A single virtual machine can have 24,576 devices. This is an arbitrary
limit to control the amount of internal control blocks that take up main
memory below 2G.
A VM LPAR will support the number of real devices allowed to be defined via
IOCP to a single LPAR in subchannel set 0. This is defined in Appendix F
of the IOCP User's Guide. It is model dependent. For example, a 2094
supports 65,280 devices.
Steve Wilkins
IBM VM Development
z/VM I/O Strategy
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|Alan Ackerman <[EMAIL PROTECTED]>
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|IBMVM@LISTSERV.UARK.EDU
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| Date: |
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|11/06/2008 03:55 AM
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|Re: Constraint of zVM on number of Devices Support
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On Fri, 31 Oct 2008 13:09:39 +0100, Kris Buelens <[EMAIL PROTECTED]>
wrote:
>I guess it is 64K (from 0000 to FFFF) The infoirmation probably is in
>the z/VM General Information manual.
>
>2008/10/31 Yee Fong Ooi <[EMAIL PROTECTED]>:
>>
>> Hi,
>> I am new in zVM world. Can anyone let me know or tell me where can I f
ind
>> the zVM information of the number of devices can zVM support. Will it
be any
>> problems if I share the same IOCDS for zOS with zVM, where the number
of
>> devices defined in the IOCDS more than 16384. (The number of addresses
for
>> DASDs alone is 16384).
>>
>> FYI, we have 6 LPARs on the z9 machine and plan to run zVM on one of t
he
>> LPARs. All the LPARs in z9 machine are sharing the same IOCDS.
>>
>> Thank you.
>>
>> Regards,
>> Yee Fong Ooi
>> 黄 宇 雄
>>
>
>
>
>--
>Kris Buelens,
>IBM Belgium, VM customer support
I don't know if this is relevant, but there is a limit of 24,567 devices
per virtual machine. I found
this limit in a Reed Mullen presentation. I think the limit is on the web
somewhere, but I cannot
find it. Dennis O'Brien may know.
Alan Ackerman
Alan (dot) Ackerman (at) Bank of America (dot) com
