Hi, According to some (possibly old) documentation I read, I have the impression that it is *optional* to define a secondary storage IP subnet.
Note, my questions are all in the context of: - CloudStack 4.2 - ESXi hosts / vSphere 5.1 - Primary Storage is VMFS via fiber channel - Advanced Networking Here is the document to which I am referring, along with the relevant quotes: CloudStack System VMs: https://cwiki.apache.org/confluence/download/attachments/30149076/Cloudstack+System+VMs.pdf *"Network Terminology -> Storage: As it relates to CloudStack, this is an optional network dedicated to secondary storage. If not specified, the management network will be assumed for this role."* *"SSVM -> eth3 (storage): Note if a physical storage interface was not specified when creating the zone this interface will not exist. Storage traffic will assume the management interface"* My Questions: 1. Is the above-referenced document accurate for CloudStack 4.2? 2. Do I interpret correctly that I don't need to define an IP subnet for Secondary Storage? 3. I have noticed that the CloudStack 4.2 Installation Guide, section 2.8.3 "Advanced Zone Network Traffic Types", for the type "Storage" says: *"You must configure the IP range to use for the storage network."* http://cloudstack.apache.org/docs/en-US/Apache_CloudStack/4.2.0/html-single/Installation_Guide/index.html#advanced-zone-network-traffic-types How am I to interpret the quoted statement? Is it saying that I must configure a range regardless, or only if I *opt* to have a Secondary Storage network? If there is no Secondary Storage IP subnet, would I enter a range selected from the Management IP subnet? I am aware of the redundancy and performance benefits to using separate interfaces, this is not my concern here. My idea is to have a simplified CloudStack architecture by using a single IP subnet for CloudStack Management, and putting the NFS server on the same subnet (NFS to be used for Secondary Storage only). If your response is that a defined Secondary Storage IP subnet is a mandatory requirement, then I have a few other questions regarding this network: 4. I haven't found any documentation that helps with planning the size of the Secondary Storage network -- besides the NFS server and the SSVM, what other devices must have an IP address on this network? 5. How are IP addresses for devices on the Secondary Storage network assigned? In the case of the SSVM it must be dynamic, but if I were to manually put a CloudStack host onto this network (for convenience), what assures that the same IP address won't also get handed out to an SSVM? 6. Is it permitted to place the Secondary Storage traffic onto its own dedicated vSwitch on ESXi? According to the Installation Guide under section 8.3.5.1.1 Separating Traffic: "*CloudStack allows you to use vCenter to configure three separate networks per ESXi host. *...* The allowed networks for configuration are public, guest, and private (for management and usually storage traffic).*" This would suggest that storage traffic must share the same vSwitch as management traffic. If I am missing something fundamental, and/or asking the wrong questions, please correct me! Same goes if you have some general insight into the pros and cons of having a Secondary Storage IP subnet. Many thanks! Rob
