Attachment limit properties
Summarize
Summary of Attachment limit properties
ServiceNow controls email attachment limits through configurable system properties that govern both inbound and outbound emails. These properties ensure attachment counts and sizes stay within manageable bounds to maintain system performance and email deliverability.
Show less
Key Properties
- glide.email.inbound.maxattachmentcount: Maximum number of attachments allowed per inbound email (default 30).
- glide.email.inbound.maxtotalattachmentsizebytes: Maximum total size in bytes for all inbound email attachments (default 18,874,368 bytes).
- glide.email.outbound.maxattachmentcount: Maximum number of attachments allowed per outbound email (default 30).
- glide.email.outbound.maxtotalattachmentsizebytes: Maximum total size in bytes for all outbound email attachments (default 18,874,368 bytes). This value should be set below the maximum email size due to encoding overhead.
Note: The property com.glide.attachment.maxsize overrides these limits by setting a maximum file size for any single attachment system-wide.
Inbound Email Attachment Processing
The system enforces attachment count and total size limits on inbound emails, discarding attachments that exceed configured thresholds. Discarded attachments are logged in the Email Attachments [sysemailattachment] table along with the discard reason, and remain recorded in the Email [sysemail] record.
The order of attachment processing affects which attachments are discarded and may vary per email. When discards occur, an event (inbound.emailattachments.discarded) is fired, which can trigger notifications to alert the sender.
Inbound attachments identical to existing attachments on the target record are prevented from attaching again.
Outbound Email Attachment Processing
Outbound emails are also subject to attachment count and size limits. Emails exceeding these limits generate warnings in the system log and send attachments only up to the configured maximums.
This applies to emails from various sources, including notifications, scheduled reports, and exported data:
- Notifications: If attachments exceed outbound limits, excess attachments are excluded and warnings logged.
- Scheduled Reports: Large reports exceeding limits are sent without attachments, with a log warning. Sending links to large reports is recommended instead.
- Exported Lists: When emailing exported records that exceed size limits, the email is sent without attachments and a warning is logged.
Practical Implications for ServiceNow Customers
By understanding and configuring these attachment limit properties, customers can manage email attachment handling efficiently, avoid performance issues, and ensure compliance with email size constraints. Monitoring system logs and leveraging discard events enables proactive communication with users when attachments are excluded or discarded.
Several properties control email attachment limits.
To see the status of all email attachments, go to the Email Attachments [sys_email_attachment] table.
Properties
All the properties are located in the System Property [sys_properties] table. Setting any of the following properties to an excessively large value may cause performance issues.
| Name | Description |
|---|---|
| glide.email.inbound.max_attachment_count | Sets the maximum number of attachments allowed per inbound email.
|
| glide.email.inbound.max_total_attachment_size_bytes | Sets the maximum total attachment size in bytes allowed per inbound email.
|
| glide.email.outbound.max_attachment_count | Sets the maximum number of attachments allowed per outbound email.
|
| glide.email.outbound.max_total_attachment_size_bytes | Sets the maximum total attachment size in bytes allowed per outbound email.
To send an email, the system must encode the contents of the email. This process
may significantly increase the size of the email, including any attachments. It is
best to set this property to a value well below the maximum email size.
|
Inbound email attachment processing
For inbound emails, the system enforces the maximum number and size of attachments as set by the glide.email.inbound.max_attachment_count and glide.email.inbound.max_total_attachment_size_bytes properties. When an attachment for an inbound email exceeds either value, the attachment is discarded. A record is created in the Email Attachments [sys_email_attachment] table containing the discarded file name and the reason it was discarded. The discarded file remains in the Email [sys_email] record. The order in which the system processes the attachments determines which attachments are discarded. This order may not be consistent from email to email.
When an inbound email attachment is discarded, the system also fires the inbound.email_attachments.discarded event. You can use the event to trigger a notification that alerts the email sender. For an example of a notification that can be triggered by the event, see the inactive "Demo Email Attachment(s) Discarded" notification.
Inbound email attachments are prevented from attaching to the target record if an identical attachment exists.
Outbound email attachment processing
For outbound emails, the system enforces the maximum number and size of attachments as set by the glide.email.outbound.max_attachment_count and glide.email.outbound.max_total_attachment_size_bytes properties. Email records are created from various sources and may exceed the configured attachment limits.
Emails that are ready to be sent from the Email [sys_email] table are subject to the outbound attachment limits. Emails that exceed either limit trigger a warning in the email system log and are sent with attachments up to the maximum number or total file size.
The log message for such an email might look like this: Maximum combined attachment size exceeded. (max:15728640 bytes). One or more attachment records ignored.
Emails for notifications, scheduled reports, and exported tables
Notifications can be set to include all the attachments from the record that triggers the notification. If the attachments exceed either of the outbound email attachment limits, the system excludes the excess attachments from the email and logs a warning message.
Reports can be scheduled for email distribution as attachments. Large reports may exceed the outbound attachment size limit. In this case, the system sends the scheduled report email without the report attached and logs a warning message. To avoid the issue, send links to large reports instead of sending the reports as attachments.
If a user attempts to export numerous records from a list that exceeds a configured warning threshold, a dialog box offers the option to email the exported records as an attachment. If the attachment exceeds the outbound attachment size limit, the system sends the email without the exported record list attached and logs a warning message.