- how does asbackup ensure consistent of backup ,when server is running ?
- when i run for an Incremental backup ,by using ‘last-update-time’ option , could i know the exactly endtime of the backup ? , so next time i can backup after this timepoint ,as the incremental backup
This depends on your definition of consistent. By default asbackup will use the ‘scan’ method, which will slowly crawl through all the records in the namespace. As it finds a record, it will be recorded into the backup file. If using a ‘last-update-time’ option it will also check against the metadata stored in primary index. However, this backup is not a snapshot/consistent backup in many ways… Since it is a kind of ‘top-down’ approach and there is no forward log recovery concept, or quiesce, the records may change holistically as you do the backup… Ex… if record#1 is at the top and backup is done, you continue on your backup - but then as your application makes changes it will not be backed up again. So if your application changes record#300000 and also record#1 after the record#1 was backed up - it could be said that these records are now ‘out of sync’. It’s like taking a panoramic picture where there is a cut off arm somewhere, if I had to make an analogy. It is a difficult problem to solve within the Aerospike world indeed
Your endtime of the backup can be recorded in your script… but you should assume that you may need to re-backup things since that time as I explained the above concept… ex… if you start an incremental backup of “since 6/3/2018” starting at 9:00 am today and finish it at 10:00 am today, if you wanted to ensure you back up every change since your last backup next time you would want to punch in since 9:00… Does that make sense?
thank you very much , it does help indeed
This topic was automatically closed 6 days after the last reply. New replies are no longer allowed.