Hi George, On Sat, 20 Oct 2007 08:29:03 -0500, George Dranes <[EMAIL PROTECTED]> wrote: >We have a 3494 ATL with 3590 drives. When we initially set this up, the >Magstar Redbook I used said to leave the volume count for the data class as >1 since it is not used for tape. Yet I see IBM documentation apars for the JCL >manual ( OA10660) which add volume count to attributes that apply to tape >datasets. Which is it??? If true I guess I've never went over 1 tape for a >single dataset. Also if were a stacked tape and a dataset was split over 2 >volumes, would this pertain? What do others use for this value? Thanks for >any help!
I wasn't sure what year you set up 3494 or which Redbook (and whether that one happened to have a mistake), so looking at current doc.: z/OS 1.9 DFSMS Storage Admin Ref (that's the 18 MB with 1,580 pages, you're right, Tom), SC26-7402-08: "Defining Record and Space Attributes for Data Class ... Volume Count specifies the maximum number of SMS-managed DASD or mountable volumes a data set can span, with the following exceptions. Valid values are 1 through 59. ... For managed mountable volumes, this value can be overridden by the volume count specified in JCL up to a maximum of 255. Dynamic volume count has no affect to tape data sets. Volume count is ignored for data sets to which no storage class is assigned. The default is 1. Note: In JES3 systems, volume count is also ignored for managed mountable data sets. ... Dynamic Volume Count Dynamic Volume Count is used during allocation processing to determine the maximum number of volumes a data set can span. The number can be in the range 1 through 59. The default value is 1. 59 is the z/OS volume limit." Also, from IBM TotalStorage 3494 Tape Library: A Practical Guide to Tape Drives and Tape Automation, SG24-4632-07: "Defining Data Classes A Data Class provides the tape device selection information or tape datasets. The attributes that you can specify are: ... - The maximum volume count that your dataset can span ... Volume Count: Specify the maximum number of cartridges that you expect to use to store a dataset in this Data Class. Note: Coding a small value in the volume count parameter can cause job abends. This is especially true if you migrate from a native 3590 or 3592 environment to a VTS/TS7700 solution without changing your JCL. This occurs because the cartridge capacity is significantly different between a 3590 or a 3592 and a 3490E." So I think the answer is something like: If someone said *dynamic* volume count, that does not apply; If volume count, then it does apply to SMS- managed tape, except for JES3 and data sets to which no storage class is assigned. And bear in mind that it can be overridden by the volume count specified in JCL. HTH, Mike Baldwin Cartagena Software Ltd. http://www.cartagena.com +1 905-887-0755 1-888-USE-TAPE ---------------------------------------------------------------------- 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
