Backup speed does not match available bandwidth

Overview

Sometimes the backup rate you see from the CrashPlan app is different from the bandwidth offered by your Internet Service Provider (ISP). The purpose of this article is to explain how the CrashPlan app's effective transfer rate differs from the bandwidth provided by your ISP, as well as some of the factors outside of CrashPlan's control that can affect backup rates.

Before you begin

Review How CrashPlan backup works.

Network considerations

  • CrashPlan cloud environments share bandwidth when backing up. As a result, upload speeds may not match maximum speeds of an individual’s Internet provider.
  • CrashPlan monitors usage across our data centers and strategically adds capacity (servers, storage and bandwidth) to our infrastructure to deliver the best upload speeds we can.

Why backup speed and bandwidth differ

Bandwidth is a measure of theoretical network capacity. In real world applications, the actual achieved throughput from a device or application will differ from this theoretical maximum. The protocols that your devices use to communicate over the Internet take up overhead, bandwidth is shared with other applications, and network latency can slow down connections.

CrashPlan compresses your backed up data before uploading it, causing your backup speed to differ from the network bandwidth and throughput. This usually results in the effective transfer rate being higher than the actual transfer rate. For example: a user has 10 GB of data on her system to be backed up. After the CrashPlan app compresses and encrypts the data, it now takes up only 8 GB of space. Their CrashPlan app transfers that 8 GB of data at an actual transfer rate of 1 Mbps. However, the effective transfer rate is actually 1.25 Mbps, or 25 percent higher, due to the data compression.

The backup speed is not the same thing as bandwidth or throughput:

  • Bandwidth is a theoretical maximum, and applies only to your connection to your ISP, not the Internet in general.
  • Actual throughput or file transfer speed is the performance that your device sees in actual operation.
  • Backup speed and effective transfer rate depend on both of the above, and also on data compression and other factors, as described below.

Upload versus download speeds

ISPs often provide different amounts of bandwidth for downloads and uploads. The download speed is typically greater than the upload speed. Ask your ISP about the level of service you have purchased and verify it using a freely-available internet speed test to determine if your network speed might be the cause of a slow backup speed.

Other facts to keep in mind:

  • Backups are an upload operation, because the data is going from your device to the CrashPlan cloud.
  • Restores are a download operation, because the data is going from the CrashPlan cloud to your device.

What you can expect

The CrashPlan cloud is a shared service, which means that upload and download speeds depend on the number of users connected at any given point. The CrashPlan app estimates the total time it will take to upload your data based on the current network environment. The time remaining appears on the Home screen. This estimation will vary over the duration of your first backup.

If you have a large backup selection, configure the CrashPlan app further to optimize your backup.

Our goal is to provide secure and reliable backup. We work like other services that share resources with a pool of users. Individual speeds vary depending on the number of simultaneous users and how much they are uploading. We do not throttle your backup or restores. We also do not limit file sizes.

External factors affecting backup speed

Various factors outside of CrashPlan's control affect your backup and restore speed. The effective transfer rate between your device and our data centers depends on the bandwidth provided by your ISP, as well as network speeds on nodes between your ISP and our data centers. Even if a speed test of your ISP shows that your currently available bandwidth is high, network congestion elsewhere can cause speeds to slow down. The effective network speed between the CrashPlan app and CrashPlan's servers affect the backup and restore speed.

What you can do

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