On Wed, 15 Apr 2009 08:48:32 -0500, Mark Zelden wrote: >On Wed, 15 Apr 2009 10:50:37 +0200, R.S. <[email protected]> wrote: > >>By the way: is there any procedure to defrag HFS/ZFS ? >>I mean some process similar to PDS compress or KSDS reorg. >>Is there any need to do it? >>How to measure it? >> >>Further explanation: I'm not talking about defragmentation o f volume >>containing HFS dataset, rather about defragmentation of the dataset content. >> >>-- > > >For HFS, it shouldn't be needed - similar to PDSE (assuming the files within >the HFS aren't in use). Pages from deleted files or index pages are >can be reused after the last connection to the file has been terminated. >See similr past discussions on PDSE (especially in the LNKLST) in the >archives. > >For zFS, space is reused also. I suggest you read the zFS admin guide and >in particular the section on zFS disk space allocation that describes how >system and user areas are allocated in the aggregate. > >Do you have a reason or evidence that makes you think you need to >defrag / reorg an HFS or zFS?
I don't know, but ..... The space on a PC is reused too. In that environment, the reason is not to make the space available, but to improve performance. It seems likely that after a sufficiently large number of changes, files in the HFS (or members in the PDSE) could have their blocks scattered enough to perform poorly. That said, I make heavy use of PDSEs and have never given a thought to reorganizing them. -- Tom Marchant ---------------------------------------------------------------------- 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
