TFS2015升级至TFS2018.2耗时异常，咨询预期升级时长

Hey Craig, thanks for reaching out with this question—it’s totally reasonable to wonder about that huge time difference between your two upgrade POCs. Let’s break down why your TFS 2015 to 2018.2 upgrade finished so fast, and what the expected timeline typically looks like.

Why Your 2018.2 Upgrade Was So Much Faster #

The biggest factor here is Microsoft’s ongoing optimizations to the TFS upgrade pipeline between 2017.3 and 2018.2. Here’s what changed:

• Streamlined database migration scripts: The 2018.2 upgrade reduced redundant data validation and migration steps that were present in the 2017.3 upgrade path from 2015. Many cross-version schema changes were optimized to run in parallel or skip unnecessary checks for intact 2015 databases.
• Improved index handling: The upgrade process now uses more efficient index rebuild and update logic, cutting down on the time spent optimizing database performance post-migration.
• Reduced pre-upgrade overhead: Unlike older versions, 2018.2’s installer does a better job of leveraging existing database statistics to avoid full table scans during validation.

What’s the Expected Upgrade Time for Your Scale? #

Upgrade timelines vary wildly based on three core factors: your collection’s size (database size, work item count, version control history), server hardware (CPU, memory, storage IOPS are critical), and pre-upgrade cleanup (like archiving old data or compressing databases).

As a general benchmark for collections similar to your POC:

• Small collections (<10GB database): 30 minutes to 2 hours
• Medium collections (10-50GB): 2-8 hours
• Large collections (50GB+ with extensive history): 8-24+ hours

Your 1-hour finish time falls well within the expected range for a medium-to-large collection that benefits from 2018.2’s optimizations—especially if your server hardware was consistent or improved between the two POCs.

Post-Upgrade Checks to Confirm Success #

Even without errors during installation, it’s smart to verify everything is working as expected:

• Check the health status of all collections in the TFS Administration Console
• Test core workflows: Create/edit work items, check in/out code, run a sample build
• Review Windows Event Viewer for any TFS-related warnings or hidden errors
• Validate reporting and analytics features (if you use them)

If all these checks pass, your fast upgrade is just a sign of the improved tooling in TFS 2018.2—no need to worry!

内容的提问来源于stack exchange，提问作者Craig Gordon