Let your storage array do the heavy lifting with VAAI!
I’ve seen a few blogposts recently about storage features in vSphere5 and plenty of forum discussions about the level of support from various vendors but none that specifically address the Netapp world. As some of these features require your vendor to provide plugins and integration I’m going to cover the Netapp offerings and point out what works today and what’s promised for the future.
Many of the vSphere5 storage features work regardless of your underlying storage array, including StorageDRS, storage clusters, VMFS5 enhancements (provided you have block protocols) and the VMware Storage Appliance (vSA). The following vSphere features however are dependent on array integration;
- VAAI (the VMware Storage API for Array Integration). If you need a refresher on VAAI and what’s new in vSphere v5 check out these great blogposts by Dave Henry - part one covers block protocols (FC and iSCSI), part two covers NFS. The inimitable Chad Sakac from EMC also has a great post on the new vSphere5 primitives.
- VASA (the VMware Storage API for Storage Awareness). Introduced in vSphere5 this allows your storage array to send underlying implementation details of the datastore back to the ESXi host such as RAID levels, replication, dedupe, compression, number of spindles etc. These details can be used by other features such as Storage Profiles and StorageDRS to make more informed decisions.
The main point of administration (and integration) when using Netapp storage is the Virtual Storage Console (VSC), a vCenter plugin created by Netapp. If you haven’t already got this installed (the latest version is v4, released March 16th 2012) then go download it (NOW account required). As well as the vCenter plugin you must ensure your version of ONTAP also supports the vSphere functionality – as of April 19th 2012 the latest release is ONTAP 8.1. You can find out more about its featureset from Netapp’s Nick Howell. As well as the core vSphere storage features the VSC enables some extra features;
These features are all covered in Netapp’s popular TR3749 (best practices for vSphere, now updated for vSphere5) and the VSC release notes.
Poor old NFS – no VAAI for you…
It all sounds great! You’ve upgraded to vSphere5 (with Enterprise or Enterprise Plus licensing), installed the VSC vCenter plugin and upgraded ONTAP to the shiny new 8.1 release. Your Netapp arrays are in place and churning out 1′s and 0′s at a blinding rate and you’re looking forward to giving vSphere some time off for good behaviour and letting your Netapp do the heavy lifting…..
The VCAP5-DCA exam is a tough nut to crack and will probably consume quite a bit of your time in study and practice (unless you’re a VMware PSO in which case you probably do this stuff all day every day!). Before you get stuck into the blueprint objectives there are some things you should do to prepare;
- Get access to a lab. There are numerous options;
- Build your own whitebox lab at home
- Use spare equipment at your work.
- Rent VCAP-DCA specific lab space on a weekly basis. There are a few of these popping up although I’ve not tried them myself – Optism Training, YourLabTime. You get enterprise grade equipment but at £120p/w upwards a home lab might be the more affordable option….
- Once you’ve got your lab, have a look at AutoLab by @demitassenz. It helps you quickly build a base lab.
- Download the official vSphere5 documentation (there’s a link at the bottom of the page to download a .ZIP of all docs combined). I’d recommend using the Xtravirt documentation downloader as it simplifies the process. Make sure you have the docs to hand as you’ll want to refer to them often.
- Gather additional study materials. This will depend on your budget but I’d recommend;
- Plan your study time. There are 26 objectives so work out how much time you have until you want to sit the exam and work backwards. Be aware of your strengths – some sections you’ll cruise through while you may need to spend longer on the topics you’re less familiar with.
- Book the exam (through Pearson Vue). This may not work for everyone but many people work better with a deadline to adhere to. You can always move the booking provided you do so at least 24 hours before the day. Pick a date which gives you a suitable time to prepare.
- Get involved in social media – the VMTN community forums, Twitter, read and comment on blogs etc. As you’ll see from my study notes a good chunk of the material comes from these sources and having people to answer questions is one of the best ways to confirm your understanding.
Now dive into your studies and good luck!
As with all my VCAP5-DCA study notes, the blogposts only cover material new to vSphere5 so make sure you read the v4 study notes for section 1.1 first. When published the VCAP5-DCA study guide PDF will be a complete standalone reference.
- Identify RAID levels
- Identify supported HBA types
- Identify virtual disk format types
Skills and Abilities
- Determine use cases for and configure VMware DirectPath I/O
- Determine requirements for and configure NPIV
- Determine appropriate RAID level for various Virtual Machine workloads
- Apply VMware storage best practices
- Understand use cases for Raw Device Mapping
- Configure vCenter Server storage filters
- Understand and apply VMFS resignaturing
- Understand and apply LUN masking using PSA-related commands
- Analyze I/O workloads to determine storage performance requirements
- Identify and tag SSD devices
- Administer hardware acceleration for VAAI
- Configure and administer profile-based storage
- Prepare storage for maintenance (mounting/un-mounting)
- Upgrade VMware storage infrastructure
Tools & learning resources
With vSphere5 having been described as a ‘storage release’ there is quite a lot of new material to cover in Section1 of the blueprint. First I’ll cover a couple of objectives which have only minor amendments from vSphere4.
Determine use cases for and configure VMware DirectPath I/O
The only real change is DirectPath vMotion, which is not as grand as it sounds. As you’ll recall from vSphere4 a VM using DirectPath can’t use vMotion or snapshots (or any feature which uses those such as DRS and many backup products) and the device in question isn’t available to other VMs. The only change with vSphere5 is that you can vMotion a VM provided it’s on Cisco’s UCS and there’s a supported Cisco UCS Virtual Machine Fabric Extender (VM-FEX) distributed switch. Read all about it here – if this is in the exam we’ve got no chance!
Identify and tag SSD devices
This is a tricky objective if you don’t own an SSD drive to experiment with (although you can workaround that limitation). You can identify an SSD disk in various ways;
- Using the vSphere client. Any view which shows the storage devices (‘Datastores and Datastore clusters view’, Host summary, Host -> Configuration -> Storage etc) includes a new column ‘Drive Type’ which lists Non-SSD or SSD (for block devices) and Unknown for NFS datastores.
- Using the CLI. Execute the following command and look for the ‘Is SSD:’ line for your specific device;
esxcli storage core device list
Tagging an SSD should be automatic but there are situations where you may need to do it manually. This can only be done via the CLI and is explained in this VMware article. The steps are similar to masking a LUN or configuring a new PSP;
- Check the existing claimrules
- Configure a new claim rule for your device, specifying ‘ssd_enable’
- Enable to new claim rule and load it into memory
So you’ve identified and tagged your SSD, but what can you do with it? SSDs can be used with the new Swap to Host cache feature best summed up by Duncan over at Yellow Bricks;
“Using “Swap to host cache” will severely reduce the performance impact of VMkernel swapping. It is recommended to use a local SSD drive to eliminate any network latency and to optimize for performance.”
As an interesting use case here’s a post describing how to use Swap to Host cache with an SSD and laptop – could be useful for a VCAP home lab!
The above and more are covered very well in chapter 15 of the vSphere5 Storage guide.
IT is a fast moving industry, and the current shift to cloud computing is accelerating the rate of change. With the forthcoming release of the vSphere5 VCAP exams (VCAP5-DCA and the VCAP5-DCD) I’ve been planning to study my socks off to get both exams under my belt. I’m sure I’m not alone in struggling to make study time, particularly as my day job doesn’t tend to cover all of the material either because we’re only Enterprise level licensing or because we don’t use all the features. On top of that I’d like to update my VCAP-DCA study guide which will consume a significant chunk of time.
This serious case of study contention has made me revisit my priorities. The VMware ecosystem has evolved considerably over the last few years and there’s considerable buzz around VMware View and vCloud Director (not to mention the whole Cloud Foundry and vFabric ecosystem). Maybe these would be better areas to focus on? As John Troyer said about certifications “You don’t have to collect them all!” but it does make me wonder – which VMware certs are most likely to benefit career progression?
VCP or VCAP?
First some facts. The VMware platform which evolved into vSphere was launched in 2001, the first VCP exam was available in June 2003 (@susangude is VCP#1), and the first VCAP exams were launched seven years later in August 2010. Nine years on and the statistics are well known – around 60,000 VCPs worldwide and approximately 600 certified in each of the two VCAP tracks (so 50 VCPs for every VCAP!).
Categories: VCAP, Virtualisation, VMware certification, desktop virtualisation, VCAP, VCAP-DCA, VCAP-DCD, vcdx, vcp-dt, vExpert, vsphere5