On Mon, Feb 23, 2009 at 03:41:03PM -0500, David K. Kelly wrote: > Thank you David and Ron for the quick responses. > > Let me explain what I'm trying to do. > > In zLinux I have a DB2 file system that is setup on one large 3390-27 > disk pack. And when I use Linux tools like iostat I see one disk > with one path to the Shark. What I would like to do is use the > eight paths to this single disk (yes, I would like multiple exposures > to the disks). How do I do that? Or maybe I already have this > configured or CP is doing it but I can not tell this with my limited Linux > commands? We do have Velocity and I can see lots of IO going > through. > > Also we don't used PAV and from what I understand that is more > of a zOS thing and we are a zVM shop. >
Let me explain it from the Linux point of view. For each disk linux sees it can submit one request at a time. Linux has no knowledge how this disk is connected to the storage system. So to submit more than one request at a time to the same disk there is only the possibility with PAV. If you can replace the one disk with set of smaller disks (rule: the more the better), this will boost the I/O. IBM published on http://www.ibm.com/developerworks/linux/linux390/perf/tuning_rec_dasd.html on how to set up storage configuration for good performance. The performance of a PAV with N paths and a striped volume with N disks is comparable. Ihno > Thank you > > David K. > > > > > > David Boyes > <dbo...@sinenomin > e.net> To > Sent by: Linux on LINUX-390@VM.MARIST.EDU > 390 Port cc > <linux-...@vm.mar > IST.EDU> Subject > Re: Help with zLinux DASD using > multiple paths > 02/23/2009 11:19 > AM > > > Please respond to > Linux on 390 Port > <linux-...@vm.mar > IST.EDU> > > > > > > > On 2/23/09 11:12 AM, "David K. Kelly" <dkke...@courts.state.va.us> wrote: > > > How can I configure multiple paths to a single disk in SUSE zLinux? I > have > > 8 paths to our Shark and I¹m running zLinux SUSE 10 in zVM V5.3 on > > a z9 and I want to configure multiple paths to a single > > 22.8 GB 3390-27 disk. > > Just to be sure, do you want the Linux guest to see multiple exposures to > the disk? If so, you need the PAV microcode to do that. > > If you just want it to exploit the physical paths, give the disk to CP as a > user volume, allocate the disk as a minidisk in the Linux directory entry, > and let CP worry about it. If the paths are in your IOCP, CP will > automagically use them. > > ---------------------------------------------------------------------- > 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 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 -- Best regards/Mit freundlichen Grüßen Ihno Krumreich "Never trust a computer you can lift." -- Ihno Krumreich i...@suse.de Projectmanager S/390 & zSeries Maxfeldstr. 5 +49-911-74053-439 D-90409 Nürnberg http://www.suse.de SUSE LINUX Products GmbH, GF: Markus Rex, HRB 16746 (AG Nürnberg) ---------------------------------------------------------------------- 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
