I applaud you for your decision to place the user DB data on FCP SCSI. Out performs ECKD and allows you to have ALL LUN after formatting and inherent multi pathing NOT the 70% or so. the best part is that you now have made zlinux less "mainframe" and more main stream. Other platforms can now access without having to go thru hoops. For far too long typical mainframe bigots (i have been working on MF since IBM and my PSR days ala 1974) have brandished and espoused MF technology in the distributed world. In this world to beat them you have to join them and play nicely in the sea of data. My experience in the z/VM owned DASD world is its really not a necessity so long as you maintain PAV in the real disk mode. Not a big fan of PAV on mini disk for performance. PLus what is left which would reside on MDISK that needs that so called performance boost?
Richard (Gaz) Gasiorowski Lead Architect UTC Global CSC 3170 Fairview Park Dr., Falls Church, VA 22042 845-889-8533|Work|845-392-7889 Cell|rgasi...@csc.com|www.csc.com This is a PRIVATE message. If you are not the intended recipient, please delete without copying and kindly advise us by e-mail of the mistake in delivery. NOTE: Regardless of content, this e-mail shall not operate to bind CSC to any order or other contract unless pursuant to explicit written agreement or government initiative expressly permitting the use of e-mail for such purpose. From: Rob van der Heij <rvdh...@velocitysoftware.com> To: LINUX-390@vm.marist.edu Date: 03/20/2012 04:23 AM Subject: Re: FCP vs EDEV for system - best practice? Sent by: Linux on 390 Port <LINUX-390@vm.marist.edu> On Tue, Mar 20, 2012 at 7:04 AM, Grzegorz Powiedziuk <gpowiedz...@gmail.com> wrote: > Data disks for oracle I will build using direct attached FCP/SCSI. It is > pretty easy to manage, multipathing is working fine - no doubts over here. > But what about linux system disks? > I know that in general ECKD win over FCP. But does FCP win over EDEV when > we are talking about linux system? I am not sure "ECKD win over FCP" unless you talk about having performance instrumentation in the control unit and channel... Since you already have some data on FCP attached SCSI, you seem to have mastered some of the issues related to that (NPIV, performance instrumentation, etc). Some parts of that would be avoided when you have ECKD or EDEV. For some installations there is a big advantage in having access control in CP and RACF and space management in DIRMAINT. As long as you're talking about moderate I/O rate, the extra CPU cost of EDEV may be worth it. If you want to run your Linux systems management processes from CMS, then being able to handle the disks there is very attractive. As for multi-pathing etc, I'm not sure that is a definite must-have for everyone. I have seen several configurations where multi-pathing and PAV made things slower. The issues to make this work well for real life workload are not trivial. I'm currently looking at an ECKD device that I can read at 250 MB/s (single device, no PAV). With a lot of workloads this means disk I/O is not the limiting factor and you can invest your time on other things. -- Rob van der Heij Velocity Software http://www.velocitysoftware.com/ ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For more information on Linux on System z, visit http://wiki.linuxvm.org/ ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For more information on Linux on System z, visit http://wiki.linuxvm.org/
