View Full Version : Mirroring
01-01-1995, 02:00 AM
I would like to get some feedback on mirroring AS400's. Are there any big concerns? If you trash your data does it in turn trash the mirrored Data base? How was the cut over to the backup when trouble hit? has one system maxed out the other? Any feeback would be excellent. Thanks
06-03-1999, 11:23 AM
On Thursday, June 03, 1999, 08:42 AM, ho ping wrote: I would like to get some feedback on mirroring AS400's. Are there any big concerns? If you trash your data does it in turn trash the mirrored Data base? How was the cut over to the backup when trouble hit? has one system maxed out the other? Any feeback would be excellent. Thanks <hr> I would have to ask if you are referring to IBM Bus level mirroring. If you are then you are correct, corrupting your DB will happen on both drives if it is an application error that causes this. Now if you have a hardware crash on a disk drive, bus level mirroring will protect you. The secondary drive will be available till the primary is repaired or replaced. If you are referring to some sort of data replication software, such as MIMIX or DATAMIRROR, then yes the corruption will be carried over depending on the setup of the product. <A > HREF="mailto:Jeff_Importico@Vanguard.com">(Jeff_Importico@Vanguard)</A>
06-03-1999, 05:25 PM
<font color blue>On Thursday, June 03, 1999, 08:42 AM, ho ping wrote: I would like to get some feedback on mirroring AS400's. <ul> Are there any big concerns? </font> Obviously additional hardware and software costs. Network bandwidth can be a very limiting factor. Over night in heavy batch processing some of the applications generate a lot of traffic. For us the result is there can be a 2+ hour difference between the two systems. If you are planning to use a third party product for the mirroring I would take the time to chose the vendor (Our experiences with the vendor we use have not lived up to expectations.) You need people and management focused on getting it working and tested. In my opinion it takes more time and attention then it really deserves. <font color > = blue> If you trash your data does it in turn trash the mirrored Data base? </font> I presume youre refering to a logical trash (rogue program or someone doing CLRPFM). Yes you have two copies of wrong data - but the files are consistent :). But I dont know if you would want to invoke a system swap because of trashed data (i.e. it us takes approx 1 hour to perform a controlled switch) I would be relying more on journals and backups to recover from this problem. <font color blue> How was the cut over to the backup when trouble hit? </font> So far we havent needed to cut over when trouble hit. Our switches have been planned (hardware upgrades, software upgrades, testing). It took a number of planning sessions and about 3 runs to get it right from ensuring everything switched across. I will think you'll find the AS/400 database side quite easy its more of the other issues such as network redirection. Currently our biggest concern is a system down during end of day processing.... Getting the system switched over and the batch restarted from a logical and correct point is an outstanding issue - as of today we would need to restore some files on the backup system and then restart the end of day from the beginning - this is not acceptable at this site. <font > color = blue> has one system maxed out the other? </font> Yes, the primary production system is approx 2x the size in processing capacity of the backup system. But this is just a money saving issue - the backup has sufficient capacity for online operations - but end of day batch run time would be longer. [/list] HTH David
06-07-1999, 02:34 PM
Very timely for me. Thanks for the Info guys.
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