On Thu, Jan 25, 2018 at 08:44:00AM -0500, John Stoffel wrote:
That's good to hear! The takeaway I have from this is that NFS over UDP is not something you should ever be using.
Mark> I have chased down the person who set the servers up and he was Mark> trying different options to see what gave the best performance Mark> and left udp in the options as while he wasn't sure that it was Mark> any better it hadn't got any worse.
I'm curious about how they did their testing? And what the cutoff was for making changes and whether it was worth keeping or not. All the docs I've read from Netapp and Oracle say to use NFS over tcp, with large read/write block sizes and then some other options in special cases.
In my mind, the advantages of TCP over UDP even for regular NFS traffic make it a no brainer.
Hmmmm..... disagree.
In the best of all possible worlds UDP wins. Its fast and you can overlap multiple reads and write much easier than TCP. Those guys who invented NFS used it for a reason. If I wanted raw performance I would use UDP.
However, in lots of cases UDP has problems. Network devices are often optimized for TCP (firewalls are a prime example) and as you say packet sizes can be larger with TCP.
I agree that TCP is a better bet in general but I do understand why people may want to use UDP.
Its interesting that the new data transfer algorithms seem to be UDP based. Aspera for example. I wonder if those types of protocols could make sense for NFS?
Regards, pdg