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Re: Intermittent backup



fixed

Hi Dave

What do you want the backups for ? How accurate do your backups have to be ? What constitutes a backup (I.e. you can recover to a point in time using a daily save and applying journal receivers) ? Is timeliness of recovery important ? Data only ?

Most likely the answers to these question will dictate what solutions are viable.

It does seem to me that something based on remote journaling protects your data by storing it at another site.You can easily apply journal entries to the last save to get you a point in time recovery rather than saving libraries at particular points in time. Remote journaling mostly saves you having to save the receivers to tape or transmit them offsite.

I guess it would be possible to achieve the same effect by using triggers and writing a record to a data queue each time something happened and sending that to the other system. Bu then you need to make sure all files are covered, deletes, commitment control etc. It seems to me it gets pretty hard pretty quickly and the viability depends on what you are trying to achieve.

In terms of doing backups to a remote machine using SAVRST*, as far as I recall, save while active can be something of a flawed solution. Partly it depends on what sync-ing the libraries you are saving require and whether you can successfully save all the libraries/objects to the *same* point in time. Having a master file that's missing transactions or vice versa would be a worry... At one point it was recommended that you shut your applications down to get a reliable sync point. V5R may have improved this but you'll need to check. In any event, I'm almost certain you need journaling and commitment control for this to work reliably anyway, so if disk cost or journaling performance myths were or issue your are back to where you started.

The other thing to consider is that you may have a huge burst of data over the wire when you do your save - and keep in mind that you have no save until that transmission completes successfully. You may even compromise the integrity of the remote library as well unless you keep a backup copy as a safety measure while you do your save). Remote journaling will keep you up to date the whole time but utilize the wire more effectively. You may still have some work to do to remove transactions depending on your use of commitment control

I noticed a product the other day called RAP/400 that seemed aimed at data replication only and was priced pretty low. I know nothing about it but it might be more what you are after. Having said that most of the HA Vendors have a low end product aimed at data replication or low end HA - iTera even has one that allows you "vault" your journals to a remote PC, which I thought was a cool alternative to HA.

Hope this helps

Regards
Evan Harris

At 12:36 a.m. 24/04/2007, you wrote:

I am looking for a way to "backup" or make copies of files and
libraries, without knocking people out of the system or slowing them
down to do so. I need a way to periodically backup up transaction files
or updated master files periodically throughout the day and send them to
an alternate box. HA software is not an option at this point. I know I
could use journaling but do not know that I want to go down that road,
or else I will push for the HA software.



Can I use CPYLIB, CPYF, CRTDUPOBJ, SAVOBJ, SAVLIB commands and achieve
the results I am looking for? I realize I might have to run them
multiple times throughout the day.



Thanks for the direction.



Dave





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