Migration options and limits
Read this before running a large migration. It explains the job options in Migrate existing files and the cases migration will not handle.
Large files
Section titled “Large files”Most documents are small and migrate in a single server-side step. Files above about 4 MB need Stream Large Files turned on for the job, and a provider that supports multipart upload: Amazon S3, Google Cloud Storage, Azure Blob Storage, Sliick Cloud Storage or SharePoint.
With streaming on, a large file is copied in chunks entirely server-side. There is no browser involved and no tab to keep open. A single file streams across as many background steps as it needs and resumes where it left off, so there is no practical per-file size cap beyond the provider’s own object limit.
If streaming is off, or the provider does not support it, large files are skipped and reported rather than failing the job.
For your own storage, the bytes never transit Sliick infrastructure. The copy runs from Salesforce straight to your storage.
Verification
Section titled “Verification”Every migrated file is verified before its original can be deleted. There are three tiers:
| Tier | What it checks | When |
|---|---|---|
| Length | The stored file’s byte length matches the source | Always on |
| Per-chunk and composite | Each streamed part carries a checksum the store validates on receipt, and the assembled file’s composite checksum is recomputed and must match. A mismatch fails the file | Streamed Amazon S3 uploads. Other providers verify by length; SharePoint cannot expose a per-chunk checksum |
| Read-back | The stored file is re-read and compared to the source. The strongest guarantee, and it doubles transfer cost | Opt-in with Verify Read-Back, off by default |
A file’s tier is shown per row in the job detail view. With Delete Originals on, an original is only removed after its copy reaches an eligible verification status, and for images, finishes processing.
Images and media processing
Section titled “Images and media processing”Migrated images are run through media processing only when it is enabled, because it costs real money to run. When it is on, migrated images are queued and processed at a steady, throttled rate, one at a time in the background, so a large migration does not spike your usage.
When media processing is off, migrated images are marked complete immediately and cost nothing to process. They still display everywhere: the gallery and file list fall back to the full-resolution image wherever a thumbnail would normally be used, which is heavier on bandwidth but works. You can enable media processing later and use per-file Retry to generate thumbnails on demand. See Media processing for images.
Files shared across several records
Section titled “Files shared across several records”One Salesforce file can be linked to many records at once: the same file on an Account and a Case, or on several Accounts. Sliick’s file model associates each migrated file with one record, so it cannot yet represent a file that legitimately belongs to several.
Rather than collapse a shared file onto one record, and silently strip it from the others when Delete Originals removes the native original, migration skips shared files and leaves them untouched:
- A file linked to more than one business record is counted under Shared across records and is not migrated. Its Salesforce file, and every one of its record links, stays exactly as it is.
- Two link types do not count as sharing: the owning user’s automatically created link, and Library membership. A file on a single record that also sits in a Library migrates normally.
- These files stay fully usable through Salesforce’s standard Files related list on each record. They are simply not under Sliick management.
If you need a shared file in Sliick now, remove the file’s links to all but one record so it is attached to a single record, then re-run the migration for that record’s object.
Notes and limits
Section titled “Notes and limits”- Concurrent edits during a migration are your responsibility. Remove the file list and image gallery components from the page layout, or run during a quiet window, while a large job runs.
- Salesforce as the target re-points existing files into Sliick without copying any bytes. The latest version only.
- Legacy Attachment records are out of scope. Migrate them to Files first with Salesforce’s own tool.
- Very large files can only be exercised in a production or sandbox org. Scratch and developer orgs cap a single file at roughly 50 MB and 20 MB respectively.