-1

Back up schedule for log backup (using Ola's scripts) as follows:

  • Start Time - 2AM
  • End Time - 11.59.59PM
  • Interval - Every 15 minutes.

On November 5th, all the back ups went as detailed above. Normally no log back up exists at 1AM, but on one of the servers after the 11:45PM back up there is a log back up at 1AM whereas other servers have log backups that start at 2AM.

My question is: why there is a back up at 1AM on one server, when all the other servers don't have a log backup at that time? Will this break the LSN?

When restoring do I need to restore 11:45PM then 1AM then 2AM and so on?

The LSN are given below

11 45pm Log- first LSN: 85246:1956:1, last LSN: 85246:3496:1

12.00 Full- first LSN: 85246:4241:180, last LSN: 85257:583:1

1 am log - first LSN: 85246:3496:1, last LSN: 86097:4867:1

2 am Log first LSN: 86097:4867:1, last LSN: 86105:2224:1,

2.15 am Log - first LSN: 86105:2224:1, last LSN: 86111:4864:

Any help will be greatly appreciated.

SqlNovice
  • 654
  • 3
  • 13
  • 21

1 Answers1

1

Based on the LSNs in the log files, you should be fine.

If restoring from your full backup taken at midnight, you shouldn't need the 11:45 log file (it should be fully covered by the full backup); You'd restore:

  • the full backup
  • the 1AM log file
  • the 2AM log file
  • the 2:15 log file
  • and so on.

As to why a log backup was taken at 1AM? I can only speculate.

If there was no 2AM log backup on that server, it's at least remotely possible that the 2AM log backup managed to start before the system clock shifted the time to 1AM, and to record its activity after that happened. If that happened, when it went to set the time for the next run, it probably would have scheduled it for 2AM again, since it would see the time was (say) 1:01:07. I wouldn't say its likely, but I can't personally rule out the possibility (perhaps someone else can). To speculate even more wildly, if this happened on only one server, it could possibly be having some issues with it's clock chip. Is this server unique in any way (for instance, the oldest server in the farm)? Again, this is wild speculation, and I have nothing further to offer than the slim possibility.

More likely: is there a chance that there was an old job set up to take a log backup at 1AM on the first Sunday in November, or something like that?

RDFozz
  • 11,731
  • 4
  • 25
  • 38