Gil, Yesterday Giovanni Bozzetti had given me the same suggestion and I had the same thought so I did some experimenting. Here's what I found. I created a 3390-3 disk pack 90% utilized with IDMS database files - about 115 datasets on the pack. I ran the DFDSS DUMP job sending the output to DD DUMMY (after finding out the hard way that DFDSS COPY won't send to DUMMY) and the job ran in about 25 seconds, and consumed a total of 682 EXCPs, and .01 minutes TCB time. This is on a Multiprise 3000 box and an ancient RVA disk array.
I then put the data back on the pack using DFDSS COPY from a production pack - actually using SnapShot under the covers. Putting the data back took over 4000 EXCPs, .04 minutes TCB, and 1.5 minutes of wall clock. Running the same DUMP job without the DELETE PURGE yielded 204 EXCPs, and immeasurable TCB time, as well as running in 2 seconds. So apparently it does optimize. Rex In a recent note, Ron and Jenny Hawkins said: > Date: Wed, 1 Feb 2006 00:29:20 +0800 > > The old way to kill a bunch of files through a mask was to use DFDSS > to back up and delete the files, with the output assigned to DUMMY. > Yow! Wasn't that rather I/O intensive? (I ask even though I often aver "Silicon is cheaper than carbon.") Or did DFDSS recognize and optimize the output=DUMMY case? -- gil -- StorageTek INFORMATION made POWERFUL ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
