3.1. What was migrated?
The following items were migrated from Herald/Webmail:
-
Email data from Herald IMAP mailstore
-
Contacts from Webmail
-
Preferred Sender from Webmail (if this was an Oxford address associated
with the user)
-
Signature from Webmail
-
Quota (if >2GB, otherwise was set to 2GB)
-
Vacation Message/Setting
-
Forwarding Addresses
-
Whitelist/Blacklist
-
Move to Junk Mail SPAM setting (see below)
The following items didn’t get migrated:
3.2. How did the SPAM setting map across?
Nexus has SPAM filter settings of Low, Medium, High and Off, which mapped to a
Herald equivalent of >7, >5, >3, and 0 respectively. The value from
Herald was mapped across as per below:
0 -> Off
1 -> High(>3)
2 -> High(>3)
3 -> High(>3)
4 -> Medium(>5)
5 -> Medium(>5)
6 -> Medium(>5)
7 -> Low(>7)
8 -> Low(>7)
9 -> Low(>7)
10 -> Low(>7)
>10 -> Off
The ‘automatically delete SPAM over a certain threshold’ setting was not
migrated to Nexus.
3.3. How did the items get migrated?
Various techniques were used to push items from Herald to Nexus, all data was
encrypted in transit via HTTPS or SSL secured IMAP.
-
Email - IMAP to Exchange Webs Services conversion
-
Contacts - Exchange Webs Services
-
Preferred Sender - HTTPS to powershell
-
Signature - Screenscape OWA Light
-
Quota - HTTPS to powershell
-
Vacation Message/Setting - Exchange Webs Services
-
Forwarding Addresses - HTTPS to powershell
-
Whitelist/Blacklist - Screenscape OWA Light
-
SPAM settings - HTTPS to powershell
-
Corrupt messages found during the migration process
Some messages couldn’t be migrated as some element of their MIME structure was
corrupt, or they couldn’t be stored in Exchange for some other reason. When a
corrupt message was detected its subject was logged (and only the subject was
logged). At the end of the migration process, the system walked the Herald
mailbox and located all messages with subject lines that matched known corrupt
messages. All those messages were bundled in one or more zip files. The
majority of the messages in the zip file would have actually been in the
Exchange datastore, but because only the subject of the corrupt message was
logged we were unable to determine which message on Herald with that subject
was the corrupt one, and thus we had to place all messages into the zip file.
This ensured no data was lost during the migration process and left it down to
the end-user's software to try to figure out the content. Some clients were
more tolerant of these corrupt messages than others, but all would display an
approximation of the "true" intended message.
For some, the corrupt messages email/attachment were confusing and generated
support requests, but this was the best we could do when moving the email
between these different systems.
We found a particular issue with files which had a mime type of
application/applefile. A number of corrupt messages we saw had files of other
types marked as applefile and this caused issues. If a user receivedan email
with their corrupt messages in it or an email saying their migration was
stopped due to the number of corrupt messages, we recommended searching for
attachments with that mime type first as they were usually the cause of the
problem.
We also found that the zip files we produced would not open on some Mac
machines, although they were fine on Windows, Linux/UNIX and other Macs. If the
zip file appeared corrupt when opening on a Mac, we advised opening it on
another machine, preferably a PC.
3.4. Error Codes in the Migration Picker
If an account failed to migrate it was marked the next morning (circa 9am) in
the migration picker. For each failed account, a failure code was available.
Codes were added/removed as issues were found and solved. The last used codes
are listed below with an explanation for each.
| Code | Explanation | Response |
|---|
| Non-Herald Routing |
This user didn’t route their main email address to Herald. |
None |
| ForwardAddress=PreferredAddress |
The forwarding address on Herald was the same as the address used by
the Herald account to send email - not supported on Nexus |
Change forwarding on Webmail prior to re-migration |
| ForwardAddress=HeraldAddress |
The forwarding address on Herald was set to username@herald.ox.ac.uk -
this is not supported on Nexus |
Change forwarding on Webmail prior to re-migration |
| ForwardAddress=NexusAddress |
The forwarding address on Herald was set to username@nexus.ox.ac.uk -
this is not supported on Nexus |
Change forwarding on Webmail prior to re-migration |
| Early Failure - Unknown |
An error occurred early in the migration process. This usually
occurred when the migration system was under too much load. |
OUCS will investigate and schedule re-migration |
| Case |
Two folders with the same name but different case were found (for
example, Sent and sent) |
Change folder names |
| Quotes |
One or more folders with double quotes in their name were found |
Change folder names |
| Slash |
One or more folders with trailing slashes in their name were found |
Change folder names |
| Clash |
One or more folders with reserved names that could not be remapped to
foldername_Herald, as foldername_Herald already exists, were found |
Change folder names |
| Folder Select StartIndex |
A problem was found opening a folder on Herald - a folder rename is
required |
Change folder names on OUCS advice |
| Mig-Failed Folder Read(1) |
A problem was found opening a folder on Herald/creating a folder on
Nexus |
OUCS will investigate and schedule re-migration |
| Mig-Failed Folder Read(2) |
A problem was found opening a folder on Herald/creating a folder on
Nexus |
OUCS will investigate and schedule re-migration |
| Mig-Failed Exch Folder Create |
A problem was found creating a folder on Nexus |
OUCS will investigate and schedule re-migration |
| Mig-Slash |
One or more folders with trailing slashes in their name were found |
Change folder names |
| EWS-Error |
A system error occurred during migration. A cached copy of the old
user object prior to the mailbox being added stopped the migration tool
accessing the true mailbox. This was more likely to occur at the start of
the migration window. |
OUCS will investigate and schedule re-migration |
| Mig-Unknown |
A system error occurred during migration |
OUCS will investigate and schedule re-migration |
| Mig-Transporter |
A system error occurred during migration |
OUCS will investigate and schedule re-migration |
| Mig-Transporter PS |
A system error occurred during migration |
OUCS will investigate and schedule re-migration |
| Mig-Transporter(Died) |
A system error occurred during migration |
OUCS will investigate and schedule re-migration |
| Forward Corrupt |
A number of corrupt messages were found that could not be migrated.
There were either too many messages or they were too large to bundle into
a zip file and forward on |
Examine messages with subject lines as per personal failure email.
Remove messages where possible and contact OUCS to re-schedule migration
|
| Large Msg in Mailbox |
A number of corrupt messages were found that could not be migrated.
One or more of these were too large to bundle into a zip file and forward
on |
Examine messages with subject lines as per personal failure email.
Remove messages where possible and contact OUCS to re-schedule migration
|
| (no code) |
Ran out of time to migrate account or the account was disabled |
OUCS will re-schedule migration, most likely to a Sunday in the next
couple of weeks. OUCS will contact all users informing them of the new
migration date. |
NB: The owner of the account being migrated should have got a message detailing
what they needed to do or a generic "Unknown Error" message.
