Re: OS390 Guests using GRS and Sharing DASD with virtual RESERVE/RELEASE under z/VM
Sdc Envoyé de mon iPhone Le 22 mai 2010 à 22:30, Kris Buelens kris.buel...@gmail.com a écrit : When you write CP continue to check until DASD is released. this sounds as if you think CP is executing code all the time a disk is reserved. That indeed would be high overhead. No, CP doesn't need to be active all the time, the only thing it must do is inspect some flag when IO's happen on disks with Virtual R/R. I wouldn't think the CP overhead for virtual R/R is noticable. And, when a disk is virtually reserved, the whole guest wouldn't need to wait, just that IO will wait, the guest can do other things. 2010/5/22 TaeMin Baek tmb...@kr.ibm.com We are using GRS ring mode in three OS/390 V2.10 in Baseplex enviroment under z/VM v6.1 on z10 to share DASD and dataset with serialization between OS/390 guests and z/VM provide shared full-pack minidisk with using virtual RESERVE/RELEASE. While system is running, Suervisor CPU usage is high up to 30%~40% of Total CPU Usage on Performance Toolkits. ex) Total CPU % : 67.4% Superv. CPU : 29.8% Emulat. CPU : 37.6% When one guest OS/390 access to a certain dataset, 1) z/VM CP control the DASD and set it reserved 2) if other OS/390 guest try to access different dataset in same DASD, it must wait and CP continue to check until DASD is released. Is the above logic of shaing DASD is right? If it is right, i think GRS is useless now and it can give more workload to CP. Today we tried to change sharing DASD method from with using Virtual Reseve/Release to without using Virtual Reseve/Release. What i mean is that i don't use MDISK with 'V' option. Only define MDISK with 'MW' option. I want to let GRS in OS/390 to control dataset level sharing like in Native LPAR mode. I guess it might reduce the CP workload relate to reserve/release DASD. But the problem is JES failed to start because it cannot access the volume containg checkpoint dataset. The message said the volume containing checkpoint dataset is not shared. Is there anybody who use GRS in Sysplex or Baseplex? Do you use GRS and Sharing DASD with Virtual Reseve/Release? How is your CPU utilization? Supervisor CPU% is high like us? Is there any tuning point to reduce the Supervisor CPU Usage? Regards Tae Min Baek Mmaa Bldg, 467-12 Dogok-Dong Advisory IT ArchitectSeoul, 135700 z/Linux Team Korea IBM Sales Distribution, STG Sales Phone: +822-3781-8224 Mobile: +82-010-4995-8224 e-mail: tmb...@kr.ibm.com -- Kris Buelens, IBM Belgium, VM customer support
Re: OS390 Guests using GRS and Sharing DASD with virtual RESERVE/RELEASEbgggtggncv under z/VMnjxjgj
Ccghhjjkkjjkkjvjhjjklknbvvbbbvvknbkbbbnbs:.. WkfbbSfffjjh Envoyé de mon iPhone Le 22 mai 2010 à 22:30, Kris Buelens kris.buel...@gmail.com a écrit : When you write CP continue to check until DASD is released. this sounds as if you think CP is executing code all the time a disk is reserved. That indeed would be high overhead. No, CP doesn't need to be active all the time, the only thing it must do is inspect some flag when IO's happen on disks with Virtual R/R. I wouldn't think the CP overhead for virtual R/R is noticable. And, when a disk is virtually reserved, the whole guest wouldn't need to wait, just that IO will wait, the guest can do other things. 2010/5/22 TaeMin Baek tmb...@kr.ibm.com We are using GRS ring mode in three OS/390 V2.10 in Baseplex enviroment under z/VM v6.1 on z10 to share DASD and dataset with serialization between OS/390 guests and z/VM provide shared full-pack minidisk with using virtual RESERVE/RELEASE. While system is running, Suervisor CPU usage is high up to 30%~40% of Total CPU Usage on Performance Toolkits. ex) Total CPU % : 67.4% Superv. CPU : 29.8% Emulat. CPU : 37.6% When one guest OS/390 access to a certain dataset, 1) z/VM CP control the DASD and set it reserved 2) if other OS/390 guest try to access different dataset in same DASD, it must wait and CP continue to check until DASD is released. Is the above logic of shaing DASD is right? If it is right, i think GRS is useless now and it can give more workload to CP. Today we tried to change sharing DASD method from with using Virtual Reseve/Release to without using Virtual Reseve/Release. What i mean is that i don't use MDISK with 'V' option. Only define MDISK with 'MW' option. I want to let GRS in OS/390 to control dataset level sharing like in Native LPAR mode. I guess it might reduce the CP workload relate to reserve/release DASD. But the problem is JES failed to start because it cannot access the volume containg checkpoint dataset. The message said the volume containing checkpoint dataset is not shared. Is there anybody who use GRS in Sysplex or Baseplex? Do you use GRS and Sharing DASD with Virtual Reseve/Release? How is your CPU utilization? Supervisor CPU% is high like us? Is there any tuning point to reduce the Supervisor CPU Usage? Regards Tae Min Baek Mmaa Bldg, 467-12 Dogok-Dong Advisory IT ArchitectSeoul, 135700 z/Linux Team Korea IBM Sales Distribution, STG Sales Phone: +822-3781-8224 Mobile: +82-010-4995-8224 e-mail: tmb...@kr.ibm.com -- Kris Buelens, IBM Belgium, VM customer support
Re: OS390 Guests using GRS and Sharing DASD with virtual RESERVE/RELEASEbgggtggncv under z/VMnjxjgj
On Sun, May 23, 2010 at 8:49 AM, Alain Benveniste a.benveni...@free.frwrote: Ccghhjjkkjjkkjvjhjjklknbvvbbbvvknbkbbbnbs:.. WkfbbSfffjjh Envoyé de mon iPhone I guess I don't want an iPhone then. You've become hard to understand. :-)
Re: OS390 Guests using GRS and Sharing DASD with virtual RESERVE/RELEASEbgggtggncv under z/VMnjxjgj
It's the special iPhone encryption app. It's perfectly readable from my iPhone. It says My hovercraft is full of eels. On May 23, 2010, at 8:48, Rob van der Heij rvdh...@gmail.commailto:rvdh...@gmail.com wrote: On Sun, May 23, 2010 at 8:49 AM, Alain Benveniste mailto:a.benveni...@free.fra.benveni...@free.frmailto:a.benveni...@free.fr wrote: Ccghhjjkkjjkkjvjhjjklknbvvbbbvvknbkbbbnbs:.. WkfbbSfffjjh Envoyé de mon iPhone I guess I don't want an iPhone then. You've become hard to understand. :-)
OT: Humour was Re: OS390 Guests using GRS and Sharing DASD with virtual RESERVE/RELEASEbgggtggncv under z/VMnjxjgj
And (for the older readers on the list) I thought it was AppleTalk Dave P.S. pity Google doesn't have an Apple Speak to English translator - Original Message - From: Neale Ferguson To: IBMVM@LISTSERV.UARK.EDU Sent: Sunday, May 23, 2010 2:36 PM Subject: Re: OS390 Guests using GRS and Sharing DASD with virtual RESERVE/RELEASEbgggtggncv under z/VMnjxjgj It's the special iPhone encryption app. It's perfectly readable from my iPhone. It says My hovercraft is full of eels. On May 23, 2010, at 8:48, Rob van der Heij rvdh...@gmail.com wrote: On Sun, May 23, 2010 at 8:49 AM, Alain Benveniste a.benveni...@free.fr wrote: Ccghhjjkkjjkkjvjhjjklknbvvbbbvvknbkbbbnbs:.. WkfbbSfffjjh Envoyé de mon iPhone I guess I don't want an iPhone then. You've become hard to understand. :-)
Re: OS390 Guests using GRS and Sharing DASD with virtual RESERVE/RELEASEbgggtggncv under z/VMnjxjgj
Klaatu Baratu Nicto? On May 23, 2010, at 2:49 AM, Alain Benveniste a.benveni...@free.frmailto:a.benveni...@free.fr wrote: Ccghhjjkkjjkkjvjhjjklknbvvbbbvvknbkbbbnbs:.. WkfbbSfffjjh Envoyé de mon iPhone Le 22 mai 2010 à 22:30, Kris Buelens mailto:kris.buel...@gmail.comkris.buel...@gmail.commailto:kris.buel...@gmail.com a écrit :
Re: OS390 Guests using GRS and Sharing DASD with virtual RESERVE/RELEASEbgggtggncv under z/VMnjxjgj
Hi Sorry for that ! My 5 years old girl tried to give an answer... Addiction to VM has no age ! Alain Benveniste Envoyé de mon iPhone Le 23 mai 2010 à 16:15, David Boyes dbo...@sinenomine.net a écrit : Klaatu Baratu Nicto? On May 23, 2010, at 2:49 AM, Alain Benveniste a.benveni...@free.fr wrote: Ccghhjjkkjjkkjvjhjjklknbvvbbbvvknbkbbbnbs:.. WkfbbSfffjjh Envoyé de mon iPhone Le 22 mai 2010 à 22:30, Kris Buelens kris.buel...@gmail.com a éc rit :
Re: OS390 Guests using GRS and Sharing DASD with virtual RESERVE/RELEASEbgggtggncv under z/VMnjxjgj
Clearly she was on to something. On 05/23/2010 09:32 AM, Alain Benveniste wrote: Hi Sorry for that ! My 5 years old girl tried to give an answer... Addiction to VM has no age ! Alain Benveniste Envoyé de mon iPhone -- Rich Smrcina Phone: 414-491-6001 http://www.linkedin.com/in/richsmrcina Catch the WAVV! http://www.wavv.org WAVV 2011
