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Migrating from MailStore#

This documentation applies to Piler enterprise edition 2.1.0

Revision #1

Publication date: 2025-DEC-12

Overview#

MailStore Server (now owned by OpenText) provides a straightforward export-to-filesystem feature that outputs emails in EML format. This guide walks you through exporting from MailStore and importing into Piler.

Prerequisites#

  • MailStore Server administrator access
  • Sufficient disk space for export (roughly equal to your archive size)
  • Network or USB storage for transferring data to Piler server

Step 1: Export from MailStore#

Open MailStore Client#

  1. Launch MailStore Client and connect to your MailStore Server
  2. Log in with an administrator account
  1. In the navigation pane, expand Administrative Tools
  2. Click Export E-mail
  3. Select Export E-mail to File System

Configure Export Settings#

  1. Source: Select the archives to export
  2. Choose "All Users" for complete migration

  3. Or select specific users/archives as needed

  4. Target Folder: Choose the export destination

  5. Use a network share or local drive with sufficient space

  6. Example: \\fileserver\mailstore-export\ or D:\mailstore-export\

  7. File Format: Select EML (RFC 822)

  8. This is the standard email format Piler accepts

  9. Options:

  10. Enable Retain folder structure (optional, helps organization)
  11. Enable Export signed if you want integrity verification

  12. Set date range filters if doing partial migration

  13. Click Next and then Finish to start the export

Monitor Export Progress#

  • MailStore displays progress during export
  • Large archives (millions of emails) may take several hours
  • Export speed depends on disk I/O and archive size

Step 2: Transfer to Piler Server#

If Piler server can access the export location directly:

# Mount network share on Piler server
mount -t cifs //fileserver/mailstore-export /mnt/import -o username=user,password=pass

# Or use NFS if available
mount -t nfs fileserver:/export/mailstore /mnt/import

Option B: rsync (Remote transfer with resume support)#

# From the machine with exported files
rsync -avz --progress /path/to/mailstore-export/ piler-server:/var/piler/import/

# Resume interrupted transfer
rsync -avz --progress --partial /path/to/mailstore-export/ piler-server:/var/piler/import/

Option C: Physical Media#

For multi-TB archives, USB drives are often fastest:

  1. Copy export to USB drive
  2. Connect USB to Piler server
  3. Mount and import directly

Step 3: Import into Piler#

Set Permissions#

chown -R piler:piler /var/piler/import/

Run Import#

Basic import:

pilerimport -dir /var/piler/import/mailstore-export -tenantid fictive -workers 8 -progress

For large archives (recommended settings):

pilerimport -dir /var/piler/import/mailstore-export \
  -tenantid fictive \
  -workers 16 \
  -progress

Import with automatic cleanup:

pilerimport -dir /var/piler/import/mailstore-export \
  -tenantid fictive \
  -workers 8 \
  -progress \
  -remove

Monitor Progress#

The -progress flag shows:

  • Files processed / total
  • Success, duplicate, and failed counts
  • Estimated time remaining

Step 4: Verify Migration#

Check Statistics#

After import completes, review the summary:

Import completed:
  Processed:  1,234,567
  Success:    1,200,000
  Duplicates:    30,000
  Failed:         4,567
  Excluded:           0

Verify in Piler UI#

  1. Log into Piler web interface
  2. Search for emails from different time periods
  3. Verify attachments are accessible
  4. Check that all expected mailboxes appear

Investigate Failures#

If files failed to import:

  • Check file permissions
  • Look for corrupted EML files
  • Review Piler logs:

docker logs piler 2>&1 | grep -i error

or

journalctl -xeu piler | grep -i error

Troubleshooting#

"Permission denied" errors#

chown -R piler:piler /var/piler/import/
chmod -R 644 /var/piler/import/*.eml

Slow import performance#

  • Increase workers: -workers 16 or -workers 32
  • Use SSD storage for import directory
  • Ensure database has adequate resources

High duplicate count#

This is normal if:

  • MailStore archived the same email multiple times
  • Multiple users received the same email (expected behavior)

Piler deduplicates automatically - duplicates don't consume extra storage.

Missing emails after import#

  1. Verify export completed fully in MailStore
  2. Check for files that failed to import
  3. Re-run import (already-imported files are skipped)

Cleanup#

After verifying successful migration:

# Remove imported files (if not using -remove flag)
rm -rf /var/piler/import/mailstore-export/

# Unmount network share if used
umount /mnt/import

Reference#