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Day-2 Oerations

Day-2 Operations – vSphere built in vROPS dashboards

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At VMworld I ran a few sessions on Day-2 Operations which I also covered the new built in dashboards for vROPS which were introduced with the fully baked HTML5 client in vSAN/vSphere 6.7.  Many people were not aware of the dashboards and moreso were not aware that these vSAN specific dashboards continue to work even after the 90 day trial period has expired.  Not only that but VMware has done a great job in automating a deployment of vROPS if you have not already got an appliance deployed.  So let’s take a look at these new dashboards in a bit more detail.

Firstly the three vSphere operations Dashboards, the default one that loads up is an overview dashboard of all your clusters:

Then there is the Cluster Level View where you pick a specific cluster:

And finally is the Alerts view…Great timing, I have a physical disk failure in the vSAN Cluster:Now the above three dashboards will no longer be available after the 90 day trial period has expired, and also the link to the vRealize Operations appliance will not be functional either, but after the 90 day trial period has expired, the following three vSAN Dashboards will still be fully functional and available, so let’s look at those in a bit more detail:

The vSAN Overview dashboard, like the vSphere overview dashboard, displays information at a holistic level for all of your vSAN Clusters within this particular vCenter server, you will see that the dashboard provides information on how many clusters are running dedupe/compression, or how many of the clusters are a Stretched Cluster for example.  The dashboard also shows if you need to investigate any current alerts (yes I cleaned up the failed disk before grabbing this screenshot).

The next dashboard we choose a specific cluster to look at in more detail:
In this dashboard we see information pertaining to a specific cluster, we can see that I have 6 critical alerts which we will take a look at next, but there are some key metrics here that from an operational perspective are pretty important from a day-2 operations standpoint:

  • Remaining Capacity
  • Component Limit
  • IOPS, Throughput and Latency statistics
  • Read versus Write latency

The last dashboard is alerts:
Here we can see the current alerts that have been triggered for each cluster which may need to be addressed, the critical alerts previously highlighted in the cluster view were all related to a network redundancy lost when I was troubleshooting packet loss on the physical switch.

So as you can see there’s a really good amount of detail in the vSphere UI relating to vROPS making the day-2 operations a lot easier to perform.

 

 

 

 

Day-2 Oerations

Day-2 Operations – Performance Monitoring in the vSAN UI

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Performance reporting or Performance Monitoring is something of a must in any storage environment today, I remember many times when I was in VMware Support when facing a customer storage performance issue that metrics were not there to capture the event, and most storage performance tools required enabling, obviously this meant that the issue had to be occurring at the time of the performance metrics grab, vSAN in the early days was no different, vSAN Observer whilst being a detailed tool and provided a lot of information, was not a historical tool, it was enabled to troubleshoot a performance issue that was happening at that particular time.

In the later releases of vSAN the UI came equipped with more performance metrics than you could shake a stick at, which from a performance troubleshooting and monitoring perspective is the dogs danglies, but what does this mean from an every day perspective?  Before we take a look at the UI, there are three areas where vSAN Performance metrics can be displayed

  • Cluster level – This is the performance metrics aggregated for the whole cluster and allow you to have the high level view of how your cluster is performing as a whole
  • Host Level – This allows you to look at how vSAN is performing on a host by host perspective and contains further information drilling down through things like Disk Groups, Physical Disks, Network Controllers, VMkernel interfaces.
  • VM Level – This focuses on a specific virtual machine and the objects associated with it.

So what information do we have exactly for a given observation level?  Well let’s first of all take a look at the cluster level performance information, there are three options under the performance tab for vSAN

  • vSAN – Virtual Machine Consumption
  • vSAN – Backend
  • vSAN – iSCSI

I have met many customers that immediately notice there is a big difference between the Virtual Machine Consumption and the Backend graphs, so before we go any further let’s talk about what each of these specific areas mean.

Virtual Machine Consumption
These graphs represent the values that objects residing on the vSAN Datastore are seeing, now remember everything that exists on vSAN is an object, so consumers that are counted in these graphs are Virtual Machines, Stats Objects etc

Backend
These graphs represent the backend disks associated with vSAN, cache and capacity

Both sets of graphs cover the statistics for:

  • IOPS
  • Throughput
  • Latency
  • Congestion
  • Outstanding I/O

iSCSI
The iSCSI Performance graphs contain all the graphs above with the exception of Congestion, these graphs are in relation to each iSCSI Target/LUN created and each one is selected in turn to review the performance graphs associated.

If we move our focus to a host level, in here we have a number of options in addition to the three we also see at a cluster level, however there is some additional metrics we get at a host level for Virtual Machine Consumption and Backend, in the Virtual Machine Consumption graph we have Local Client Cache Hit IOPS and Local Client Cache Hit Rate

And under Backend we also have some additional graphs for Resync IOPS, Resync Throughput and Resync LatencyThe resync metrics are extremely important if vSAN is recovering from a failure of some sort and performing a resync of degraded components, it is also important if you are performing a pro-active rebalance, policy change or a full data migration during host or disk/diskgroup evacuation.

The other options listed under host vSAN performance are:

  • Disk Group – Shows the performance graphs for the disk groups, I will cover this below as this is one of the most interesting set of metrics with a lot of detail.
  • Disk – Shows the physical disks in the host reporting on IOPS, Throughput and  Latency
  • Physical Adapters – Shows the network stats for each vmnic associated with vSAN, stats include Packet Loss Rate which is good for troubleshooting networking issues
  • VMkernel Adapters – Shows the statistics for each VMkernel configured for vSAN, this also includes a Packet Loss Rate which you can then use to troubleshoot the software network stack
  • VMkernel Adapters Aggregation – This is an aggregation of all VMkernel interfaces being used for vSAN on the host

Now let’s go back to the Disk Group performance graphs, as I said earlier this is a very interesting group of metrics to explore, so what do we have in this group?  The first section is all about Frontend (Guest) IOPS, Throughput and Latency

The frontend statistics are maybe as you have guessed already, they are related to vSAN Object I/O being generated from guests running within the vSAN cluster.  If we scroll down a little further we can see statistics relating to Overhead IO,  Read Cache Hit Rate (for hybrid) and Evictions:

Further down we have statistics relating to the vSAN Write Buffer and De-stage rate clearly showing how much of the write buffer is free and also how quickly data is being de-staged from cache to capacity, now we also have resync metrics under disk groups, however this differs slightly against the Cluster Wide Backend statistics, in the disk group graphs we actually have values that represent various aspects of the Resync Operations, the graph differentiates between:

  • Policy Changes
  • Repairs
  • Rebalance

So you can easily distinguish what resync operations are happening by the statistics within the disk group stats.

Collection Interval
The vSAN Performance metrics collect the sample every five minutes, and this is an average over that five minute period, if your cluster is hardly doing anything (like my cluster for the screenshots) then this can throw out some of the latency numbers, in my own cluster I have noticed it shows higher latency when doing practically nothing than it does when I start putting load on the cluster.  I have spoken to many customers about this, it is no concern, it just means that during the collection sample maybe a few “Large” IO operations returned a larger Latency and because of the low number of samples, this skews the average, so no cause for alarm on that one.

Up next will be Day-2 Operations, Performance Monitoring with vROPS, I just have to write it first 🙂

Day-2 Oerations

Day-2 Operations – Health Monitoring

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Health monitoring of an infrastructure is a key element of day to day operations, knowing if something is healthy or unhealthy can make the difference between business impact or remediation steps to prevent any impact ot the business.

There are three ways you can monitor the health of vSAN, the native Health Service which is built into the vSphere UI, vRealize Operations (vROPS), and the API all of which have advantages and disadvantages over the other, for the first part we are going to cover the Health UI which is incorporated into the vSphere UI.

vSAN Health Service
In the current release of vSAN (6.6.1) there are two aspects to the Health Service, an Offline version and an Online version, the Offline version is embedded into the vCenter UI Code and any new features are added to this when patches/releases/updates for vSphere are released.  The Online portion of the Health UI is more dynamic, newer health variables are added as part of the Customer Experience and Improvement Program (CEIP), there is a major advantage to using the Online version in the fact that critical patch releases for vSAN can be alerted through the Health UI which is a really cool feature, it also dynamically adds new alarms to vCenter as part of the health reporting, as VMware understands and gets feedback on how customers are using vSAN, VMware can create alarms dynamically to alert/avoid situations that are a cause for concern.

In order to use the Online portion of the health service you need to opt in to the CEIP program, which is as simple as ensuring your vCenter server has internet capability and you have provided a myvmware account credentials.  A lot of customers are concerned with having their vCenter server having the ability to connect out to the internet, as a workaround I recommend a method where vCenter only has an allowed rule to connect to vmware.com addresses such as a proxy server or white list.

The health service is designed to report on all aspects of vSAN health, and trigger alarms in vCenter to alert you to anything that you should pay attention to, in the previous screenshot, you will notice that I have a warning against the cluster, this is due to the cluster disks not being evenly balanced due to me placing two hosts into maintenance mode to perform firmware updates, as you can see from the screenshot on the right, this has also triggered an alarm in vCenter.

A really cool feature of the Health Service is the “Ask VMware” button, simply highlight an issue and click the button and it will load up a VMware Knowledgebase article telling you what the issue means, why it has occurred and steps to remediate, as many of you know, I come from a support background and spent a good few years in VMware Support so the whole ability to self help and be provided with the right information straight away at the click of a button can be a huge time saver in my opinion.   There is a KB article for every section of the Health Service and as you can see from the screenshot on the left for my disk balance warning,  there is quite a lot of detail in each KB article and the resolution steps are well documented and easy to follow. If after you have followed the steps in the KB and your issue still persists, remember to include in your support request that you have followed the KB Article so you are not asked to run through it again as part of troubleshooting.

When you have deployments such as a 2-Node ROBO or a Stretched Cluster, you do not have to tell the Health Service about this, it will automatically detect and populate the appropriate health checks such as Site to Site latency and witness connectivity.

Critical Patch Updates – The Online Health Service also has the ability to make you aware of a critical patch release, as part of the “Build Recommendations” element of the Health Service, so as a critical patch is released, the online health service will dynamically slip entries into the UI to alert you of the release, in my opinion this is so much better than waiting for an email notification.  The benefit for this is that it can be tailored for your environment, so you are not receiving notifications for updates that are not applicable to your environment.

A question I get quite often is how frequent does the Health Service report, the simple answer is by default it is designed to check the health every 60 minutes, in my environment I have this set to the lowest value which is 15 minutes, however, if there is a critical issue for example, a host failure, network connectivity issue or disk failure then the health service will update with this information pretty instantly, it will not wait for the next refresh cycle and again you will see vCenter alarms triggered for the events.

vRealize Operations
Now I have to admit, I am not a vROPS specialist in any way, shape or form, but I have deployed vROPS in my demo environment and have got the vSAN dashboards operational pretty easily without any challenges.  Now to be clear I am using vROPS 6.6.1 which has the built in native vSAN dashboards which were not present in earlier versions and required you to use the vSAN Storage Management pack to enable the capturing of vSAN Metrics, below is a screenshot showing the default metrics reported in then vSAN Operations Overview dashboard

One immediate advantage that vROPS has over the vSphere UI is that vROPS can display a holistic view of all your vSAN clusters, whereas the vSphere UI is only showing you the status for the cluster that is in focus, so if I had multiple vSAN clusters deployed they would all be listed here in this single dashboard which makes operational life that little bit easier.

You can see there’s a wealth of information at your fingertips from an operational perspective, you can immediately see how your cluster(s) are performing as well as any potential issues that have triggered alarms, which then leads us to the Troubleshooting Dashboard, and here you can immediately see the reason for my 8 “Red” alerts:

As you can see, just like the Operations Overview dashboard, the Troubleshooting dashboard has a lot of information, this dashboard is designed to allow you to drill down into specific areas and components within vSAN, provide you heatmaps on various areas such as disks for example which when a heatmap is red it will draw your attention, for example if I was to double click on one of the green squares in section 9 which is labelled “Is the write buffer full on diskgroups” it will take me to that specific cache disk:

Which takes me to a dashboard specific to that disk group and provides me the following metrics:

As you can see from the above screenshot I can see various important information about my disk group, and if the heatmap was red for this specific disk group I would be able to easily see why based on the metrics presented to me, in my case my disk group is healthy.

There is another dashboard in vROPS called Capacity Overview which I will cover on another Day-2 Operations post based around capacity reporting, so watch out for that one.

So as you can see there are immediately advantages and disadvantages of using the Health Service over vROPS and vice versa, in my opinion I think both tools are important in day to day operations and being able to use both tools provides you with the toolset to effectively manage your environments easier.