Watch this Ask the Expert session to learn about configuration and tuning guidelines to address potential issues with thin provisioning, NUMA reach, stability and performance.
Watch the Webinar
You will learn:
- Basic operations of VMware, and its hypervisor and cluster management.
- Pros and cons of running a thick application like SAS in a virtual environment.
- Performance challenges of hypervisor-controlled and highly shared systems.
- Infrastructure advice for configuring SAS on VMware.
- Performance tuning advice for SAS on VMware.
The questions from the Q&A segment held at the end of the webinar are listed below and the slides from the webinar are attached.
Q&A
Our VMWare Team has standard VM farm host definitions, how do we work around that if they aren’t appropriate for SAS?
The best way to do that is to schedule a call with your VM administrator, and either myself or Margaret Crevar, from our SAS Performance Lab, and we're very happy to help you have that conversation with your VM administrator. We can determine what their commodity farm definitions are and determine what effect they may have on your performance. To manage their farm as best they can, we often request what's called “exceptions”, which means that they'll go out of the normal VM definitions that they generally set up. We may have to have them more thickly provision hosts resources, change adapter types, or change some of the host settings. They typically do not like to do this because it can take them out of VM standard definitions which can interfere with automated management and maintenance. But we'll typically work with them to do that if performance is so key to this particular application in the company, that it's required to make it run well. We're adept at having those conversations and reaching a compromise with them to get you the best performance you can. So, we're happy to help with that.
What can we do about storage shared with other applications?
You can have a discussion with your storage administrator, and you may get some ameliorations or considerations from them, or you may not, because storage is very expensive and highly shared. A storage array can cost a million dollars or more, and it's typically a large, shared device. Storage Admins have to configure storage to best fit a multi-application profile, and that can sometimes water down bandwidth for performance hungry applications. Storage administrators are very proficient at doing this, and they know how to configure storage to make the maximum use of it, that may or may not work out in your favor for performance. If storage is not dedicated to SAS VMS you may encounter “noisy neighbors”, or actually be one.
We can elaborate for your storage team what the capacity and bandwidth requirements are for SAS. They can use this information to determine if they can provision those needs out of existing shared storage. If they cannot, a decision needs to be made about dedicated storage. Again, we can help with that discussion.
Can you help us explain these needs to our VMWare Team?
Absolutely. We have a VMware Best Practices Guide and a VMware Checklist that is available from SAS Technical Support (external links will be coming soon). This can be given the VM administrators. Whenever we work on, for example, a SAS Tech Support ticket where involving VMWare or if a customer is installing a new SAS system , or moving a SAS System from bare-metal to VMware, we'll provide this checklist to the administrators. They'll look at it. Sometimes they can’t abide by the best practices because they don’t have the resources to thickly provision the hardware, and it causes extra maintenance cycles. But if they understand that this business application set crucial to the revenue of the company, they'll make these ameliorations and they will find compromises to make it work. We've often had some VM administrator realize it is easier standing up some bare metal machines rather than trying to squeeze thickly provisioned VMs into a commodity farm. We can have that conversation and we can help push it in the right direction.
How is VMware/ Virtualization used in Cloud environments in SAS?
That's a really broad topic and that's probably something that if you really want to go into that in depth, schedule a meeting with myself personally and I'll be happy to have a conference call with you. But we'll touch on it briefly here. VMware has an entire cloud foundry product set for cloud and multi-cloud managmeent. Be aware that cloud vendors like Google, Azure, and Amazon provide their own host hypevisors for cloud management. When you introduce VMware to that environment, now you're running another virtual management system. This all functions very well and VM has great cloud products. We have not interfaced a tremendous amount with VMware in the cloud. To this state, most of the people are pretty much sticking with the hypervisors that either come with Amazon or Azure, for example. If they decide to install VM Cloud Management, they will need to work closely with VMWare, and we can help answer any software/application performance and workload questions to help guide their decision making.
How can we ensure the saswork throughput requirements with WMware environments?
SASWORK performance is a result of how you physically construct your file systems, and that often depends upon striping. Virtual machine disks (VMDK) are single Lun entities. For each SAS process, we employ one writer thread per Lun, and multiple reader threads. So, each Lun has 1 writer thread. If that one Lun that they gave you that VMDK disk is on a widely striped large storage array, it's generally not going to be a problem to use VMDKs. It's going to perform like gangbusters. If the underlying construction of tuning of that LUN is insufficient for your workload, you will need to stripe across multiple LUNs/VMDKs to obtain multiple writers to parallelize your SAS workload. I work a lot with VM Ware and striping VMDKS and creating host logical volume mounts for VMDKS. Both Red Hat and I do this every day in the field and we're happy to have that conversation with you and teach you how to do that very performantly.
Recommended Resources
What is VMware? What is it Used for?
What is a Hypervisor?
VMware: An Essential Guide
Moving from SAS®9 to SAS® Viya®
Move to Viya Board
Please see additional resources in the attached slide deck.
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