> I was wondering if it is possible for the backups of the onsite tape pool > to a copy pool to have the ability to cause the recovery log to fill if it > is copying a 200+ GB file? The file is a collection of event logs from WIN > servers. Every day it is writing one very large file (I've noticed it gets > to almost 300GB), and then when I am doing a tape to tape copy my log fills > at a tremendous rate. My log is in normal mode. I have TSM server 4.1.3 > on os/390. Lately I have also been running expiration at the same time and > of course I am doing other backups of tape pools and other administrative > jobs. Could my log just be filling up because it is running expiration, > reclamation, etc. at the same time? Thanks in advance for any advice you > might have!!!!
You are running into a phenomenon called log pinning. The nominally occupied region of the recovery log is bounded by head and tail pointers. The head pointer moves forward as new transactions are started. The tail pointer moves forward when the oldest existing transaction ends. Both pointers wrap around to the beginning of the log when they reach the end of the log. When the copying of the huge file is going on there will be one or more log entries relating to that operation just ahead of the tail pointer. There will be a huge area filled with log entries for transactions that have started and ended since the copying of the huge file started. There will be a small area just behind the head pointer containing log entries for the remaining pending transactions and possibly some entries for recently ended transactions. That huge area in the middle is considered to be occupied log space. When the copying of the huge file ends the tail pointer will advance to the end of the area containing recent transactions and the utilization will drop suddenly. The other activities running concurrently with the copying of the huge file are generating the transactions that keep moving the head pointer forward. Expiration is probably the biggest generator of transactions.
