Problem with backup

Hello, every time we release a copy with onbar , the Database server gets blocked one to three minutes. Is this normal ? Our version is 12.10.FC3WE and the command is onbar -b -w Thanks

Original post: Hello, every time we release a copy with onbar , the Database server gets blocked one to three minutes. Is this normal ? Our version is 12.10.FC3WE and the command is onbar -b -w Thank Response: The answer is possibly. At the start of every backup, the server has to perform a blocking checkpoint. This is different than what should be most checkpoints happening on a system. Most checkpoints would be what's called interval or non-blocking, meaning that the system is still able to perform write activity while the buffer pool flushing is happening, so there is normally only a very small block time. Durning a blocking checkpoint, the server blocks write activity for the duration of the entire checkpoint, which would include the buffer pool flushing. So if you h ave large buffer pools with high values for LRU min/max (which control page flushing between checkpoints) then yes, it may be normal for the server to have to block that long to complete all the IO required for the checkpoint. You should be able to look at the output of onstat -g ckp to see if the checkpoint that's happening at the start of the backups being kicked off is taking a long time because of "flush" time (that's the name of the column in the -g ckp output, and it is the time it took the server to flush all the dirty buffers in the buffer pool/s to disk. Anyway, I'd start looking there to get a better idea if this is normal or not. Jacques Renaut HCL Informix Advanced Support