Upgade AIX 5.2 to 5.3 - PowerPath 4.2 to 5.1

Hi Brad,

I'm not an AIX guru so I can't advise on that side of things. However, if you do build a new pristine 5.3 environment with the same number & size of DMX volumes you could then make use of clones to take a copy the 5.2 vgs over to the 5.3 environment and test the host and application running in its own isolated lan. This way you can test during the day and since its a copy of production data, it doesn't matter if things go wrong. You can also re-establish the clone to get a new copy of production.

When you're ready to do the actual migration you'd shut down production & do a final incremental clone establish to get the latest data, and then cut over to the new box.

Clones are great for this sort of thing. More power to the storage!

Marc

Not an AIX guru either but plenty of SA experience in prior lives. My suggestion on deciding between upgrade vs new system. Personally I always leaned towards pristine system because if documented correctly and setup ahead of time you can really migrate in a short time window UNLESS the following are true:

1) You do not have good application support or unsure of any hooks the application may have put into the OS. (i.e. if you can not ensure progress is installed in the new environment and configuration files are OK)

2) If you do not have good system documentation or history. Sometimes throwing away old settings is great, but if you happen to through away some obscure NFS or FTP setup that you did not realize existed you could cause application outages.

Make sure your software versions support your new OS target. Ideally you get up to the target level that does support the OS prior to upgrading/moving to the OS.

Are the OS disk on the SAN? If so you could at least have a very quick back-out plan leveraging Timefinder Mirror or Clone copies to protect your OS.

Talking with some AIX support folks 5.2 > 5.3 does not seem like a major upgrade, but it will take time and is subject to upgrade irregularities like anything else.

One last suggestion. Any chance you can clonse this environment and put into an isolated LPAR? This would let you run through the upgrade and get a true feel for timing/issues that might arise at least going through the process?

I've been on vacation so I have been away from email. Thanks for all the suggestions and I will look closely at each one. I did forget to mention that during this 5.3 upgrade we will also upgrade the Progress database from version 9 to 10. Some other components may also be upgraded. The system is made up of many file systems and AIX volume groups.

Currently the OS disks (rootvg) and extra paging space are the only disks that are not on the DMX. Rootvg is mirrored on two IBM internal disks and the additional paging space is mirrored on another pair of IBM internal disks.

Creating a new LPAR is possible but I will likely need to add more RAM and CPU's to the p670 frame.

To date we have not done any clonning or mirroring with EMC technology but we need to move in that direction. Currently we have used the AIX command mirrorvg to migrate data from one array to the other. Once all data was moved to the new arrray we used AIX unmirrovg and reducevg to remove the volumes from the old array.

One more question about snap/clone as I am new to time finder.

For the new AIX 5.3 LPAR, I will create all the new sym devices, metas AIX Volume Groups and file systems so they will match exactly with the current production 5.2 LPAR.

I will then snap/clone the production volumes to the new 5.3 LPAR volumes. Throughout our testing of the new 5.3 environment I can re-snap/clone from the production 5.2 environment to the new 5.3 environment as often as neccessary. The night of cutover we will do one last snap/clone before making DNS changes to point our application to the new 5.3 LPAR.

During testing can I snap/clone from 5.2 to 5.3 without impacting 5.2 production? I'm hoping I don't need to unmount file systems on 5.2 production before the snap/clone operation. Also, is snap, clone or mirror better for this scenario (why)?

Thanks again - Brad

During testing can I snap/clone from 5.2 to 5.3 without impacting 5.2 production? I'm hoping I don't need to unmount file systems on 5.2 production before the snap/clone operation

Only the target need to be in dismounted/exported state no the source..if we are taking the PROD offlline then what is the importnace of these expensive tools ..

First, it is a good and smart plan prepare a Lpar with new OS and target version EMC software installed.
Second, when cut over, you should umount FS/varyoffvg, no need exportvg(for easy back to old system in case there are problems), while use symmask assign those volumes to new Lpar, configure those volumes and do importvg. After VG imported, you will see those Filesystems. If there are LVs used by database as raw device, you need change their permission according to old production system.
If you still have other concern and want to ask, pls send email to li_danny@emc.com

I'd recommend that you do a consistent split when you snap or clone but there is no need to take the devices offline for testing.

If you make snaps or clones prior to the actual implementation you should try and unmount or have the OS either down or as close to down as possible to make any potential roll back as smooth as possible.

Thanks for the good info. Let's say that we are going to cutover to the new 5.3 LPAR on a Saturday. On Saturday I will unmount/varyoffvg the current 5.2 production before the final snap/clone to the new 5.3 LPAR. But before that I would like to create these snap/clones on Monday then again on Tuesday then again on Wednesday so that we can get fresh data into our new 5.3 system for testing. Can I take the test snap/clones during the day without unmount/varyoffvg of the production 5.2?

Also, do you think I should use snaps or clones? Why is one better than the other for this situation?

you can, but keep in mind that will give you a crash-consistent copy of your production file system/application, as if somebody pushed the power button on you production box. So when you bring the file system online on the LPAR ..you might have to run fsck and do some kind of database recovery.



If this were my system , i would only use clones because i would not want to impact my production in any way by running tests on SNAP volumes that are simply pointers to my production volumes while clones are another physical copy of your data (depends on options selected during clone pair creation).

You can also look at the AIX feature "alt disk install" it allows you to copy your current OS to another drive, upgrade the OS on primary drive. If there are problems you just reboot from the orignal OS and its business as usual. Just a thought.