Hi,
We use VMware+NetApp+Linux. There are 2 ways to install a mission-critical application on the virtual machine:
(1) Install it on a NetApp filer's shared NFS volume connecting to the virtual machine,
(2) Install it on a virtual disk allocated from NetApp filer and assigned to the virtual machine.
Which way is better and why?
Thank you in advance!
I'd suggest going with option (2). NFS can be problematic at times. Not something you want for "mission critical" apps.
This is what I think too. Thanks.
More comments, suggestions and instructions are expected.
I don't think there is a right answer here. It depends on other factors in the environment. Is the appliance strictly network based so even though it's an allocated virtual disk, it still relies on the network? If so, is the appliance in the same subnet as the VMware hosts? What are the performance differences when using NFS or VMware allocated from the appliance? I would guess that the fact that it's a network appliance makes the issue of using NFS or virtual disks moot...so I would go with performance and other issues that may make sense given the environment in making the final choice.
We do it all the time. In fact we have even gone so far as to host the VM OS on the netapp from an NFS mount. Then have NFS mounts to the VM for the application storage. AS long as you have good strong 10g fiber connections we don't see problems with the network fabric.
The problems we typically see are associated with over utilization of the netapp head/cpu/memory when writing to slower disks.
My personal view is to avoid NFS for data. It can be useful for sharing installed software/scripts/application code etc for ease of change control, but the issue there is that you create a dependency on the NFS server. If you have multiple servers operating independently that all use the same application, then you can make one change and update all in one hit, but overall I'm still sceptical You would need to cluster your NFS server for resilience.
It might seem wasteful to some to have separate copies of the same thing, but if you considering reliability as a trade off to cost.
Being British, this is just my two-penneth-worth, naturally.
Robin
I've given thanks to all who replied. Thanks.
NetApp is a most reliable NFS server.
And Linux and Unix are robust NFS clients.
And take into account that the NetApp is tuned for NFS performance - not ISCSI performance.
Some strict procedures must be in place regarding a NetApp maintenance.
E.g. avoid moving to another volume: danger of "stale NFS" handle or otherwise misbehaving NFS clients until they are rebooted.