On 30.10.2012 22:01, Roger Evans wrote:
My plan was to buy a 1-u intel server with lots of memory and put both there. But our Z enthusiast says we can put Redis and memcache on Z-Linux (under VM) without any loss of functionality or performance
The whole point of tools like memcache is to trade IO and CPU-intensive operations for lots of cheap memory. Memory on the Z isn't particularly cheap, and IO is highly performant, so I'd be careful about going down that route, myself.
(because we have extra capacity and "paging on Z doesn't cost anything").
Paging on the Z may not create the same overhead as paging on bitty boxes, but "doesn't cost anything" is, at best, an exaggeration. In my experience paging a guest with a JVM heap or an Oracle SGA, for example, just ends in tears. I'd test and confirm with my app stack if it were me.
Has anybody out there tried to use zLinux for these kinds of in-memory database and caching applications?
I haven't, but I know from painful experience that if the SGA of an Oracle guest starts paging, Oracle performance plummets. I would be surprised if Redis or memcache fared better. -- Rodger Donaldson [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/
