarios. Its ability to minimize bandwidth consumption and accelerate transfer speeds makes it invaluable in environments where efficient data handling is critical.

Let's examine some key applications of RDC. These include data synchronization, its integral role within Microsoft's Windows Server ecosystem, and its contribution to optimized client-server architectures.

Data Synchronization Scenarios

Data synchronization involves keeping data consistent across multiple locations or devices. This is crucial for collaboration, backup, and disaster recovery. RDC excels in these scenarios, particularly over wide area networks (WANs) where bandwidth is often a constraint.

Imagine a scenario where a large design firm has offices in multiple cities. Each office needs to have the latest versions of CAD files and project documents.

Without RDC, synchronizing these files would require transferring the entire file each time a change is made, consuming significant bandwidth and time. With RDC, only the differences between the files are transferred.

This dramatically reduces the bandwidth required and speeds up the synchronization process. This allows designers in different locations to collaborate effectively without being hampered by slow data transfers.

Another common use case is mobile device synchronization. When users back up their phones or tablets to a cloud service, RDC can ensure that only new or modified data is uploaded. This saves valuable bandwidth for both the user and the service provider.

This approach is particularly beneficial in areas with limited or expensive internet access. It also ensures that backups complete quickly, minimizing disruption to the user experience.

Microsoft's Implementation of RDC in Windows Server

Microsoft has deeply integrated RDC into Windows Server to optimize data transfer for various services and features. One prominent example is its use in BranchCache, a wide area network (WAN) bandwidth optimization technology.

BranchCache caches content from central servers at branch office locations. When a user in the branch office requests a file, BranchCache first checks if the content is already available locally.

If not, it uses RDC to retrieve only the changed portions of the file from the central server or a peer in the branch office. This significantly reduces the amount of data that needs to be transferred over the WAN, improving application response times and reducing bandwidth costs.

Microsoft also employs RDC in Distributed File System Replication (DFSR). DFSR is a role service in Windows Server that enables you to efficiently replicate folders and files across multiple servers.

RDC ensures that only the differences between files are replicated, minimizing bandwidth usage. This is particularly important for organizations with multiple branch offices or servers that need to keep their data synchronized.

By integrating RDC into these core services, Microsoft provides a powerful and transparent way for organizations to optimize their data transfer infrastructure.

RDC in Client-Server Environments

RDC plays a vital role in optimizing data transfer within client-server environments. This is particularly true for applications that involve frequent updates or large file transfers.

Consider a software distribution scenario. When a software vendor releases a new version of its application, it needs to distribute the update to its clients. Using RDC, the vendor can create a delta package that contains only the changes between the old and new versions of the software.

Clients can then download this smaller delta package and apply it to their existing installation. The result is a much faster and more efficient update process. This reduces the load on the vendor's servers and minimizes the impact on the client's network.

Another example is virtual desktop infrastructure (VDI) environments. In VDI, user desktops are hosted on central servers and streamed to client devices. RDC can be used to optimize the transfer of desktop images and user profiles.

By transferring only the changes made to the desktop image or profile, RDC reduces the bandwidth required and improves the user experience. This is especially important for organizations with a large number of VDI users or those with limited network bandwidth.

In essence, RDC in client-server architectures means faster updates, reduced bandwidth consumption, and improved overall performance, all contributing to a better user experience and more efficient resource utilization.

The ability of RDC to minimize bandwidth consumption and accelerate transfer speeds makes it invaluable. So, why should you specifically choose RDC? What are the tangible advantages that make it a compelling solution in today's data-intensive environment?

The Benefits Unveiled: Why Choose RDC?

Remote Differential Compression offers a multitude of benefits that translate into significant improvements in data transfer efficiency, cost savings, and overall user experience. Its strengths become particularly apparent when dealing with large files or frequent data synchronization across a wide area network.

Quantifiable Bandwidth Reduction

One of the most compelling reasons to adopt RDC is the substantial reduction in bandwidth consumption it offers. Unlike traditional file transfer methods that require transmitting entire files, RDC intelligently identifies and transfers only the differences (or deltas) between files.

This delta encoding approach can dramatically decrease the amount of data transmitted, especially when dealing with files that undergo incremental changes.

The actual reduction in bandwidth consumption varies depending on the file types, the size of the changes, and the frequency of synchronization. However, in many real-world scenarios, RDC can reduce bandwidth usage by as much as 80-90% compared to traditional methods. This efficiency is a game-changer for organizations operating across geographically dispersed locations or those with limited bandwidth resources.

Accelerated File Transfer and Enhanced User Experience

Reduced bandwidth consumption directly translates into faster file transfer times. By transmitting only the necessary data, RDC significantly reduces the amount of time required to synchronize or transfer files.

This improvement in transfer speeds has a profound impact on user experience. Users experience less waiting time, leading to increased productivity and satisfaction.

Imagine a scenario where remote workers need to access and update large design files on a central server. Without RDC, these transfers could take a significant amount of time, leading to frustration and delays.

With RDC, however, the transfer of changes is significantly faster, providing a seamless and responsive user experience. This enhanced efficiency extends beyond individual users, benefiting teams and entire organizations by streamlining workflows and improving collaboration.

Enhanced Data Synchronization and Integrity

Data synchronization is critical for ensuring consistency and accuracy across multiple locations or devices. RDC plays a crucial role in enhancing this process. By minimizing the amount of data transferred, RDC reduces the risk of errors and inconsistencies during synchronization.

This is especially important in environments where data integrity is paramount, such as financial institutions or healthcare organizations.

Furthermore, the reduced transfer times contribute to faster synchronization cycles, ensuring that all locations have access to the latest data in a timely manner. RDC's ability to efficiently transfer only the changes also makes it easier to track and manage updates, improving overall data governance and control.

Cost Savings on Wide Area Networks (WANs)

The benefits of RDC extend beyond performance and user experience, directly impacting the bottom line through significant cost savings.

By reducing bandwidth consumption on WANs, RDC helps organizations lower their network infrastructure costs. This includes reduced expenses associated with bandwidth usage, data transfer fees, and network maintenance.

Moreover, the improved transfer speeds and reduced downtime associated with RDC contribute to increased productivity, further enhancing cost efficiency. In the long run, the investment in RDC can yield substantial returns by optimizing resource utilization, minimizing operational expenses, and improving overall business agility.

Reduced bandwidth consumption directly translates into faster file transfer times. By transmitting only the necessary data, RDC significantly reduces the amount of time required to synchronize or transfer files.

This improvement in transfer speeds has a cascading effect, enhancing user experience and boosting overall productivity. However, like any technology, RDC isn't a silver bullet. It's important to consider the potential downsides and limitations to determine if it's the right fit for your specific needs.

Considerations and Limitations: Understanding the Trade-offs

While Remote Differential Compression offers a compelling array of advantages, it's crucial to acknowledge its limitations and potential drawbacks. A thorough understanding of these trade-offs is essential for making informed decisions about its implementation.

RDC introduces complexities that must be carefully considered to avoid unintended consequences.

The Computational Overhead of Delta Encoding

RDC's delta encoding, while efficient in reducing bandwidth, introduces a significant computational overhead. Calculating the differences between files requires processing power on both the sending and receiving ends.

This computational burden can be particularly noticeable when dealing with very large files or when synchronizing data across numerous clients simultaneously.

The hashing algorithms and comparison processes involved can consume significant CPU resources, potentially impacting the performance of servers and clients, especially if they are already under heavy load.

Therefore, it's essential to assess the processing capabilities of your infrastructure before implementing RDC to ensure that it can handle the additional workload without causing bottlenecks.

Security Considerations in RDC Implementation

Security is another critical aspect to consider when using RDC. Because RDC transmits portions of files, albeit only the differences, it's imperative to ensure that these data fragments are protected during transit.

Standard encryption protocols, such as TLS/SSL, should be employed to secure the communication channels and prevent unauthorized access to the data.

Additionally, organizations should implement robust access control measures to restrict who can access and modify files, both at the source and destination.

Furthermore, it's important to regularly audit RDC implementations to identify and address any potential security vulnerabilities. Failure to address these concerns could expose sensitive data to unauthorized access or modification.

Scenarios Where RDC Might Not Be Optimal

While RDC excels in many data transfer scenarios, it's not a universal solution. There are situations where its benefits are diminished, or alternative approaches may prove more effective.

For instance, when transferring small files or files that undergo substantial changes with each iteration, the overhead of calculating deltas might outweigh the benefits of reduced bandwidth consumption. In such cases, traditional file transfer methods might be faster and more efficient.

Also, in environments with abundant bandwidth and low latency, the advantages of RDC become less pronounced.

In these scenarios, the computational overhead might not justify the marginal gains in transfer speed or bandwidth savings.

Finally, certain file types, such as highly compressed or encrypted files, may not be suitable for RDC. The delta encoding process relies on identifying patterns and similarities between files, which might be difficult or impossible to achieve with highly compressed or encrypted data.

Therefore, it's essential to carefully evaluate the specific characteristics of your data and network environment before deciding whether RDC is the optimal solution.

Security is another critical aspect to consider when using RDC. Because the algorithm works by identifying and transferring differences, there is a risk that malicious actors could potentially analyze these differences to infer information about the original data.

Therefore, it's crucial to implement appropriate security measures, such as encryption and access controls, to protect sensitive data during the transfer process. Now, let's look at how to get RDC up and running and how to ensure it works optimally within your infrastructure.

Implementing RDC: A Practical Guide to Setup and Optimization

Implementing Remote Differential Compression (RDC) requires careful planning and execution to maximize its benefits. This section provides a practical guide to setting up RDC, optimizing its performance, and troubleshooting common issues. We'll focus primarily on the Windows Server environment, where RDC is most commonly utilized.

Enabling RDC in Windows Server

RDC is a feature that can be enabled within Windows Server. The process is relatively straightforward, but it's essential to follow the steps precisely to avoid any configuration issues.

Step-by-Step Instructions

1. Access Server Manager: Open Server Manager on your Windows Server. This is your central console for managing server roles and features.

2. Add Roles and Features: Click on "Add roles and features" to start the Add Roles and Features Wizard.

3. Select Installation Type: Choose "Role-based or feature-based installation" and click "Next."

4. Select Target Server: Select the server where you want to enable RDC. This is typically the server that will be involved in data synchronization or file transfer.

5. Select Features: In the "Features" section, expand "Remote Differential Compression" and select the "Remote Differential Compression" checkbox.

6. Confirm Installation: Review your selections and click "Install."

7. Restart if Prompted: If prompted, restart the server to complete the installation.

Once the installation is complete, RDC is enabled at the server level. Applications that support RDC can now leverage its capabilities for optimized data transfer.

Best Practices for Optimizing RDC Performance

Enabling RDC is just the first step. To truly harness its potential, you need to optimize its performance. Several factors can influence RDC's efficiency, including network configuration, file sizes, and the types of files being transferred.

Network Configuration

• Minimize Latency: RDC is most effective when network latency is low. High latency can negate the benefits of delta encoding. Ensure your network infrastructure is optimized for minimal latency.

• Optimize Bandwidth: While RDC reduces bandwidth consumption, it's still essential to have sufficient bandwidth available. Monitor network traffic to identify and resolve any bandwidth bottlenecks.

File Optimization

• File Fragmentation: Defragmenting your hard drives regularly can improve RDC performance. Fragmented files make it more difficult for RDC to identify differences efficiently.

• File Types: RDC works best with files that have a high degree of similarity. Certain file types, such as large media files or databases, may benefit less from RDC than others. Consider the types of files you are transferring and whether RDC is the right solution for them.

RDC Tuning Parameters

While Windows Server manages RDC automatically, some advanced tuning parameters can be adjusted through registry settings. These settings should be modified with caution, as incorrect values can negatively impact performance.

• HashCacheSize: Adjust the size of the hash cache used by RDC. Increasing the cache size can improve performance when dealing with large files, but it also consumes more memory.

• SignatureCacheSize: Similar to the hash cache, the signature cache stores signatures of file blocks. Adjusting its size can impact performance, especially when synchronizing numerous small files.

Note: Modifying registry settings requires advanced knowledge and should only be performed by experienced administrators. Always back up your registry before making any changes.

Troubleshooting Common RDC-Related Problems

Despite its advantages, RDC can sometimes encounter issues. Here are some common problems and their solutions:

Slow Transfer Speeds

If you're experiencing slow transfer speeds even with RDC enabled, consider the following:

• High CPU Usage: Check the CPU usage on both the sending and receiving servers. High CPU usage can indicate that the computational overhead of delta encoding is impacting performance.

• Network Congestion: Verify that there is no network congestion between the servers. Use network monitoring tools to identify any bottlenecks.

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• Firewall Issues: Ensure that firewalls are not blocking RDC traffic. RDC typically uses standard TCP ports, but it's essential to verify firewall rules.

Synchronization Errors

Synchronization errors can occur if there are inconsistencies between the files being transferred.

• File Corruption: Check for file corruption on both the sending and receiving servers. Corrupted files can lead to synchronization errors.

• Version Conflicts: Ensure that the correct file versions are being synchronized. Version conflicts can occur if files are modified simultaneously on different servers.

RDC Not Working

If RDC is not working at all, verify the following:

• RDC Enabled: Confirm that RDC is enabled on both the sending and receiving servers.

• Application Support: Ensure that the application you are using supports RDC. Not all applications are designed to take advantage of RDC's capabilities.

• Event Logs: Check the event logs for any RDC-related errors. The event logs can provide valuable information about the cause of the problem.

By carefully following these steps and best practices, you can effectively implement and optimize RDC to significantly improve data transfer efficiency within your Windows Server environment.

The Future of RDC: Evolution and Emerging Technologies

Having explored the practicalities of implementing RDC, it's time to consider what lies ahead for this technology. As data volumes continue to surge and network landscapes evolve, it's critical to assess the long-term viability and potential adaptations of RDC. What role will it play in the face of emerging technologies and ever-increasing bandwidth demands?

The Shifting Landscape of Bandwidth Optimization

Emerging technologies are rapidly reshaping the landscape of bandwidth optimization. Cloud computing, edge computing, and the proliferation of IoT devices are driving the need for more efficient data transfer solutions.

• Cloud Computing and RDC: The widespread adoption of cloud services presents both challenges and opportunities for RDC. While cloud providers offer robust infrastructure and high bandwidth, the need for efficient data synchronization between on-premises systems and the cloud remains crucial. RDC can play a significant role in minimizing bandwidth costs and accelerating data migration to the cloud.

• Edge Computing's Impact: Edge computing, where data processing occurs closer to the source, introduces new considerations. RDC can be leveraged to efficiently synchronize data between edge devices and central servers, reducing latency and minimizing bandwidth consumption across wide area networks.

• IoT and the Data Deluge: The Internet of Things (IoT) is generating massive amounts of data. Optimizing the transfer of this data from IoT devices to data centers or cloud platforms is essential. RDC's delta encoding capabilities are well-suited for efficiently handling the incremental updates characteristic of many IoT applications.

The Enduring Relevance of Delta Encoding

Despite advancements in networking technologies, the fundamental principles of delta encoding remain highly relevant. The ability to identify and transfer only the differences between files offers a significant advantage in bandwidth-constrained environments.

Newer compression algorithms and data transfer protocols may offer improved performance in certain scenarios. However, delta encoding's simplicity and effectiveness continue to make it a valuable tool for optimizing data transfer in a wide range of applications.

Moreover, delta encoding is not a static technology. Research and development efforts are ongoing to enhance its performance and adapt it to new data types and network environments.

Microsoft's Continued Investment in Data Transfer Technologies

Microsoft has long been a proponent of RDC, integrating it into various Windows Server features and data synchronization tools. The company's ongoing development efforts in data transfer technologies suggest a continued commitment to efficient data management.

It is important to note that Microsoft regularly releases updates and enhancements to its data transfer protocols and algorithms. By keeping a close eye on these developments, organizations can leverage the latest advancements in bandwidth optimization and data synchronization.

The Future: Hybrid Approaches and Intelligent Optimization

The future of RDC likely involves a hybrid approach, combining delta encoding with other optimization techniques to achieve maximum efficiency. Intelligent algorithms that can dynamically select the most appropriate data transfer method based on network conditions and data characteristics will become increasingly important.

Moreover, the integration of machine learning techniques could further enhance RDC's performance. For example, machine learning models could be used to predict file changes and optimize delta encoding parameters, resulting in even greater bandwidth savings.

Ultimately, the future of RDC lies in its ability to adapt and evolve in response to the ever-changing demands of the data-driven world. By embracing new technologies and continuing to innovate, RDC can remain a cornerstone of efficient data management for years to come.

Video: Remote Differential Compression: The Complete Guide

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So, that's remote differential compression in a nutshell! Hopefully, you now have a solid understanding of how this clever technology works and how it can make your data transfers much more efficient. Give remote differential compression a try – you might be surprised at the difference it makes!