Dear
Add'l Volume Amount, This attribute is used during VSAM EOV processing, and is only applicable to any VSAM multivolume data sets allocated in the extended format. Is it only used for any VSAM multivolume data sets? Thanks a lot! Best Regards, Jason Cai 发件人： Gonzalo Cengotita 发送时间： 2011-05-03 19:25:48 收件人： IBM-MAIN 抄送： 主题： Re: Add'l Volume Amount On Tue, May 3, 2011 at 12:57 PM, ibmnew <[email protected]> wrote: > Dear > > > >It means that if the dataset is multivolume, when it expands to another > >volume you can decide wether you want to use the amount of the primary > >allocation or the amount of the secondary allocation to expand. > >Suppose you have a dataset created with SPACE=10,5 cylinders > > What situation do dataset expands to another volume ? > If the dataset is full, it will extent 5 cylinders. > > When it extent 5 cylinders,the volume is full. In this situation,does > dataset expand to another volume? > Yes, if the dataset is multivolume > Then it will : > > >If you filled with "primary" value the dataset wil try allocations in new > >volumes with 10 cylinders > >If you filled with "Secondary" value the dataset will try allocations in > new > >volumes with 5 cylinders > > > does it mean that if volume isn't full,dataset always extent 5 cylinders > and if volume is full,dataset always extent 10 cylinders? > > Yes, if you fill this field with "Primary" > > What is benefit of Add'l Volume Amount ? > You could have a large pool of many disks with a lot of fragmentation and in this situation, you will prefer "secondary" amount wich is usually less than primary. Keep in mind that the quantity of the allocation must be found all in one piece, no fragmentation is allowed, so you will get less errors if the allocation in a new volume try with the lesser value. (The example would be better if the dataset would have SPACE=2000,50 cylinders) Of course all of it depends on the size of the dataset, and the number of disks, etc I hope it is clear enough, English is not my mother tongue, too! Regards Gonzalo Cengotita > ---------------------------------------------------------------------- > 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 > -- Gonzalo Cengotita Quirce ---------------------------------------------------------------------- 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
