How to setup fake raid for vmware virtual machines?

Question

I was wondering about the proper way to store state between sequence invocations in WSO2ESB. In other words, if I have a scheduled task that invokes sequence S, at the end of iteration 0 I want to store some String variable (lets' call it ID), and then I want to read this ID at the start (or in the middle) of iteration 1, and so on.

To be more precise, I want to get a list of new SMS messages from an existing service, Twilio to be exact. However, Twilio only lets me get messages for selected days, i.e. there's no way for me to say give me only new messages (since I last checked / newer than certain message ID). Therefore, I'd like to create a scheduled task that will query Twilio and pass only new messages via REST call to my service. In order to do this, my sequence needs to query Twilio and then go through the returned list of messages, and discard messages that were already reported in the previous invocation. Now, to do this I need to store some state between different task/sequence invocations, i.e. at the end of the sequence I need to store the ID of the newest message in the current batch. This ID can then be used in subsequent invocation to determine which messages were already reported in the previous invocation.

I could use DBLookup and DB Report mediators, but it seems like an overkill (using a database to store a single string) and not very performance friendly. On the other hand, as far as I can see Class mediators are instantiated as singletons, therefore I could create a custom Class mediator that would manage this state and filter the list of messages to be sent to my service. I am quite sure that this will work, but I was wondering if this is the way to go, or there might be a more elegant solution that I missed.

Solution 1

ESXi is not supporting fake raid. You need to create 2 VMFS and add 2 disk each on one of the data stores and setup software RAID on the guest OS. You will have redundancy for VM, but not for ESX itself.

Solution 2

You should use supported hardware. Fakeraid solutions aren't in the scope of VMWare ESXi blessed setup. You can make things work by acquiring a hardware RAID controller from the VMWare Hardware Compatibility List, though.

Comments

[jM2.me]

I must of been tired when posting this questions but I should clear something out. The questions is about setting up fakeraid for virtual machine or guest-os.

[ravi yarlagadda]

If you go this route, another option would be to expose the disks to a VM as raw block devices (instead of adding the extra VMFS layer) with vmkfstools --createrdmpassthru.

[jM2.me]

Sorry for late reply but this is what worked for me. Thank you Mircea and Shane

[Jean-Michel]

I've had a look to this documentation but can't figure how to persist properties in registry... cannot even find the word 'registry' in that page. Could you add a sample in your answer ?

[Plain Ol' Human]

Same here, couldn't find a word about the registry in that documentation. As far as I can tell, property mediator work only with the message context, therefore any properties it sets can live only until the response is sent back to the client (or even less depending on the chosen scope).

[Plain Ol' Human]

Thanks a million. Although I guess I should ensure thread safety for the state. I suppose it could work fine if the state is just a string, but in general, if the state is more complex, some synchronization is probably in order. Or does the framework makes any guarantees that the mediate method will not be executed by more than one thread in parallel?