Re: ontape and large delays reaching first 10% complete

On Mon, 18 Aug 2003 16:19:26 -0400, John Hardin wrote: All IDS versions after 7.24 perform a quick survey of the dbspaces, chunks, and extents before doing anything else. This information gathering step speeds the total archive time by permitting the engine to ignore empty pages. It's that front-end load you are seeing. Previous versions did not know what pages were empty until they read them so often you would see an archive go from 60% to 100% in seconds when the engine ran out of pages in use. Art S. Kagel > All: > > I'm helping someone troubleshoot backup problems, and they just reported > something we both think is very odd: the ontape process takes over two > hours to reach the first 10% completion point, but after that it's about > twenty minutes per 10% step. > > What would cause the first ten percent of the backup to take so much > longer than the rest? > > Thanks. > > (IDS 9.21.UC2 on Linux) >

On Mon, 18 Aug 2003 15:26:55 -0400, Art S. Kagel wrote: > On Mon, 18 Aug 2003 16:19:26 -0400, John Hardin wrote: > > All IDS versions after 7.24 perform a quick survey of the dbspaces, > chunks, and extents before doing anything else. This information > gathering step speeds the total archive time by permitting the engine to > ignore empty pages. It's that front-end load you are seeing. Previous > versions did not know what pages were empty until they read them so often > you would see an archive go from 60% to 100% in seconds when the engine > ran out of pages in use. Thanks, Art. I still see that behavior on 9.x systems. From last night: Informix Dynamic Server Version 9.30.UC2 -- On-Line -- Up 11 days 09:22:27 -- 169292 Kbytes Please mount tape 1 on /var/opt/informix/inst10/backups/level0.pipe and press Return to continue ... 10 percent done. 20 percent done. 30 percent done. 40 percent done. 50 percent done. 60 percent done. 70 percent done. 100 percent done. Is there any way to speed the scan up? Two hours seems a bit excessive... -- John Hardin KA7OHZ <johnh@aproposretail.com> Internal Systems Administrator voice: (425) 672-1304 Apropos Retail Management Systems, Inc. fax: (425) 672-0192 ----------------------------------------------------------------------- "...in retrospect, we probably should have turned it on by default." - Craig Mundie, Microsoft CTO, on shipping Windows XP with the much-hyped "Internet Connection Firewall" turned off by default