[Users] Can host hooks be used to implement the following policy to avoid "boot storm"?

[lofyer]

于 2013/5/26 18:36, lofyer 写道:
> 于 2013/5/26 15:41, Itamar Heim 写道:
>> On 05/26/2013 09:59 AM, Roy Golan wrote:
>>> On 05/24/2013 03:22 PM, Itamar Heim wrote:
>>>> On 05/23/2013 04:23 PM, lofyer wrote:
>>>>> Can host hooks be used to implement the following policy to avoid 
>>>>> "boot
>>>>> storm"?
>>>>>
>>>>> 1.count and sort VMs awaiting for boot.
>>>>> 2.If the count is less than or equal to, for example 5, then boot all
>>>>> VMs and exit the script.
>>>>> 3.Otherwise, boot and dequeue vm0 to vm4, and minus the count by 5.
>>>>> 4.Sleep some time, and go to step 2.
>>>>> _______________________________________________
>>>>> Users mailing list
>>>>> Users at ovirt.org
>>>>> http://lists.ovirt.org/mailman/listinfo/users
>>>>
>>>> hooks run one on vm-start one by one. would be a bit tricky to do the
>>>> above.
>>>> roy - didn't you add some mechanism to throttle boot storms in the
>>>> engine?
>>> yes at RunVmCommandBase.delay(Guid vdsId) - but it doesn't fit here.
>>> It'll delay the VM run only when there is no free memory to run the VM
>>> and will wait till engine signals after gathering statistics of
>>> powering up VMs.
>>
>> lofyer - any other issue other than memory bottleneck you were trying 
>> to resolve?
>>
>> Thanks,
>> Itamar
> I think only cpu_load here. If I start 8 VMs(1G memory each) in a 16G 
> host, it will be very slow for VMs to enter the desktop mode from the 
> time I click "start".
> At first I thought it would be a resolution if I put these boot 
> processes into a linear squence or delay a random period by using hooks.
> Is there an option that I can choose to arrange the boot squence in 
> the engine?
> However, since each VM takes quite a long time to startup, there is no 
> need to do that. Just plug in more CPUs......
Knowing that some other factors will affect it, can I use an SSD as a 
"boot cache"?