I have the following backup strategy set up:
My understanding so far, was: Differential backups do not truncate the transaction log, so, there's no relation between Diff and Log Backups and both could co-exist in parallel without affecting each other.
Based on this understanding, I thought that I would have two alternatives to perform a complete restore to the most recent state.
This alternative #1 works as expected with no issues.
This alternative #2 shows the following error.
Msg 4305, Level 16, State 1, Line 53 The log in this backup set begins at LSN 144000000122400001, which is too recent to apply to the database. An earlier log backup that includes LSN 73000000188800001 can be restored.
After analyzing the backup history, I can conclude that if there are Differential backups prior to Log Backups, the latest Differential backup MUST be restored before restoring backups.
So far, I have always thought that since Full/Diff backups do not affect the chain log, Differential backups were mostly meant to shorten recovery time by reducing the number of log backups to be restored.
However, as shown here, perform a complete restoration based only in log backups is not being allowed if DIFF backup hast not been restored, so, my question is:
What is the reason behind DIFF backup being required to allow LOG restores in Restore Sequence #2?