Thanks Bruce. I believe FDRPAS is going to be used for the migration. Craig
-----Original Message----- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Bruce Black Sent: Friday, January 13, 2006 2:54 PM To: [email protected] Subject: Re: Migration to Shark > > >We are migrating from Amdahl DASD to a Shark (Model 800). No one here >has experience with this. A DBA asked the following questions: > >What are the performance differences between volumes defined as MOD-3, >MOD-9, >MOD-27? > > I presume you are asking this about the Shark. On a gross level, no difference in performance, the number of cylinders is not relevant to performance. there is an issue, of course, if you put a lot more datasets on the larger disks, if it results in a lot more concurrent I/Os to those datasets. The Shark will certainly perform much better than the Amdahl, but putting datasets that used to be on 9 3390-3s to a single -27 and running all the same applications may result in a bottleneck. >What are the implications of changing a volume to a PAV volume? > > PAV is designed to address the bottleneck, by allowing multiple concurrent I/Os to a single volume. As long as the I/Os are all READs, or are WRITEs to different datasets (different extents on the volume), they will be allowed to execute concurrently and give you back the performance that you used to get on multiple smaller disks. PAV is a very good thing and has very little downside. >What type datasets/databases, if any, are required to be on their own >volumes? > Anything that is subject to RESERVEs of more that a few moments (such as JES checkpoint datasets) and some performance sensitive datasets (such as paging datasets, but PAV improves performance for multiple paging ds on a single volume). Now that I have paid my dues by answering your questions, let me put in a plug for our volume migration software, FDRPAS. FDRPAS can migrate your volumes non-disruptively, while it is in use. See our web site below or call and ask for sales. -- Bruce A. Black Senior Software Developer for FDR Innovation Data Processing 973-890-7300 personal: [EMAIL PROTECTED] sales info: [EMAIL PROTECTED] tech support: [EMAIL PROTECTED] web: www.innovationdp.fdr.com ---------------------------------------------------------------------- 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 ---------------------------------------------------------------------- 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
