Safely de-allocate cores?

IDS 11.5 FC8W2 on SPARC Solaris 10. We have a Solaris VM ("Container") running with 68 cores. 4 or 5 Informix instances run on here. We wish to de-allocate 4 cores from the VM for IBM Informix licensing reasons. We're pondering whether we can safely do this dynamically. It's possible - probable maybe - that when we do so the core snatched away from the VM will be servicing an Informix vp. In which case, might IDS crash? Obviously we'll do it at a quiet time, but these are 24x7 systems. Would the advice be to down all the instances first ....? Thanks Neil PS I raised a PMR 46043 019 866.

Err... If the core is servicing sendmail or sshd, would it crash? I suppose this has more to do with the OS than with the application... But I'm curious to see the answer you'll get. I suppose you're not "pushing it" like... usin affinity? :) Regards On Tue, Jan 24, 2012 at 4:16 PM, NEIL TRUBY <neil.truby@ardenta.com> wrote: > IDS 11.5 FC8W2 on SPARC Solaris 10. > > We have a Solaris VM ("Container") running with 68 cores. 4 or 5 Informix > instances run on here. > > We wish to de-allocate 4 cores from the VM for IBM Informix licensing > reasons. > We're pondering whether we can safely do this dynamically. It's possible - > probable maybe - that when we do so the core snatched away from the VM > will be > servicing an Informix vp. In which case, might IDS crash? > > Obviously we'll do it at a quiet time, but these are 24x7 systems. Would > the > advice be to down all the instances first ....? > > Thanks > Neil > > PS I raised a PMR 46043 019 866. > > > > ******************************************************************************* > Forum Note: Use "Reply" to post a response in the discussion forum. > > -- Fernando Nunes Portugal http://informix-technology.blogspot.com My email works... but I don't check it frequently... --485b397dd695de640c04b7488969

No affinity! I'm sure a running Informix vp *would* crash! It's whether that'll bring Informix down, or just crap out one application user. The latter is acceptable. Sod the bloody customers! ;-)

Whether the engine will crash depends on which VP is killed. If the main CPU VP (VP#1), the admin VP, or the miscellaneous VP crashes whichever of these three that remains will perform a safe shutdown. If one of the other VPs is killed the engine is supposed to continue running unless that VP was in a critical code segment and the defunct VP may even be restarted depending on which type it was. Art Art S. Kagel Advanced DataTools (www.advancedatatools.com) Blog: http://informix-myview.blogspot.com/ Disclaimer: Please keep in mind that my own opinions are my own opinions and do not reflect on my employer, Advanced DataTools, the IIUG, nor any other organization with which I am associated either explicitly, implicitly, or by inference. Neither do those opinions reflect those of other individuals affiliated with any entity with which I am affiliated nor those of the entities themselves. On Tue, Jan 24, 2012 at 11:49 AM, NEIL TRUBY <neil.truby@ardenta.com> wrote: > No affinity! > > I'm sure a running Informix vp *would* crash! It's whether that'll bring > Informix down, or just crap out one application user. The latter is > acceptable. Sod the bloody customers! ;-) > > > > ******************************************************************************* > Forum Note: Use "Reply" to post a response in the discussion forum. > > --bcaec5186cbe03182a04b74906a6

original post: DS 11.5 FC8W2 on SPARC Solaris 10. We have a Solaris VM ("Container") running with 68 cores. 4 or 5 Informix instances run on here. We wish to de-allocate 4 cores from the VM for IBM Informix licensing reasons. We're pondering whether we can safely do this dynamically. It's possible - probable maybe - that when we do so the core snatched away from the VM will be servicing an Informix vp. In which case, might IDS crash? Obviously we'll do it at a quiet time, but these are 24x7 systems. Would the advice be to down all the instances first ....? Thanks Neil PS I raised a PMR 46043 019 866. response: Well I think this is going to be highly dependent on what Solaris does when you remove a core. If I had to assume what it does, I'd assume it would mark that processor in the kernel as something where you can't schedule a thread/process to run on it, and then when it was not running anything (it's run queue was drained), remove it so that it's no longer visible to the kernel scheduler etc...However, if the OS does something like send a signal to the process running on the core you are trying to remove, and it's a signal we (Informix) don't handle and has some default behavior to core dump...then if a oninit process was running on the core when you did it, then yeah, the engine is going to crash because if any oninit process dies, the adm vp detects it and aborts the server. So without details on how Solaris goes about trying to remove the core, I don't think I can comfortably say how safe it is to do it with an Informix instance online. IBM Informix Advanced Support APD Team Jacques Renaut