Jason Bradfield wrote:
Thanks Jeff.

FYI, These zones will be allocated to different clients each with root access to their zone and running their own software.

Ah. Yes, that would indicate tighter controls. You could even charge more for a higher cap... ;-)

Jeff Victor wrote:
Jason Bradfield wrote:

Ok.. to solve my immediate problem 16GB Physical and 16GB disk = total of 32GB Virtual If I were to create 3 zones and wanted to evenly allocate memory to all 3 and the global zone, would this config be ok

zonecfg:host30> add capped-memory
zonecfg:host30:capped-memory> set physical=4G
zonecfg:host30:capped-memory> set swap=8G
zonecfg:host30:capped-memory> end

Memory capping isn't really intended to solve the 'problem' of allocating memory, because usually there isn't a problem. Memory capping is intended to prevent memory hogs (accidental or otherwise) from impacting proper operation of other workloads. This allows you to choose large caps, improving resource usage efficiency.

With some v12n solutions, allocating memory is required. This has the potential of wasting memory - if one virtual server is not using all of its memory, another cannot.

With zones, memory allocation (and its wastefulness) is not necessary. Further, choosing a physical memory cap that is too low will result in unnecessary paging activity, which will significantly reduce performance on that one zone, and also affect performance of other zones, to some extent.

However, if you want to ensure that one zone does not use too much and impact other zones, measure (or estimate) its normal memory usage, and choose a value larger than that. After the zone is running, "prstat -Z" can be used to measure memory usage, both physical and swap.

With all of that in mind, in your situation I would choose much larger numbers than the ones shown above. But without understanding the normal resource consumption of your workloads, I can't guess at good values.

Finally, it usually helps to know that those caps can be changed while the zone is running, using rcapadm from the global zone.

Jeff VICTOR              Sun Microsystems            jeff.victor @ sun.com
OS Ambassador            Sr. Technical Specialist
Solaris 10 Zones FAQ:    http://www.opensolaris.org/os/community/zones/faq
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