Comments on: Backup

By: tedsoh

tedsoh — Fri, 20 Jul 2012 15:43:52 +0000

Hi thanks for all advice.I think the only choice is to discuss with user to schedule a best time for both parties.Thanks

By: MDratwa

MDratwa — Wed, 18 Jul 2012 15:01:25 +0000

One other thing should be considered is that a reboot run a complete set of diag on all hardware at one time. Diags are run (on different hardware pieces) at different times. Unprotected storage is condensed to the system values (before rebooting – check system values to the current values (in WRKSYSSTS screen) in case some of the values need changes). It is also good to run “RLCSTG” (once a year or two) to fix damage objects and reclaim any possible broken chains in deleted disk files. As good as the AS400 is, some maintenance has to be done and users have to understand that (use the idea of their car needing maintenance). Try to set up a time (like a holiday or plant shut down) when the smallest number of users would be affected.

By: TomLiotta

TomLiotta — Wed, 18 Jul 2012 01:41:36 +0000

The AS400 caches most of it’s transactions while it’s running and only writes those transactions to disk during an IPL or full system backup.

While much can be cached (if cache is large), it’s definitely not true that caches aren’t written to disk until “IPL or full system backup”. Since full system backups might only be done once a year or less frequently, and many busy systems go six months and more between IPLs, the cost of that much cache would be astronomical. Writes from cache to disk happen whenever a disk isn’t otherwise busy, essentially as with all disk/cache hardware.

A power failure shouldn’t lose any data at all except perhaps data in memory buffers that haven’t been sent back out to disk yet (i.e., out to disk cache). Disk cache generally should be battery-protected so power loss of reasonable duration shouldn’t be a problem.

Tom

By: tedsoh

tedsoh — Wed, 18 Jul 2012 00:37:16 +0000

Morning Guys,
The requirement is quite simple.
Our operation would normally do a full system backup every month.
During this time, they will also try to perform some maintenance like PTF, UPS maintenance, etc. The system will not be available for about 4 to 5 hrs.
In the previous time, the operation are able to do that as they had not implemented the 24/7 monitoring system on the production.

I believe that this issue can be resolve by having a discussion with those user to come out wth a schedule for the down time for maintenance and backup.
BUT i think my Boss had piss them off for too many reason and now that they are making things difficult. (User had indicated that if the IT dept can find a solution and not to affect their operation, they can perform their Backup and Maintenance anytime).
I am just trying to help my operation staff to se if there are any other option available.

By: mshen

mshen — Tue, 17 Jul 2012 23:54:28 +0000

The AS400 caches most of it’s transactions while it’s running and only writes those transactions to disk during an IPL or full system backup. If the system were to hard fail due to a power outage, you would loose massive amounts of data. A full system backup will require you to end all subsystems as well, so it’s best to work out a maintenance schedule so you make make sure you can restore the system in the event of a disaster.

By: TomLiotta

TomLiotta — Tue, 17 Jul 2012 05:47:18 +0000

We would like to shut down the system for some maintenance…

You say “maintenance”, but you also mention “backup”. For “maintenance”, only a mirror system will do, even for a small group as long as 24/7 is a real requirement. If it’s a business requirement, your boss has no choice.

Now, it might be that your ‘development’ system could be appropriate. It’s hard to say from here. Replication and fail-over could be set up to handle the 24/7 requirement. It’d possibly be relatively easy if only a portion of your application suite is involved.

But if there is no actual 24/7 requirement, then your “small group of users” have to be prepared for maintenance. It’s a fundamental fact of systems that maintenance requires disconnection of service at times. You can’t do operating system maintenance will the system is providing services.

By replicating required tables, programs, users, or whatever objects are needed to a secondary system, those users could have essentially the same access with no visible difference. Any changes would need to be synchronized back to the main system when it’s available again, but it can be done.

Now, if it’s not “maintenance” but only “backup”, the only issues should be with data objects that are actively in use at the times a backup process runs. But there are ways of handling that without requiring service interruptions. Even if a file can’t be backed up due to application locks, it can almost always be copied, to a second library or a second system. Once done, the copy can be backed up. Other methods can be used to handle just about any object for special circumstances.

In general, backups can be handled in one way or another for nearly all cases. But “maintenance” can have absolute requirements.

So the question back to you is about exactly what you need to handle. If it’s backups, then describe the objects that are involved. What are the object types? For files, how many of them, how large and how many rows? How often are exclusive locks placed on data? What is a basic activity schedule? Usually, activity rises and falls over hours of the day and/or days of the week.

What can you tell us?

Tom

By: tedsoh

tedsoh — Mon, 16 Jul 2012 14:20:21 +0000

Hi,Normally we will do a system backup and then do some maintenance like UPS servicing, etc.In the pass, we would try to arrange a off day to do this kind of activities.But recently, our production dept implemented a production monitoring system that keep track of all the process in the manufacturing line. By the way, they are running 24/7.Mirroring is out of the question as it is too costly.One of our staff is suggesting to create some PC program for them to operated while the system is down and update the data back to the AS400 when it is up.I do not think it is a good idea, but i had run out of idea.Any advice ?Thanks in advance.They are not willing to accept the downtime of 3 – 4 hrs that we required.Now

By: CharlieBrowne

CharlieBrowne — Mon, 16 Jul 2012 12:24:29 +0000

Can you clarify what is it you want to do?Yow say you want to do maintenance and then you ask about backup. I have to assume the maintenance you want to do is not to backup your system.How are you backing up right now?What is the maintenance you want to do?