Add README for Attachment Size Audit script

This README provides an overview of the Attachment Size Audit script, including its functionality, configuration, prerequisites, and use cases.

Author: NowSharif

Server-Side Components/Background Scripts/Attachment Size Audit/README.md

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+# Attachment Size Audit
+
+A ServiceNow background script that analyzes your instance's attachment storage and identifies which tables consume the most space and locate oversized files.
+
+## Overview
+
+This read-only script scans all attachments in your instance and provides:
+- Total storage used across all attachments
+- Storage breakdown by source table (kb_knowledge, sc_task, incident, etc.)
+- List of the 25 largest individual attachments
+
+The script does not modify or delete any data—it only reads and reports findings.
+
+## How It Works
+
+The script runs through three main steps:
+
+1. **Calculate Total Storage** - Sums all attachment sizes to give your total storage footprint
+2. **Break Down by Table** - Groups attachments by source table to identify which applications consume the most storage
+3. **Find Largest Files** - Identifies individual attachments larger than your threshold and lists them in descending order
+
+## Configuration
+
+Before running, adjust these variables at the top of the script:
+
+- `TOP_N_ATTACHMENTS` (default: 25) - Number of largest files to display
+- `MIN_SIZE_MB` (default: 5) - Only show attachments larger than this size in MB
+- `USE_COMPRESSED_SIZE` (default: true) - Use actual disk size (true) or logical file size (false)
+
+## Prerequisites
+
+- Admin role to execute background scripts
+- Global scope (or scoped app with sys_attachment visibility)
+- Read access to sys_attachment table
+- Access to System Logs to view results
+
+## How to Run
+
+1. Navigate to **System Definition → Scripts - Background**
+2. Click **New** and paste the script
+3. Optionally adjust configuration variables
+4. Click **Execute**
+5. View results in **System Diagnostics → System Log** (search for "Attachment Size Audit")
+
+## Sample Output
+
+```
+=== Attachment Size Audit Started ===
+Using size field: SIZE_COMPRESSED
+
+Total Attachment Storage: 415.28 MB
+
+=== Storage Usage by Table (Descending) ===
+invisible.sys_store_app           : 175.29 MB
+sys_upgrade_manifest              : 49.39 MB
+ZZ_YYsn_wn_media                  : 33.50 MB
+ZZ_YYdb_image                     : 28.99 MB
+sys_sg_mobile_builder_config      : 25.36 MB
+ZZ_YYhelp_content                 : 21.00 MB
+incident                          : 1.18 MB
+kb_knowledge                      : 75.54 KB
+
+=== Top 25 Largest Attachments (>5 MB) ===
+[ 68.47 MB ] sncencZZYY.fd254d9443a161100967247e6bb8f200_3_1_3.zip | Table: invisible.sys_store_app | Record: fd254d9443a161100967247e6bb8f200
+[ 24.72 MB ] upgrade_manifest.csv | Table: sys_upgrade_manifest | Record: d5ee366b47203210ca05a464116d4328
+[ 24.66 MB ] upgrade_manifest.csv | Table: sys_upgrade_manifest | Record: 9ee610ffe17a22108bb2327e625886d0
+[ 17.77 MB ] image | Table: ZZ_YYhelp_content | Record: 19d642e347203210ca05a464116d4369
+[ 11.63 MB ] sncencZZYY.a77e3ede4df92010f87774ecf02d44f3_28_1_1.zip | Table: invisible.sys_store_app | Record: a77e3ede4df92010f87774ecf02d44f3
+
+=== Attachment Size Audit Complete ===
+```
+
+## Use Cases
+
+- **Storage Planning** - Understand current attachment storage and plan for capacity growth
+- **Cost Optimization** - Identify storage hotspots for cloud instances to reduce costs
+- **Performance Issues** - Find large attachment tables that may be slowing queries
+- **Cleanup Strategy** - Identify which tables and files should be targeted for archival or deletion
+- **Pre-Upgrade Preparation** - Run before major upgrades to identify optimization opportunities
+
+## Future Enhancement Opportunities
+
+- **Generate Cleanup Script** - Create a companion script to delete old or orphaned attachments with DRY_RUN mode
+- **Orphaned Attachment Detection** - Identify attachments where parent records have been deleted
+- **File Age Analysis** - Track attachments older than 30/90/365 days to support retention policies
+- **File Type Breakdown** - Categorize attachments by extension (PDF, DOCX, MP4, etc.)
+- **Email Notifications** - Send automated summaries to storage admins with key metrics
+- **Dashboard Widget** - Create PA widget to visualize storage trends over time
+- **Scheduled Reporting** - Set up as scheduled job to track growth monthly
+- **Duplicate Detection** - Find duplicate attachments on same records for cleanup opportunities
+
+## Safety & Performance
+
+- **Read-only operation** - No data is modified or deleted
+- **No infinite loops** - Explicit limits on record processing
+- **Timeout prevention** - Efficient aggregate queries for large datasets
+- **Sub Pro Testing** - Test in sub-production environments first
+
+
+## Authors
+Masthan Sharif Shaik ( <a href="https://www.linkedin.com/in/nowsharif/" target="_blank">LinkedIn</a> ,  <a href="https://www.servicenow.com/community/user/viewprofilepage/user-id/668622" target="_blank">SN Community</a> )
+
+## Version History:
+* 0.1
+    * Initial Release