General migration performance guidance

This article explains the factors that influence performance when migrating content to SharePoint Online and OneDrive.

Migration performance can be impacted by network infrastructure, file size, migration time, and throttling. Understanding these will help you plan and maximize the efficiency of your migration.

Currently, Microsoft's SharePoint Migration Tool (SPMT) as well as several third party vendor tools utilize the SharePoint API for migration. It leverages Azure and uses channels for large content transfer. Regardless of which migration tool you use, these factors will apply. Follow the recommendations listed below for each phase of your migration process.

Before migration

Planning is the key to optimizing your migration. Determine what content you need to migrate, prioritize when the content needs to be migrated, and decide on what the optimal migration infrastructure should be.

I. Scan the source

The first rule of a good migration is to know your source; evaluate and triage your content before you migrate. What content really needs be migrated? What can be left behind? How many file versions should be included? The amount of content you migrate will determine the overall size of your project.

II. Package the content

This step is where the tool creates a proper package for the content to be imported into the cloud. This step is automated in SPMT and in most third-party tools.

Package size. To improve migration throughput, we recommend that you package at least 250 files per transfer. For the transfer size we recommend a minimum of 100MB and less than 250MB per package. This will result in a faster upload speed to Azure and leverages the scale capabilities of the migration API.

The following table provides estimates of the type of speed you may achieve based on the types of content you are migrating.

Type of metadata Examples Maximum
Light ISO files, video files 2 TB/day
Medium List items, Office files (~1.5MB) 1 TB/day
Heavy List items with custom columns, small files (~50kb) 250 GB /day
  • Large file size migrates faster than smaller ones. Small file size can result in larger overhead and processing time which directly impacts the performance.

  • Files migrate faster than objects and list items.

The speed of this step depends on the efficiency of the tool you are using and the type of content that you package. Splitting your packages in a smart way is something that will greatly improve this step. In addition, ensure that your permissions, sharing, or other limits are set up properly for migration and are within SharePoint Online limits and boundaries.

During migration

I. Upload to Azure

SPMT or your third-party tool will migrate your content into SharePoint Online using the Migration API, leveraging Azure as a temporary holding place.

If you have a good connection and can configure your datacenter, choose the same datacenter location closest geographically to you for your Azure and your Office 365 account. Migration data throughput is highest during off-peak hours, which are typically nights and weekends in your region's time zone. Your region's time zone is determined by where your SharePoint Online tenant is set up.

II. The Migration API

The final step of the migration process is when the data is moved from Azure to SharePoint Online. This action is transparent to the user when using SPMT or a third- party tool.

To improve throughput, users are encouraged to run parallel tasks against different site collections if possible. We recommend that you do not submit more than 5,000 migration jobs/requests at one time. Over-queuing the network will create an extra load on the database and slow migration down. Make sure your task has completed before you upload a new migration request. Some tools may already be doing this for you.

During migration, it is not uncommon for your migration task to be throttled. Throttling is implemented to ensure the best user experience and reliability of SharePoint Online. It is primarily used to load balance the database and can occur if you misconfigure migration settings, such as migrating all your content in a single task or attempting to migrate during peak hours.

For more technical background and information, please see

After migration

After the migration is completed, verify that your content has been successfully moved to SharePoint Online or OneDrive.

FAQ and Troubleshooting

Question: I am experiencing poor performance or throttling during migration. Answer: Please check up guidance in this document, plus refer to Please refer to Avoid getting throttled or blocked in SharePoint Online for more information on Microsoft throttling guidance. For specific tools configuration or questions, please contact your third party tools vendor for more information.

Question: I'm continually getting throttled while I am attempting to migrate. Can Microsoft turn off the throttle to help me with migration?
Answer: Throttling is in place to protect the reliability and availability of the service. Throttling rules cannot be disabled or suspended. Please refer to Avoid getting throttled or blocked in SharePoint Online for more information.

Question: My migration is blocked with consistent high volume of Http 503 errors (“Server Too Busy”) ?
Answer: If you are experiencing a high volume of HTTP 503 responses blocking your migration for extended period of time, please follow the steps below to create a support ticket.

  1. Navigate to https://admin.microsoft.com
  2. Ensure you are using the new admin center preview.

Note

If you are using the old M365 admin center you can skip step 8 as the “Description” field will not exist.

  1. On the left navigation pane click Support and then New Service Request.

    New service request

This will activate the Need Help? pane on the right-hand side of your screen.

  1. In the Briefly describe your issue area, enter "SharePoint Migration Throttling with 503".

    need help

  2. Click Contact Support.

  3. Under Description enter “SharePoint Migration Throttling with 503”.

    Contact support

  4. Fill out the remaining information and click Contact me.

  5. Once the ticket has been created please ensure you provide the support agent with the following information:

  • How much is left of your migration (x TB?)
  • Migration start and end date
  • Describe where you are migrating your content from, such as SharePoint Server, Box, GDrive, File shares, etc.
  • Estimate the number of throttles (e.g. x throttle per hour?) and when (specific time and date) did the throttling happened
  • Which migration tool you are using (e.g. SPMT, Sharegate, Mover, etc.)


Question: I am planning to migrate (> 100 TB), is there any preparation needed?
Answer: For a larger than 100TB migration, please submit a support request with following steps and please include the information below.

Follow these steps:

  1. Navigate to https://admin.microsoft.com
  2. Ensure you are using the new admin center preview.

Note

If you are using the old M365 admin center you can skip step 8 as the “Description” field will not exist.

  1. On the left navigation pane click Support and then New Service Request.

    New service request

This will activate the Need Help? pane on the right-hand side of your screen.

  1. In the Briefly describe your issue area, enter "SharePoint Migration over 100TB".

    need help

  2. Click Contact Support.

  3. Under Description enter “SharePoint Migration over 100TB”.

    Contact support

  4. Fill out the remaining information and click Contact me.

  5. Once the ticket has been created please ensure you provide the support agent with the following information:

  • Estimated size of your migration:
  • An estimate of when you would like to start and complete your migration:
  • Where you are migrating your content from, such as SharePoint Server, Box, GDrive, File shares, etc:


Avoid getting throttled or blocked in SharePoint Online