SDS has some known limits you should be aware of:
Number of Sync Profiles – SDS cannot process more than five syncs simultaneously.
Number of domains per profile – Each sync profile can append one domain for the teacher identity matching configuration and one domain for the student identity matching configuration. If you need more than two domains appended to match all students and teachers, you must create additional sync profiles.
Number of users/rosters per profile– Each sync profile using CSV files may contain no more than two million rows in a single CSV file. Two million rows per CSV file is the defined limit. Typically, the studentenrollment.csv contains the most rows. We also typically see averages of 8 classes per student in the enrollment file. Using this average, you should never plan to have more than 250,000 students per sync profile with CSV files. (250,000 students x 8 classes per student = two million rows in the studentenrollment.csv) Maintaining 200,000 students or less per profile is a good rule of thumb. If you intend to sync more than the recommended number of users, you should contact the SDS Onboarding Team.
Number of errors per sync profile – Each sync profile can only incur up to 15,000 errors. Once a sync profiles hits that error limit, the sync will stop, and the profile will stop processing the data. The only way to remediate this is to correct some of the errors by making updates to the source or target directory and then restart the sync process.