Azure File Share Sync Storage Limitations

For the admins who are still thinking to replace their large file servers DFSR replication with Azure File Sync may hit a bottleneck if they do not have done the advance planning. Recently we have encountered an issue as you can see below, we have faced this issue when we have tried to run a sync on a file share of 4.5 TB. Although Azure File Share has max capacity limit of 5 TB still we have faced this issue.

While going through the MS documenataion we have found that there is a limitation with Azure File Sync End Point, although Azure File Supports upto 5 TB of storage but Azure File Sync end point as you can see below don’t support more than 4 TB.

Azure Files scale targets

Resource Standard file shares shares Premium file shares (preview)
Minimum size of a file share (no minimum; pay as you go) 100 GiB
Max size of a file share 5 TiB 5 TiB
Max size of a file in a file share 1 TiB 1 TiB
Max number of files in a file share No limit No limit
Max IOPS per share 1000 IOPS 5120 IOPS baseline
15,360 IOPS with burst
Max number of stored access policies per file share 5 5
Target throughput for single file share Up to 60 MiB/second Up to 612 MiB/sec (provisioned)
Maximum open handles per file 2,000 open handles 2,000 open handles
Maximum number of share snapshots 200 share snapshots 200 share snapshots

Azure File Sync scale target

Resource Target Hard limit
Storage Sync Services per subscription 15 Storage Sync Services No
Sync groups per Storage Sync Service 100 sync groups Yes
Registered servers per Storage Sync Service 99 servers Yes
Cloud endpoints per Sync Group 1 cloud endpoint Yes
Server endpoints per Sync Group 50 server endpoints No
Server endpoints per server 33-99 server endpoints Yes, but varies based on configuration (CPU, memory, volumes, file churn, file count, etc.)
Endpoint size 4 TiB No
File system objects (directories and files) per sync group 25 million objects No
Maximum number of file system objects (directories and files) in a directory 200,000 objects Yes
Maximum object (directories and files) name length 255 characters Yes
Maximum object (directories and files) security descriptor size 4 KiB Yes
File size 100 GiB No
Minimum file size for a file to be tiered 64 KiB Yes

Also as you can see in above error, it is advising to make each subfolder should sync in a separate sync group, which will become more work for the admin. So my advice is to do a PoC with various folder size and then plan your File Sync infrastructure accordingly.