about consistency without the use of aaip

[Luca82]

Hi everyone, one customer aked me the following tricky question:

if I backup (or replicate) a vm that is running a database, let's suppose sql, in not consistent manner (without installing aaip), when I need to restore it, inside the machine I can find the sql transaction log files that allow me to make consistent the database even if the backup I made with veeam was not consistent. It's correct? Or without AAIP there is always the risk of having a corrupt / inconsistent backup? this question was asked with a view to using CDP in "short-term" mode: in case I need to restore an inconsistent (short-term) restore point, I can always make the database consistent thanks to the presence of the transaction logs, or they could also would they be inconsistent / corrupt?

[PetrM]

Hello,

It's an interesting question. Basically, short-term restore points of CDP are always crash-consistent and such points do not capture any pending I/O operations, thus it's not the best choice for database applications. However, transaction logs exist to guarantee the possibility to bring your database back to a consistent state after crash or hardware failure. Therefore, in both cases mentioned above you can make SQL database consistent if you have transaction log backups. I hardly imagine any kind of corruption after log backup has been created successfully. Only if log backup was running during restore point creation, such a log backup cannot be used for recovery purposes as it's simply inconsistent.

Anyway, it's strongly recommended to enable AAIP whenever it's possible: image-level backup, snapshot replica and long-term CDP.

Thanks!