I have a question regarding allocating resources for SQL Server 2008 R2. We a have physical server Windows 2008 R2 with three installations of SQL Server 2008 R2 for Production, test and development. The server has 64GB of RAM and 24 cores. If we want to allocate specific amount of resources to specific instance, can we do it? For instance, we want allocate 32 GB and 12 cores for production instance, and 12 GB and 6 cores each for test and development.
Because all three instances are on the same physical server, we do not want the test and development instances to consume more resources than we want them to. Is there a way to set it in the server or in SQL Server?
You have some options. The three options I see are:
(1) use a VM for each server on the same physical machine and allocate resources to the VMs as you see fit.
(2) use sql server resource governor (http://blog.sqlauthority.com/2012/06/04/sql-server-simple-example-to-configure-resource-governor-introduction-to-resource-governor/)
With this you can setup resource consumption by user. So for your test server, just setup its users with a lower resource allocation.
(3) in sql server you can also set the max memory of an instance in sys.configurations using sp_configure. For CPU you could try experimenting with affinity mask in a test environment or assigning a specific CPU id range or NUMA node id range to the instance. For more details: http://msdn.microsoft.com/en-us/library/ee210585(v=sql.110).aspx
I would recommend always setting max server memory in any instance. I would not recommend messing with the affinity or CPU range settings without a lot of testing. Instead, for your case I would recommend using resource governor. This is bc it does not have the drawback of VMs, which themselves have overhead and thus use up some server resources. Also you can leave the CPU scheduling to the OS and server with resource governor. This option also gives you the most flexibility since you can limit resources by specific user, in case you ever need that.
Related
I'm going through the list of perf improvements that can be made against Cosmos DB. My APIs are hosted in a Function app in consumption mode. Is turning on gcServer recommended for Azure Functions?
There is more information on gcServer here.
For single-processor computers, the default workstation garbage
collection should be the fastest option. Either workstation or server
can be used for two-processor computers. Server garbage collection
should be the fastest option for more than two processors. Most
commonly, multiprocessor server systems disable server GC and use
workstation GC instead when many instances of a server app run on the
same machine.
How many processors run in an active instance in a consumption plan?
How many processors run in an active instance in a consumption plan?
Each instance of the Functions host in the Consumption plan is limited to 1.5 GB of memory and one CPU. So there is only 1 processor for that. For more details, you can refer to this article.
Our ASP.NET app uses a component that is licensed by the number of processor cores. Unfortunately, our customer wants to deploy the app onto a multi-function server (IIS, SQL Server, file server, etc.) that exceeds the number of processor cores for which the customer is licensed: they are allowed four cores but have two processors with four cores each. I configure IIS to use only one processor?
so i tried to set application pools settings
in applicationpool ->advance setting -> process affinity enable =ture
and i have set number of working process =1
after i have checked in tast manager w3wp.exe-> set affinity its all core are selected
where i made error...
thank u
I am limited by a piece of software that utilizes a single core per instance of the program run. It will run off an SQL server work queue and deposit results to the server. So the more instances I have running the faster the overall project is done. I have played with Azure VMs a bit and can speed up the process in two ways.
1) I can run the app on a single core VM, clone that VM and run it on as many as I feel necessary to speed up the job sufficiently.
OR
2) I can run the app 8 times on an 8-core VM, ...again clone that VM and run it on as many as I feel necessary to speed up the job sufficiently.
I have noticed in testing that the speed-up is roughly the same for adding 8 single core VMs and 1 8-core VM. Assuming this is true, would it better better price-wise to have single core machines?
The pricing is a bit of a mystery, whether it is real cpu usage time, or what. It is a bit easier using the 1 8-core approach as spinning up machines and taking them down takes time, but I guess that could be automated.
It does seem from some pricing pages that the multiple single core VM approach would cost less?
Side question: so could I do like some power shell scripts to just keep adding VMs of a certain image and running the app, and then start shutting them down once I get close to finishing? After generating the VMs would there be some way to kick off the app without having to remote in to each one and running it?
I would argue that all else being equal, and this code truly being CPU-bound and not benefitting from any memory sharing that running multiple processes on the same machine would provide, you should opt for the single core machines rather than multi-core machines.
Reasons:
Isolate fault domains
Scaling out rather than up is better to do when possible because it naturally isolates faults. If one of your small nodes crashes, that only affects one process. If a large node crashes, multiple processes go down.
Load balancing
Windows Azure, like any multi-tenant system, is a shared resource. This means you will likely be competing for CPU cycles with other workloads. Having small VMs gives you a better chance of having them distributed across physical servers in the datacenter that have the best resource situation at the time the machines are provisioned (you would want to make sure to stop and deallocate the VMs before starting them again to allow the Azure fabric placement algorithms to select the best hosts). If you used large VMs, it would be less likely to find a suitable host with optimal contention to accommodate many virtual cores.
Virtual processor scheduling
It's not widely understood how scheduling a virtual CPU is different than scheduling a physical one, but it is something worth reading up on. The main thing to remember is that hypervisors like VMware ESXi and Hyper-V (which runs Azure) schedule multiple virtual cores together rather than separately. So if you have an 8-core VM, the physical host must have 8 physical cores free simultaneously before it can allow the virtual CPU to run. The more virtual cores, the more unlikely the host will have sufficient physical cores at any given time (even if 7 physical cores are free, the VM cannot run). This can result in a paradoxical effect of causing the VM to perform worse as more virtual CPU cores are added to it. http://www.perfdynamics.com/Classes/Materials/BradyVirtual.pdf
In short, a single vCPU machine is more likely to get a share of the physical processor than an 8 vCPU machine, all else equal.
And I agree that the pricing is basically the same, except for a little more storage cost to store many small VMs versus fewer large ones. But storage in Azure is far less expensive than the compute, so likely doesn't tip any economic scale.
Hope that helps.
Billing
According to Windows Azure Virtual Machines Pricing Details, Virtual Machines are charged by the minute (of wall clock time). Prices are listed as hourly rates (60 minutes) and are billed based on total number of minutes when the VMs run for a partial hour.
In July 2013, 1 Small VM (1 virtual core) costs $0.09/hr; 8 Small VMs (8 virtual cores) cost $0.72/hr; 1 Extra Large VM (8 virtual cores) cost $0.72/hr (same as 8 Small VMs).
VM Sizes and Performance
The VMs sizes differ not only in number of cores and RAM, but also on network I/O performance, ranging from 100 Mbps for Small to 800 Mbps for Extra Large.
Extra Small VMs are rather limited in CPU and I/O power and are inadequate for workloads such as you described.
For single-threaded, I/O bound applications such as described in the question, an Extra Large VM could have an edge because of faster response times for each request.
It's also advisable to benchmark workloads running 2, 4 or more processes per core. For instance, 2 or 4 processes in a Small VM and 16, 32 or more processes in an Extra Large VM, to find the adequate balance between CPU and I/O loads (provided you don't use more RAM than is available).
Auto-scaling
Auto-scaling Virtual Machines is built-into Windows Azure directly. It can be based either on CPU load or Windows Azure Queues length.
Another alternative is to use specialized tools or services to monitor load across the servers and run PowerShell scripts to add or remove virtual machines as needed.
Auto-run
You can use the Windows Scheduler to automatically run tasks when Windows starts.
The pricing is "Uptime of the machine in hours * rate of the VM size/hour * number of instances"
e.g. You have a 8 Core VM (Extra Large) running for a month (30 Days)
(30 * 24) * 0.72$ * 1= 518.4$
for 8 single cores it will be
(30 * 24) * 0.09 * 8 = 518.4$
So I doubt if there will be any price difference. One advantage of using smaller machines and "scaling out" is when you have more granular control over scalability. An Extra-large machine will eat more idle dollars than 2-3 small machines.
Yes you can definitely script this. Assuming they are IaaS machines you could add the script to windows startup, if on PaaS you could use the "Startup Task".
Reference
When I run a worker role instance on Azure, is it a complete VM running in a shared host (like EC2)? Or is it running in a shared system (like Heroku)?
For example, what happens if my application starts requesting 100 GB of memory? Will it get killed off automatically for violation of limits (รก la Google App Engine), or will it just exhaust the VM, so that the Azure fabric restarts it?
Do two roles ever run in the same system?
It's a whole VM, and the resources allocated are based directly on the size of VM you choose, from 1.75GB (Small) to 14GB (XL), with 1-8 cores. There's also an Extra Small instance with 768MB RAM and shared core. Full VM size details are here.
With Windows Azure, your VM is allocated on a physical server, and it's the fabric's responsibility of finding such servers to properly allocate all of your web or worker role instances. If you have multiple instances, this means allocating these VMs across fault domains.
With your VM, you don't have to worry about being killed off if you try allocating too much in the resource dep't: it's just like having a machine, and you can't go beyond what's there.
As far as two roles running on the same system: Each role has instances, and with multiple instances, as I mentioned above, your instances are divided into fault domains. If, say, you had 4 instances and 2 fault domains, it's possible that you may have two instances on the same rack (or maybe same server).
I ran a quick test to check this. I'm using a "small" instance that has something like 1,75 gigabytes of memory. My code uses an ArrayList to store references to large arrays so that those arrays are not garbage collected. Each array is one billion bytes and once it is allocated I run a loop that sets each element to zero and then another loop to check that each element is zero to ensure that memory is indeed allocated from the operating system (not sure if it matters in C#, but it indeed mattered in C++). Once the array is created, written to and read from, it is added to the ArrayList.
So my code successfully allocated five such arrays and the attempt to allocate the sixth one resulted in System.OutOfMemoryException. Since 5 billion bytes plus overhead is definitely more that 1,75 gigabytes of physical memory allocated to the machine I believe this proves that page file is enabled on the VM and the behavior is the same as on usual Windows Server 2008 with the limitations induced by the machine where it is running.
I need to run 8-10 instances of my application on IIS 6.0 that are all identical but point to different backends (handled via config files, which would be different for each virtual directory). I want to create multiple virtual directories that point to different versions of the app and I want to know if there is any significant performance penalty for this. The server (Windows Server 2003) is a quad-core with 4 GB of ram and the single install of the app barely touches the CPU or memory, so it doesn't seem to be a concern. This doesn't seem to justify another server, especially since some of the instances will be very lightly used. Obviously, performance depends on the server and the application, but are there any concerns with this situation?
IIS on Windows Server 2003 is built to handle lots of sites, so the number of sites itself is not a concern. The resource needs of your application is much more of a factor. I.e., How much, i/o, cpu, threads, database resources does it consume?
We have a quad-core Windows Server 2003 server here handling several hundred sites no problem. But one resource-intensive app can eat a whole server no problem.
If you find your application is cpu bound, you can put each instance in its own application pool and then limit the amount of cpu each pool can use, so that no one instance can bottleneck any of the others.
I suggest you add a few at a time and see how it goes.
No concerns. If you run into any performance issues, it won't be with IIS for 10 apps that size.
You should consider using multiple application pool. If you do that, and the cpu, memory, IO and network resources of the server are in order. Then there is no performance issue.
It is possible to run them all on the same application pool. But then add to the list, thread pool usage issue, because all application will use one thread pool, and if it is 32 bit server Then there is a limit( around 1.5 Gb ) for the w3wp process.
We constantly run 15-20 per server on a 10 server load balanced farm. We don't come across any issues
The short answer is no, there should be no concerns.
In effect, you are asking if IIS can host 8 - 10 websites... of course it can. Perhaps, you might want to configure it as individual websites rather than virtual directories, and perhaps with individual application pools so that each instance is entirely independent.
You mention that these aren't vary demanding applications; assuming they aren't all linking into the same Access database, I can't see any problems.