RSMF slicing configuration reference

This page explains where Relativity Short Message Format (RSMF) slicing happens, what the Slice by processing profile setting does, and how to slice a conversation again after processing.

RSMF slicing overview

Slicing splits one conversation into more than one RSMF document. Each resulting document is a slice. A slice behaves like any other document in your workspace, meaning you can review, image, and produce it.

Conversations are split for two different reasons:

Time-based slicing—Relativity groups messages into time blocks during processing, so a conversation that runs for months becomes a set of documents sized for review.
Reviewer-driven slicing—a reviewer selects specific events in the Short Message Viewer and saves them as a new document.

Slicing differs from filtering. Filtering changes which events the Short Message Viewer displays. Slicing creates a new document.

Where slicing happens

Four separate things can split a conversation. The processing profile controls only one of them. Identifying which one applies to your data answers most slicing questions.

Split point	What controls it	When it occurs
Source or collection tool	The export settings of the tool that generates the RSMF.	Before the file reaches Relativity.
Short message conversion	The Slice by setting on the processing profile.	During processing.
RSMF file limits	Fixed limits for file size and event count.	During processing.
Short Message Viewer	Reviewer event selection.	After publish.

Slicing at the source

Some tools slice a conversation as they generate the RSMF. When this happens, the file arrives in Relativity already sliced, and the slice boundaries reflect the settings of that tool rather than any Relativity setting.

Short message conversion settings apply only to processing jobs that convert source data into RSMF. They have no effect on data that is already in RSMF format when processing begins. A Slice by value therefore does not change files that arrive as RSMF.

This distinction matters most for Cellebrite data, which reaches Relativity by one of two routes:

You upload a Universal Forensic Extraction Device Report (UFDR) file. Relativity converts the UFDR to RSMF during processing and applies the Slice by value from the profile.
You upload RSMF files exported from Cellebrite Physical Analyzer. Cellebrite has already sliced the conversations. Relativity preserves those boundaries, and the Slice by value has no effect.

To apply Relativity slice boundaries to Cellebrite data, process the original UFDR file rather than exported RSMF files. For supported input formats, see Short message conversion for Cellebrite.

Slicing during short message conversion

When Relativity converts Slack, Microsoft Teams, Cellebrite, or Google Chat source data into RSMF, it groups events into time blocks defined by the Slice by setting. See Short message conversion settings in the Processing profiles topic for details.

Splitting to meet RSMF file limits

Relativity splits a conversation into more files when it exceeds either of these limits, regardless of the Slice by value:

A maximum of 10,000 events per file, which is a Short Message Viewer condition.
A maximum size of 2 GB per file, which is a processing condition.

A conversation that is under the Slice by interval can still produce several documents for this reason.

Slicing after publish

Reviewers select individual events in the Short Message Viewer and save them as a new document. See RSMF slicing for more information.

The Slice by processing profile setting

Slice by determines how Relativity splits conversations into RSMF files by time. You configure it in the Short Message Conversion Settings section of the processing profile.

Slice by is required for RSMF conversion, and the profile layout marks it with an asterisk. Select a value whenever short message conversion is turned on.

Supported Slice by intervals

A slice begins with the first message and ends when the next interval boundary begins. You set the interval length with the Slice by value in the processing profile; the default is 24 hours. Slices do not extend past midnight.

Value	How Relativity groups events
4 hours	Messages are grouped into 4-hour intervals aligned to midnight. With a 4-hour interval, the boundaries are midnight, 4 AM, 8 AM, 12 PM, 4 PM, and 8 PM. For example: If the first message occurs at 5 PM, the slice ends at 8 PM. If the first message occurs at 11 PM, the slice ends at midnight.
8 hours	Messages are grouped into 8-hour intervals aligned to midnight. With a 8-hour interval, the boundaries are midnight, 8 AM, and 4 PM. For example: If the first message occurs at 7 AM, the slice ends at 8 AM. If the first message occurs at 5 PM, the slice ends at midnight.
12 hours	Messages are grouped into 12-hour intervals aligned to midnight. With a 12-hour interval, the boundaries are midnight and 12 PM. For example: If the first message occurs at 10 AM, the slice ends at 12 PM. If the first message occurs at 8 PM, the slice ends at midnight.
24 hours (default)	Messages are grouped into 24-hour slices, beginning at 00:00 on the calendar date that opens the slice. This is the default setting. If the Slice by value is empty, the time interval defaults to 24 hours.
1 week	Messages are grouped into 7-day slices, with Monday at 00:00 being the anchor. For example: If the first message occurs on Monday at 7 AM, the slice ends at 00:00 the following Monday. If the first message occurs on Friday at 5 PM, the slice ends at 00:00 the following Monday.

Time gaps in messages

Slices do not run continuously from the start of the conversation. Time gaps in message activity do not result in empty slices. A new slice begins only when the next message occurs.

For example:

A conversation contains messages on March 3, 2026 starting at 1:30 PM, further messages on the morning of March 4, 2026, then no activity until March 12, 2026. With Slice by set to 24 hours, Relativity produces three documents:

Slice	Window	Events included
1	March 3, 2026, 00:00 to 4 March, 2026, 00:00	Messages sent on March 3, 2026.
2	March 4, 2026, 00:00 to 5 March, 2026, 00:00	Messages sent on March 4, 2026.
3	March 12, 2026, 00:00 to 13 March, 2026, 00:00	Messages sent on March 12, 2026.

There are no slices for March 5, 2026 through March 11, 2026, because those dates do not contain messages. The 1:30 PM time stamp of the first message does not shift the ending slice boundary.

Time zone handling

Slicing uses the processing time zone and shifts slice boundaries to match it. Set Default time zone on the processing profile before you run the job.

The date range filter in the Short Message Viewer works differently. It displays timestamps in the time zone of the local machine, whichever time zone the processing profile uses. Account for the offset when you filter by date.

Orphaned messages

When slicing divides a conversation across time blocks, messages from one thread are stored in different documents. A message separated from its parent conversation becomes an orphan, and Relativity adds a note at the start of the message to identify it. Longer intervals produce fewer orphaned messages.

Changing slice boundaries after processing

It is possible to change slicing after processing by the following:

Reprocess with a different Slice by value

To change the Slice by value on processed files, update the value in the processing profile and run the job again.

Regenerate converted data after publish

To replace converted data that is already published, use the post-publish delete workflow to remove the published documents, then reprocess the source data with the interval you want. See Post-publish delete for more details.

Post-publish delete recalculates deduplication and evaluates documents individually rather than by processing set or data source. A document that belongs to a deduplication family shared with another data source is retained. Review the deduplication effects for your workspace before you start.

Slicing published documents

After documents are published, reviewers create slices in the Short Message Viewer by selecting events and saving them as a new document. The new document takes the control number of the original with _sliceXXX appended, and a banner in the Viewer links back to the original document.

For the full procedure, the permissions required, the fields a slice populates, and the audits slicing generates, see RSMF Slicing.

Two options on the Save as new document modal affect what the slice carries forward:

Copy Layout data—copies coding decisions saved on the selected layout to the slice. A field that is absent from the layout is not populated on the slice.
Preserve all participants—includes every participant from the original conversation in the metadata of the slice. When this option is turned off, the slice includes only the participants whose events you selected.

Slicing one document at a time

Reviewers slice documents individually. Relativity has no mass operation for slicing published documents, so a large volume of documents requires a separate operation for each one. For a conversation that spans a long date range, this takes considerable time.

Two options address this:

Set the interval during processing. Choosing a Slice by value that matches how you intend to review the data is faster than slicing documents individually after publish. Use this approach whenever you control the processing job.
Automate slicing through the API. The Short Message Viewer Manager services expose a slice method that accepts a list of event indexes, so a developer can script slicing across many documents. See Short Message Viewer Manager (REST).

Troubleshooting slice errors

The errors in this section are slice operation failures rather than configuration questions.

Error	Description
The slice exceeds the identifier field length	A slice control number consists of the original control number plus _sliceXXX, and attachments in a slice receive a further _XXX. When the resulting value is longer than the identifier field permits, the slice fails. Contact Relativity Support with the workspace name and the control number of the original document.
The slice fails on a layout field	Slicing copies fields from the layout you select in Copy Layout data. Slice the document without copying layout data to confirm whether a specific field causes the failure, then contact Relativity Support with the layout name.
A participant validation warning appears	When the participants in the RSMF email-style header differ from the participants in the manifest, Relativity records a validation warning. The warning does not stop processing or publishing.