Berry, <The guest runs with attached DASD so MDC is not applicable in this case.>
Do you mean: attached to the VSE-guest or to the VM/ESA-guest? If attached to the VSE-guest: is there still a real performance benefit in attaching dasd to a 3rd level VSE-guest? Anyway, MDC has the potential of giving your VSE-throughput a real boost (it did in our case), so in order for the VSE-guest to benefit from MDC in the VM/ESA system, I would: - in the first level z/VM: attach the dasd to the 2nd level VM/ESA guest. - in the 2nd level VM/ESA: attach the dasd to SYSTEM, and define fullpack MDISKs for the 3rd level VSE guest. Also, if enough storage is available in VSE, add more buffers to your CICS LSR-pools and/or database system. Bye, Geert. -----Original Message----- From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of Berry van Sleeuwen Sent: woensdag 29 april 2009 12:01 To: IBMVM@LISTSERV.UARK.EDU Subject: Re: Third level VSE Hello Kris, The guest runs with attached DASD so MDC is not applicable in this case. It doesn't look like IO is the problem here. But obviously any command processed in the guest will cause double the load in the host VM. So I do= agree to avoid as much as possible. I don't know if MDC in the guest is possible or acceptable. Paging is not an issue. The host has 1G, the guest has 512M. The VSE runs= NOPDS and the guest VM doesn't page. Yes, we run PTK. Running in the current config the guest VM can run up to= 100%, and it does. When we assign 2 virtual CPU's to both VM and VSE (and= start TD) we have seen the guest running up to about 190%. Also VSE does show processing at 100% CPU. But even an increase to 2 CPU's doesn't lowe= r the transaction times for the transactions in question to an acceptable l= evel. Regards, Berry. DISCLAIMER This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify postmas...@vanbreda.be This footnote also confirms that this email has been checked for the presence of viruses. Informatica J.Van Breda & Co NV BTW BE 0427 908 174
