David, You should probably be asking this question on the IMS listserv, but in order to remove, change, or add compression to a data base you will need to unload and then reload the data base using the old and new DBDs.
When you load the data base, unless you change the free space parameters, they will be the same as before. If you are going to have non-compressed data on the new data base, you may wish to re-assess your free space requirements, since you will not be having as many split segments as before. You have several options if you exceed the 8Gb limit: - Use can use a partitioning product, such as PDF or HALDB - You can use secondary data set groups IBM's compression product works fine. We have many customers that have been using it successfully for a long time. Tom Harper IMS Utilities Development Team Neon Enterprise Software, Inc. Sugar Land, TX -----Original Message----- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of David W. Cullum Sent: Thursday, November 13, 2008 2:12 PM To: IBM-MAIN@BAMA.UA.EDU Subject: How many shops use 3rd party compression for IMS DBs? We are currently evaluating IBM's compression product but will only be using it on 12 large DBs, is it even worth the DASD savings? We have about 300 VSAM/OSAM HIDAM databases and are running IMS 9. We also have mucho storage available but are concerned that some of our large DBs may go over the 8 gig limit once they are uncompressed or will they just allocate the existing free space in the DB? We are using DBT's compression routine at this time. David ---------------------------------------------------------------------- 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
