Mike, That's because you have to pay for or configure multi-path support for SCSI attached drives. Been that way since before Fibre Channel.
I wouldn't blame the IBM hardware for that - it supports multi-path access just fine. Ron > -----Original Message----- > From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of > Mike Schwab > Sent: Wednesday, October 13, 2010 1:28 PM > To: [email protected] > Subject: Re: [IBM-MAIN] When will MVS be able to use cheap dasd > > We have a ESS F20 box bought about 1999. We have had some repeated > NVS failures on it, when the mainframe was configured to block the > failing cluster, it continued to work. We moved off of it and > configured it for open systems. AIX boxes with 1 FC card. When it > went down, the AIX box was down too. Not configured to access the > same disk via multiple pathways. > > On Wed, Oct 13, 2010 at 1:12 PM, R.S. <[email protected]> wrote: > > W dniu 2010-10-13 03:05, Ron Hawkins pisze: > > [...] > > > >> The difference between the cost of midrange and enterprise storage has > >> little to do with end-to-end data protection, because it's all SCSI, SAS > >> and > >> SATA once your write leaves the FICON channel on Enterprise. It has much > >> more to do with survivability, availability, scalability, and software > >> options or lack thereof on midrange storage > >> > >> The best illustration of this were the last set of ratings that the now > >> defunct RAID Advisory Board issued, where most Enterprise Class > >> controllers > >> were classified as Disaster Tolerant Disk Subsystems, and midrange was > >> typically classified as Fault Tolerant Disk Subsystems. > >> > >> Typically midrange storage will stay connected and keep running if a > >> component fails, but FRU replacements, upgrades and suchlike are likely to > >> be disruptive - they're not five nines in all situations and that's why > >> they > >> are cheaper. > > > > The original question was: Why *THE SAME* dasd box costs less when it's sold > > for FBA (distributed) systems, and costs more when it's CKD. Same hardware, > > usually comparable set of software features. > > -- > > Radoslaw Skorupka > > Lodz, Poland > > > > > > -- > > BRE Bank SA > > ul. Senatorska 18 > > 00-950 Warszawa > > www.brebank.pl > > > > S d Rejonowy dla m. st. Warszawy XII Wydzia Gospodarczy Krajowego Rejestru > > S dowego, nr rejestru przedsi biorców KRS 0000025237 > > NIP: 526-021-50-88 > > Wed ug stanu na dzie 16.07.2010 r. kapita zak adowy BRE Banku SA (w ca o > > ci wp acony) wynosi 168.248.328 z otych. > > > > ---------------------------------------------------------------------- > > 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 > > > > > > -- > 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 [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
