Posted on 2001-09-03
We have recently had a sybase (11.9.2 on Solaris 2.6) based application installed - as most of our in house knowledge is Oracle based we are on a steep learning curve!
We have scripted a back up of each of the databases in turn -this is executed by cron daily.
We are unable to backup the transaction logs because the truncate log on checkpoint is set on - this hardly matters as I understand a checkpoint is performed before a backup so all data from the transactions logs would be flushed to the databases before my 2:00am backup.
However what we want is point in time recovery - if the database performs a checkpoint between the 2:00 am backups (which I assume it will) the transaction logs will truncate thus rendering any data written to the databases unrecoverable in the event of disk failure to the datbase disks and unrecoverable from the transaction logs because they have been truncated.
It strikes me that it would be better not to truncate the logs on checkpoint. However, this is not how the databases have been setup.
1) Can we change this option to stop the transacion logs truncating - i.e. is it likely to have an impact on the application (I appreciate that this is a question for the application designers - but I am really after general principles)?
2) I am used to Oracle where you can have archive logs being written to multiple destinations for security is there any equivalent mechanism Sybase - or is mirroring the transaction logs the only option?
Finally the Sybase documentation makes great play of the importance of running dbcc before backups and for various other integrity checking tasks - dbcc is not installed on either the development box or on the production box - does dbcc come as part of the Adaptive Server release?
Many thanks in advance