A vSphere administrator manages a three host cluster with 20 VMs. The HA cluster is configured
with the Host Failures the Cluster Tolerates admission control policy and all other settings are set
to default values. The administrator determines that one of the VMs is not able to power on. After
further inspection, it is determined that this VM cannot power on because of a very large CPU
reservation.
Which cluster advanced HA setting can the administrator modify to enable the virtual machine to
power on?
A.
Lower das.vmcpumaxmhz attribute value
B.
Higher das.vmcpuminmhz attribute value
C.
Lower das.slotcpuoutmhz attribute value
D.
Higher das.slotcpuinmhz attribute value
Explanation:
D is correct
If you have just one VM with a really high reservation you can set the following advanced settings to lower the slot size being used during these calculations: das.slotCpuInMHz or das.slotMemInMB. The advanced setting das.slotCpuInMHz and das.slotMemInMB will allow you to specify an upper boundary for your slot size
C is correct. Lower das.slotcpuoutmhz attribute value will decrease the slot size hence those powered on VMs would consume less reservation capacity, resulting in cluster available slots increase.
http://geekswing.com/geek/vmware-cpu-and-ram-reservations-fixing-insufficient-resources-to-satisfy-configured-failover-level-for-ha/
Slot size is calculated using CPU reservations of powered on VMs. The large CPU reservation VM distorts the slot size calculation, resulting in an artificially low slot count for the host (in other words, the host has enough resources available to support all the VMs, but the low slot count calculation won’t let the host power on the large CPU VM).
http://pubs.vmware.com/vsphere-50/index.jsp?topic=%2Fcom.vmware.vsphere.avail.doc_50%2FGUID-85D9737E-769C-40B6-AB73-F58DA1A451F0.html
If your cluster contains any virtual machines that have much larger reservations than the others, they will distort slot size calculation. To avoid this, you can specify an upper bound using using the das.slotcpuinmhz or das.slotmeminmb advanced attributes.
http://pubs.vmware.com/vsphere-50/index.jsp?topic=%2Fcom.vmware.vsphere.avail.doc_50%2FGUID-E0161CB5-BD3F-425F-A7E0-BF83B005FECA.html
Not real value as far as I can tell:
Lower das.slotcpuoutmhz attribute value
C is correct
das.slotcpuinmhz
Defines the maximum bound on the CPU slot size. If this option is used, the slot size is the ‘smaller’ of this value or the maximum CPU reservation of any powered-on virtual machine in the cluster.
Yes, C is the correct answer
If your cluster contains any virtual machines that have much larger reservations than the others, they will distort slot size calculation. To avoid this, you can specify an upper bound for the CPU or memory component of the slot size by using the das.slotcpuinmhz or das.slotmeminmb advanced attributes, respectively.
Unable to find *any* reference to “slotcpuOUTmhz” or “vmcpuMAXmhz” in any VMware documentation. Thus, A and C is incorrect.
das.slotcpuinmhz: “Defines the maximum bound on the CPU slot size. If this option is used, the slot size is the smaller of this value or the maximum CPU reservation of any powered-on virtual machine in the cluster.”
A good blog about it: http://www.yellow-bricks.com/2010/11/18/das-slotcpuinmhz-and-das-slotmeminmb/
das.vmcpuminmhz: “Defines the default CPU resource value assigned to a virtual machine if its CPU reservation is not specified or zero. This is used for the Host Failures Cluster Tolerates admission control policy. If no value is specified, the default is 32MHz.” (the default is 256Mhz in 4.1, but dropped to 32Mhz in 5.0)
D is the correct answer
das.slotcpuinmhz
Defines the maximum bound on the CPU slot size. If this option is used, the slot size is the smaller of this value or the maximum CPU reservation of any powered-on virtual machine in the cluster.
https://pubs.vmware.com/vsphere-50/index.jsp?topic=%2Fcom.vmware.vsphere.avail.doc_50%2FGUID-E0161CB5-BD3F-425F-A7E0-BF83B005FECA.html
Vamos supor que no cluster sobrou dois slots com 200 mhz cada. Afirmando que é necessário reservar 500mhz, o aumento do slot para 250mhz resolve ESSE problema, possivelmente criando outros.
http://pubs.vmware.com/vsphere-50/index.jsp#com.vmware.vsphere.avail.doc_50/GUID-85D9737E-769C-40B6-AB73-F58DA1A451F0.html?resultof=%2522%2573%256c%256f%2574%2563%2570%2575%2569%256e%256d%2568%257a%2522%2520
Cが正解ってことでいいんだろうか・・
A.
Lower das.vmcpumaxmhz attribute value – When upper boundary needs to be specified.
B:Higher das.vmcpuminmhz attribute value – When lower boundary needs to be specified.
C:Lower das.slotcpuoutmhz attribute value – das.slotcpuOUT* not exist
D:Higher das.slotcpuinmhz attribute value – the advanced setting das.slotCpuInMHz and das.slotMemInMB allow you to specify an upper boundary for your slot size. When one of your VMs has an 8GB reservation this setting can be used to define for instance an upper boundary of 1GB to avoid resource wastage and an overly conservative slot size.