ESXi 5.1 vMotion migration of VM with 2 vmdk: one on SAN storage and other local storage

[LucasBrasilino]

Hi all:

I've got a two hosts cluster which uses a shared SAN storage where my VM's file are stored. Hosts to storage link is a link aggregation of two 1Gbps

path, and so performing 2Gbps throughput.

Now I need to install a VM which will host our proxy server (Squid). Proxy servers needs a great throughput I/O on its on-disk cache structure. So I'm

considering in somehow deploying it by using two VMDK's. One with with the operating system and softwares, say vm.vmdk file, and the other only for on-disk cache,

say vm-1.vmdk file.

My idea is to put the vm.vmdk file on storage, just like others VM's I've got, and put vm-1.vmdk file on local storage, in order to not depend on 2Gbps link. Let's say

that SAN storage is named 'san_storage', host A local storage is named 'a_local_storage'  and host B local storage is named 'b_local_storage'. So vm.vmdk is

on 'san_storage/vm/vm.vmdk' and is shared to both host A and B. Let's say that VM starts running on host A, so vm-1.vmdk file is 'a_local_storage/vm/vm-1.vmdk'.

I'd like to know is there's a way, by scripting or so, to change the VM configuration in a way that when I do a migration from host A to host B, the second disk of

vm will be disconnected from 'a_local_storage/vm/vm-1vmdk' and will be connected to 'b_local_storage/vm/vm-1.vmdk' when VM starts to run on host B.

I don't want to copy 'vm-1.vmdk' from one host to other, because proxy server can repopulate it.

Is there a way to do it ? Or does anybody has another solution ?

I'm using ESXi 5.1.0 799733 on both hosts with a license that enables vMotion, and using vCenter 5.1.0.5300 Build 947940 to manage them.

regards

Lucas Brasilino

[JagadeeshDev · Accepted solution]

You can use the powercli to edit the vmx configuration file (offline)

[weinstein5]

As JD indicated you should be able to script something with PoweCLI but as heindicated you will have to shut down the VM -

[LucasBrasilino]

Hi JD and WEinstein

Thanks for point it out. I was wondering something in this way. I'll gonna take a look in PowerCli and get it back to discussion here if I get some trouble.

regards

Lucas

[Josh26]

You may want to consider that the technical difficulties you are bringing on yourself around long term management are likely to significantly outweigh any perceived performance gain.

With the majority of Internet downloads these days being youtubes and non-cacheable content like Facebook walls, the usefulness of something like Squid is highly debatable these days too.

[LucasBrasilino]

Josh,

As you might know, Squid is a proxy/cache that implements ACL's, a sort of QoS (delay pools), and so on. So we use it at work not

only for cache.

Nevertheless, about 45% of HTTP requests from my network is served by Squid.  So, It helps a lot Remember that a lot of

Web content fetched (about 90%) are static (CSS, figures, etc).

Thanks.

Lucas