Hi folks, What are the best practices for HyperPAV and LVM striping? I assumed that if you have HyperPAV enabled, you don't need to stripe the data. Is this true, or if not, what is the best practice for optimum performance?
I have lots of mod-9 ECKD with HyperPAV enabled, so I want to use LVM. So my two choices are standard LVM, or LVM striping. If I stripe across the disks I spread the I/O across the physical volumes, but my gut tells me I shouldn't have to do this, since HyperPAV is moving around aliases dynamically. For example, say I have 2 PVs and 4 HyperPAV aliases. If I send some heavy I/O through the Linux (device-mapper) block device, then I would assume: - #1, for the case with LVM striping enabled, LVM will spread the I/O to both PVs, and HyperPAV will assign 2 aliases to each PV since I'm banging on them both. - #2, for the case without LVM striping, HyperPAV will assign 4 aliases to the first PV since that's the only one in use. In either case, it seems I'm using all 4 aliases, so seems like I would get the same performance. Please correct me if I'm wrong. And if so, which of these configs is better? Lastly, is there a presentation or doc that talks about how to enable HyperPAV in Linux, or is bringing the HyperPAV aliases online enough to trigger the dasd driver to do the right thing? Thanks as always, -Brad -- Brad Hinson Solution Architect, Red Hat +1 (919) 360-0443 ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [email protected] 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/
