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Unix Server Migration !

rharivenkatesh used Ask the Experts™
Hello Gurus,

All of you might have done tonnes of unix server and application migration.

Is there a checklist to follow on while doing the same?

Does any one have list of commands checklist as well for server migration?

Fo eg:

To check size of the filesystem
To check the DB volume and corresponding size.
To check file access permissions.

and so on.

I would like to have for AIX and Sun Solaris.

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Distinguished Expert 2017

The check list would usually do with seeing what the current requirements/usage of the current file system and based on that information you spec out what you would need for the newer one.

If you already have the new server, the check list basically to do what you can with what you got.


Hello Arnold,

I already have a checklist but not complete. This tells me what i need to look for and not to miss out. I was asking on that sense. The specifics of the environemnt goes out as extra ones. This is a generic one that we need to take care for any migration transfer.

what do you mean by migration?
from windows to unix?
from old version to new version?



From one unix to another unix server.

Distinguished Expert 2017

You have to make sure that any custom applications you have will work on the new one i.e. kernel changes, library changes etc. may require that you recompile the application on the new server.
Also making sure that what you use can work under the newer system.
Most Valuable Expert 2013
Top Expert 2013
some considerations -
- Users/groups - created? Same numerical IDs (e.g. when NFS is involved)? AIX - lsuser, lsgroup
- System environments - ulimit, max. processes per user? AIX - ulimit, lsattr -El sys0
- Filesystems - permissions?
- AIX (below. 6.1) - In case of a DB server - asynchronous I/O configured? AIX - lsdev -Cl aio0
- Again AIX - Network options (no), Virtual memory options (vmo - min/maxperm%), I/O options (ioo), maybe NFS (nfso) checked?
- inittab - all needed autostarts there (kernel extensions loaded, backup scheduler started, maybe monitoring agents started)? AIX - lsitab -a
- inetd subservers enabled/disabled? (telnet, ftp, rwho, rexec, shell etc.)? AIX - lssrc -ls inetd
- TCP/IP daemons - sendmail, xntpd ...?
- syslog configured? AIX - lssrc -ls syslogd
- OS version/patches, Firmware? AIX oslevel, lsmcode
- Network - VLAN, routing, firewall rules? Etherchannels, aliases, DNS entries? DHCP in use, configured? NIS? NFS?
- machine oriented software installed - sshd, maybe sudo, lsof etc.?
- All the usual rest - filesystem size, memory size, number of CPUs, (AIX LPAR- virtual processing units, capped/uncapped, weight)?
All the above, and then you're likely to have missed something else unless you have some bad-ass configuration management, change control, and tons of discipline.

In my experience, even the best planned migrations may encounter issues, however small. Ensure you (the royal you that is) have tested every aspect of the services you hope to run on host X before you go live, in the production environment before flicking the switch. If you have the resources, make sure that you have separate Dev, Test, QA and stress test environments set up (where necessary), and ensure that adequate QA (functional and regression tests). Sometimes, that might just be test you carry out. Sometimes, you'll have justification for including app support, test departments and customers.

So, capture your config, provision your new host (ensuring that the process is consistently repeatable), apply your changes required to prepare your environment, again capturing every single change and test. If you can, do it again following the process you've now documented - use VM technology if necessary. Then, create a roll back plan and test that too.

Come migration time, make sure you have all the necessary help/resources available. if you've done your homework, there should be few nasty surprises and in the absolute worse-case, you can roll back and try again.




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