Tom, > On Tue, 6 May 2008 08:25:42 -0400, John Kington wrote: > > >Natasa wrote: > > > > > >> Hello, > >> in order to prevent releasing of unused space for some datasets, I > >> allocated it > >> yesterday with MC that has Partial release parameter set to 'No'. > >However, > >> today when I look at some of those datasets, they look like the space was > > > >> first released (primary extent is 1 cyl, allocated was 200), and then as > >the > >> data was loaded it took 11 secondary extents. This is exactly what I > >wanted > >> to prevent. Can someone explain to me how this happened? > >> > >> General Data Current Allocation > >> Management class . . : MCNORLSE Allocated cylinders : 221 > >> Storage class . . . : MEDIUM Allocated extents . : 12 > >> Volume serial . . . : SSP122 > >> Device type . . . . : 3390 > >> Data class . . . . . : DCDYNV Current Utilization > >> Organization . . . : PS Used cylinders . . : 204 > >> Record format . . . : FB Used extents . . . : 12 > >> Record length . . . : 3000 > >> Block size . . . . : 27000 > >> 1st extent cylinders: 1 > >> Secondary cylinders : 20 > >> Data set name type : SMS Compressible : NO > >> > > > >The fact that the allocated cylinders is greater than the used cylinders > >(221 > 204) leads me to believe that space was not released from the > >dataset (allocated cylinders would equal used cylinders). The 1st extent is > >just the size of the first extent and not the primary space allocation > >amount. Each allocation can be up to five extents, even more if you are > >using the storage space constraint relief features of SMS. I recommend you > >look at the fragmentation index on your volume(s) and run some defrags. > > I think it's unlikely that the volume is so fragmented that the first extent > allocated was only 1 cylinder, but that he was able to obtain a total of 220 > cylinders in 12 extents. It is especially unlikely considering that > the secondary > allocation is 20 cylinders. My understanding is that allocation is using first fit strategy and the first extent could be only one cylinder if the next four extents equal or exceed 249 cylinders. The primary allocation amount for nonvsam datasets is not retained after the creating job completes. > > It is more likely that something caused the primary allocation to be > 1 cylinder > with 11 secondary allocations of 20 cylinders each. Storage space constraint relief could cause this which is why I suggested looking at fragmentation. I probably should have included amount of free space on the volume or in the SMS pool. > > There is not enough information to guess how this might have happened. > I agree. If the OP has access to Dataset Audit Facility (DAF) from cbttape.org, the tale could be told. Regards, John
---------------------------------------------------------------------- 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
