How to install Oracle Zero Downtime Migration (ZDM)
Oracle Zero Downtime Migration (ZDM) is a free to use software which allows you to automate your database migrations to OCI, multicloud and onprem systems
some Prerequisites
It's highly recommended to have a dedicated host for the ZDM installation.
The host must match the following prerequisites:
100GB of free space
Oracle Linux 8, Oracle Linux 9 or Redhat 8
network access to both, source and target database nodes
(I was using an AWS EC2 instance)
ZDM installation
create group and user
## as root
groupadd zdm -g 1001
useradd zdm -g 1001
install necessary OS packages
### as root
yum install glibc-devel expect libaio linsl
adapt /etc/hosts if needed
make sure your hostname is resolvable (especially on cloud instances this might be not working out of the box)
this step is crucial as the ZDM service won't start without proper hostname resolution
the simple check is to ping your hostname
create the install dirs (as zdm user)
## run as zdm user
mkdir -p /u00/app/oracle/zdmhome /u00/app/oracle/zdmbase
optional - set env vars (as zdm user)
## as zdm users
export ZDM_HOME=/u00/app/oracle/zdmhome
export ZDH_BASE=/u00/app/oracle/zdmbase
create a stage directory
mkdir $HOME/stage
choose any dir which fits your env the most
download the software from edelivery
Download ZDM here:
https://www.oracle.com/database/technologies/rac/zdm-downloads.html#
I've used the wget script from edelivery cause it's the easiest way as you just need to copy the wget.sh and create an auth token.
afterwords execute the script enter your token and wait for the download to complete.
the other option is to download the software manually to your system and copy to the ZDM host.
wget.sh
should end with the the following zip file
ls -lth V1055491-01.zip
-rw-rw-r--. 1 zdm zdm 1.1G Apr 14 17:47 V1055491-01.zip
extract the zip
unzip V1055491-01.zip
this will give us
ll
total 1099308
-rw-rw-r--. 1 zdm zdm 1125684981 Apr 14 17:47 V1055491-01.zip
-rwxr-xr-x. 1 zdm zdm 2509 Jun 17 09:15 wget.sh
drwx------. 4 zdm zdm 179 Apr 11 17:14 zdm26.1
now we're all set to install zdm on our host
install zdm with
the installation is quite straigh forward
cd zdm26.1
./zdminstall.sh setup oraclehome=/u00/app/oracle/zdmhome oraclebase=/u00/app/oracle/zdmbase ziploc=/home/zdm/stage/zdm26.1/zdm_home.zip
ZDM kit home: /home/zdm/stage/zdm26.1
/home/zdm/stage/zdm26.1
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Validating zip file...
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25 04-11-2026 17:13 rhp/zdm.build
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Unzipping shiphome to home...
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Unzipping shiphome...
Shiphome unzipped successfully..
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##### Performing GridHome Software Only Installation #####
[...]
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Adding Certs to ZDM
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Adding Certs to ZDM
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Adding java jre to ZDM
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ZDM service setup finished successfully...
Validate the installation
$ZDM_HOME/bin/zdmservice status
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Service Status
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Running: true
Tranferport:
Conn String: jdbc:derby:/u00/app/oracle/zdmbase/derbyRepo;create=true
Repo Path: /u00/app/oracle/zdmbase/derbyRepo
RMI port: 8897
HTTP port: 8898
SSH port: 22
Wallet path: /u00/app/oracle/zdmbase/crsdata/i-xxx/security
$ZDM_HOME/bin/zdmcli -build
full version: "26.1.0"
patch version: ""
label date: 260410.1
ZDM kit build date: Apr 11 2026 17:13:53 UTC
CPAT build version: 26.3.0
create ssh keys
ZDM relies on ssh passwordless connections to source and target. therefore it's crucial to create the key pair accordingly (if you don't have the already in place)
use the following to create a keypair if needed
ssh-keygen -m PEM -t rsa
copy the keys afterwards to the source and target system
ssh-copy-id -i ~/.ssh/id_rsa user@host
Conclusion
Installation of ZDM is pretty straight forward.
Important: Make sure your system has proper name resolution in place! (your hostname should resolve to an proper IP!) if hostname resolution fails zdm will fail to start.
Stay tuned for the next post around ZDM where we see how to configure ZDM to migrate Oracle databases.
Docs/Further reading
Download Link
https://www.oracle.com/database/technologies/rac/zdm-downloads.html#
Docs
Oracle Blog
https://blogs.oracle.com/maa/announcing-oracle-zero-downtime-migration-26-1
