24 byte blocks get 82 blocks per track. (96 blocks * 31 days) / 82 blocks = 37 tracks per month. Inefficient but a very small utilization. Copy to historical dataset to reblock.
On Tue, Jun 21, 2022 at 9:36 AM Paul Gilmartin <0000042bfe9c879d-dmarc-requ...@listserv.ua.edu> wrote: > > On Mon, 20 Jun 2022 21:55:07 -0700, Charles Mills wrote: > > >> But is loss of a single record disastrous? > > > >No, I said earlier, this is not banking transactions where a lack of 2-phase > >commit risks losing a bunch of money between the cracks. > > > What's your crash recovery plan? > o Create a new file and process both at report time? > o Continue writing to the same file with O_APPEND? > > Long ago, I reported an apparent I/O performance problem. Support examined > my code and explained that I used O_APPEND, which incurs significant > serialization overhead. I assume this is to preserve integrity if multiple > jobs > write to the same log file. > > (I mentioned this on MVS-OE and WJS quickly jumped in, saying he didn't > recognize the behavior, but a sysplex might add overhead. He'll be missed > when he retires at the end of the month.) > > The cost of O_APPEND is likely to be insignificant for your expected traffic. > And you don't expect multiple writers. I'd expect it to be worse for Classic > data sets: > ALLOCATE DISP=MOD > OPEN > PUT one record > CLOSE > FREE > (Adverse blocking!) > > -- > gil > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN -- Mike A Schwab, Springfield IL USA Where do Forest Rangers go to get away from it all? ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
