Dave, 1-3ms disconnect time is pretty good for sequential IO on Iceberg. Early Iceberg and RVAs I came across were typically 20-50ms disconnect time during batch - I had the first ICEBERG in ASIA.
Ron > -----Original Message----- > From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On > Behalf Of David Andrews > Sent: Wednesday, April 09, 2008 8:49 AM > To: IBM-MAIN@BAMA.UA.EDU > Subject: Re: [IBM-MAIN] Sequential Data Striping > > On Tue, 2008-04-08 at 07:17 -0700, Ron Hawkins wrote: > > The Iceberg's sequential pre-fetch performance was not one of its > finest > > moments. If you are seeing disconnect time of 10ms or more for your > > sequential IO then restricting your work to 8 stripes may not be the > best > > thing for your workload. > > 1-3ms seems typical, with the current snapshot showing a max of 4.2. > > > A larger number of stripes and corresponding BUFNO > > changes would increase the IO transfer and cache miss overlap. > > "Cache miss overlap" -- hadn't thought about that, good catch. > > I'm leery of striping things indiscriminately; there's a cost involved > with allocating additional extents for multivolume datasets. "F > CATALOG,REPORT,PERFORMANCE" on my system reports DADSM scratch time of > 139ms, which I (without any direct evidence) attribute to SVAA's > dynamic > space reclaim function. Maybe one of these days I'll turn that off and > see if interval space management improves DADSM scratch any. > > -- > David Andrews > A. Duda and Sons, Inc. > [EMAIL PROTECTED] > > ---------------------------------------------------------------------- > 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
