I would concur with Rob's recommendation to measure. Some of our app team were shocked that they could get higher throughput by driving more workload to a single node at our F5 layer. This caused problems on the x86 deployment.
Sent from my iPhone > On Mar 13, 2015, at 6:22 AM, Rob van der Heij <[email protected]> > wrote: > > Also look at performance data and see whether it makes sense what you want > to do. I have seen installations that were spreading the load over a dozen > front-end servers all running on the same z/VM image, with a lot of the > requests just queue for the back-end database. You can burn a lot of > resources just to determine which server should handle the request, and may > achieve little when they share the resources. > > In an architecture from the discrete world, it is not always obvious which > risks are mitigated by what part of the solution. When you transpose that > to a Linux on z/VM implementation, some of the infrastructure failures do > not apply or may not be covered by the solution (eg "hardware fail" is not > fixed by using another Linux guest on the same z/VM LPAR). Using multiple > members on different machines in an SSI cluster covers differnet issues. > > Duplicating servers that hold no application data is fairly simple, but > things get hairy when you duplicate databases. Business may well justify a > HA setup, but remember this is not commodity hardware where servers fail > for trivial reasons. One of the reasons for using z Systems is that you > sometimes can avoid some of the complexity that comes with redundancy on > higher levels in the design. > > When possible, I want to drive the virtual machines at their most efficient > load. When a single server could do, it's not more efficient to spread it > over a dozen sharing the same resources. Do some measurements to find the > healthy load for your application, and monitor usage for those values and > add resources when needed. > > Rob van der Heij > http://www.velocitysoftware.com/ > >> On 13 March 2015 at 08:52, Berthold Gunreben <[email protected]> wrote: >> >> Hi, >> >> Starting with SLES12, there is haproxy included in the HA part of SLES. >> >> http://www.haproxy.org/ >> >> Berthold >> >> On Thu, 12 Mar 2015 19:10:07 +0000 >> "Stewart, Lee" <[email protected]> wrote: >> >>> Does anyone know of an IP “sprayer” for Linux on Z? (To send >>> arriving requests on to one of several servers, round robin or load >>> balanced.) >>> >>> Since this isn’t a WAS implementation, the DM with WAS isn’t a >>> choice…. >>> >>> Thanks, >>> Lee >>> >>> Lee Stewart ● VM System Support ● Visa ● Phone: 6(750)4601 - >>> +1-303-389-4601 ● [email protected] >>> >>> >>> ---------------------------------------------------------------------- >>> 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/ >> >> >> >> -- >> ---------------------------------------------------------------------- >> Berthold Gunreben Build Service Team >> http://www.suse.de/ Maxfeldstr. 5 >> SUSE LINUX GmbH D-90409 Nuernberg, Germany >> GF: Felix Imendörffer, Jane Smithard, Jennifer Guild, Dilip Upmanyu, >> Graham Norton HRB 21284 (AG Nürnberg) >> >> ---------------------------------------------------------------------- >> 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/ > > ---------------------------------------------------------------------- > 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/ ---------------------------------------------------------------------- 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/
