Hmmm, that doesn't make any sense to me. I just checked my backup table and see similar results. If TSM has only taken 1 base file backup, then shouldn't there be only 1 extra version? My management class for this server is keeping 30 days worth of backups (unlimited versions). But I've got a heck of a lot of files older than 30 days. Plus I'm pretty sure I've only done 1 base file backup. Back to support ...!
The only reason I'm looking at sub-file backup is for space savings! Support did not mention when TSM takes a new base file - only that it doesn't use the 20 limit (this really didn't make any sense anyways - why send a new base file if you don't need to?). I assume TSM still follows the other methods documented in the Red Book or other papers: - if delta file exceeds 60% of base - if digital signature of reference file in cache does not match signature on server - if digital signature or reference file do not exist in the client cache Of course since these are not officially documented anywhere they could have changed by now (or in the future)! I'll keep you posted on anything I found out on this. Thanks, Tim -----Original Message----- From: Prather, Wanda [mailto:[EMAIL PROTECTED]] Sent: August 20, 2002 1:16 PM To: [EMAIL PROTECTED] Subject: Re: Sub-File Backup - Number of Delta File Backups Tim, I'm seeing the same results as you. If I run the backup table for a client and look for backups of specific files, I sometimes see more than 20 "versions" of the same file, even though I should only have 6. I concluded that it must be caused by the subfile backup - even if you tell TSM to keep only 6 versions, it can't expire the base version, no matter what, until a new base is taken. And I'm not sure you can guarantee a space savings on the server because of this. I'm using it to reduce the amount of data transmitted per DAY, which was a big issue with me due to having 450 clients on 1 TSM server. That was pretty easy to document using the accounting records, as we get pretty consistent numbers from day to day. Implementing subfile backup dropped my total daily load by 25-30% (and I'm pretty sure the biggest chunk was those .pst files). Did they mention to you when how TSM DOES decide to take a new base file now? Wanda -----Original Message----- From: Rushforth, Tim [mailto:[EMAIL PROTECTED]] Sent: Tuesday, August 20, 2002 11:55 AM To: [EMAIL PROTECTED] Subject: Re: Sub-File Backup - Number of Delta File Backups I've just received the following from TSM Support: Hello, After going through the code and confirming with development, the reference made in the Redbook is invalid. The original prototype for subfile backup had the limitation of 20 subfile backups before a new full ("base") backup was taken, but when subfile backup was implemented for general release, the 20-subfile backup limit was removed. The behavior the customer is seeing is correct. The information in the redbook must have been based on the prototype description, which is now obsolete. This is a case that demonstrates why Support does not officially support information documented in Redbooks, as the information contained in them can be incorrect or out of date. TSM does not have a limit for the number of subfiles that can be sent prior to a new base file being backed-up. . Regards, - - - - ADSM/TSM Support Team
