Editing Training 2022 Linux team/ (section)

==Training session on Zimbra8 6 OS centos6 to zimbra8 8 15 RHEL8 migration session1 30 March 2023 - Tetra Support Staff - Biswajit Banerjee==

{{#ev:youtube|Yw3IeDcHiGw|640}}

'''Video summary:''' "Zimbra8 6 OS centos6 to zimbra8 8 15 RHEL8 migration session1" -- a detailed walkthrough of migrating a Zimbra 8.6 Open Source instance on CentOS 6 to Zimbra Network Edition 8.8.15 on RHEL 8, following Zimbra's official migration documentation closely (explicitly flagged as important since rsync binaries are OS-version-specific -- reusing binaries built for the wrong OS release will break things). Covers the documented flow: confirm backups exist first; on the old server, take an LDAP dump (`slapcat`-equivalent), back up mail/message data, and export it; provision a brand-new target server (rather than in-place upgrading) and run the appropriate Zimbra install/restore process there. Walks through setting the new server's admin/LDAP/MySQL passwords to match the old server's -- pulled directly from the old server's `localconfig.xml`, since matching credentials are required for the LDAP data restore to work. Details the LDAP import itself: stop Zimbra on the new server, back up the existing empty LDAP directory, then import only the actual database content (explicitly skipping config and access-log databases as unnecessary for this migration, unlike a master/master replication setup which would need them) using the previously-exported LDAP dump file, followed by an `ldap-config`/reindex-equivalent structural rebuild step that must exactly match between old and new (any mismatch causes problems) -- this rebuild step being the most time-consuming part of the whole process. Covers the actual mail-data transfer approach: rsync the full mailstore/index directories from old to new server, timing a couple of incremental rsync passes first to estimate how long a final sync will take (recommending doubling the observed time as a safety margin when scheduling the actual cutover window, since some additional work is always needed beyond the raw sync). Also covers practical field-support realities: confirming with the trainee whether remote access to the target site is available before the actual cutover, since at least one deployment location has no internet connectivity requiring physical presence. Session closes previewing the next topics -- building a Zimbra cluster and the incremental upgrade path (8.6 to 8.7 first, not straight to 8.8, since intermediate hops are required) -- promising the recording will be shared afterward as a reference alongside hands-on practice.