Perfmon Counter of the Week: Logins/Sec

For the second in the series, I’m going to take a look at Logins/Sec.  You get this from SQLServer:General Statistics\Logins\sec.  It has impact on the user experience, as it takes time to set up a connection, and also has impact on the CPU consumption, as documented in Linchi Shea’s excellent blog post on the topic.  It’s important to remember that the stats reported by logins/sec do not include pooled connections

As you might imagine, there’s a direct correlation between logins/sec and transactions hitting the Master database as shown in the graph below.  I scaled them differently to show correlation, because it turns out they overlap otherwise (one login equals one transaction to Master).


You can find some great information on how to tell if connections are pooled or not in James Rowland-Jones blog post here.

There are a number of resources out there to help you figure out and solve issues around connection pooling.    Mohammed Mawla has a good post about the subject, but I think the best succinct advice is from Microsoft:

"To make the best use of connection pooling, explicitly close database connections as soon as possible. By default, a connection terminates after your script finishes execution. However, by explicitly closing a connection in your script after it is no longer needed, you reduce demand on the database server and make the connection available to other users."

Option 4: Third Party Replication (Or: How Stella Got Her Single Copy Cluster Back)

This is the fifth and final post in a series about the various options to achieve HA and DR with Exchange 2010.  In the first, I broke the DAG into its basic components (Active Manager and DAG replication).  In the second, I gave a quick overview of Native DAG.  In the third, I covered a hybrid approach that combined DAG replication and Active Manager for local HA, and array/SAN based replication for remote site recovery.  In the fourth, I described an option that deploys Exchange in a standalone configuration and leverages a hypervisor to achieve local high availability.

This one will cover Exchange’s Third Party Replication.  This one definitely has a lot of cool factor in it.  It actually leverages DAG (in the form of Active Manager) with array or SAN-based replication technology.  You get all the automatic failover, live patching, Exchange-aware coolness of DAG, zero data loss, and you only have to deploy one copy of the data at each site.


Although synchronous operation is possible with both Options 2 and 3, this is the only option shown that combines synchronous replication with automatic failover.

This option will use a plugin from EMC to coordinate the replication engine with Active Manager. This would be either Replication Enabler for Exchange 2010 (free!), or AutoStart 5.3 with the Exchange 2010 module. This option can also use a virtualization platform like Hyper-V or VMware, but a hypervisor is not necessary to leverage the benefits of this option.

Here are the cost factors:

  • Storage: 2
  • Network: 2

Architects and managers will typically consider this option when:

  • Lossless, automatic failover is required
  • Minimal hardware footprint is desired
  • There is minimal latency between the sites
  • A hardware VSS protection scheme is available for rapid recovery in the event of database corruption
  • Live patching is required

Exchange 2010 – Proven on VNX5700/VNX5300

Recently, we released some great new whitepapers for Exchange 2010 proven out on our new EMC VNX series arrays. If you didn’t already see all of the EMC launch buzz around VNX, you can read more about the VNX buzz here.

The VNX series line is EMC’s new unified line replacing the previous CX and Celerra line. A quick overview of the VNX line is below:

Some of the goals of the VNX Exchange 2010 testing was to get our hands on some of the new 2TB NL-SAS drives that we knew would be popular with Exchange customers so large, cheap drives can be used to enable large mailboxes. 2 HA copies via DAGs were also deployed in each of these solutions to enable for some local HA.

First up, the VNX5700 testing where we setup a simulated customer environment of approximately 16,000 mailboxes, 2GB per mailbox, 150 msgs sent/receive (0.15 IOPS) and 2 HA copies for each DB. This was done with the 2TB NL-SAS drives and the hypervisor tested in our case was VMWare vSphere 4.1. Diagram of the test environment looked like this:

In this particular test, we utilized two Vsphere hosts with Active/Passive copies spread out across VMs in each host. In a normal run, the VMs were configured for 2000 mailboxes in a normal run, 4000 in a single failure (2000A, 2000P).

In the whitepaper for this solution, we show you how to do all of the IOPS and capacity calculations manually, but you can obviously use tools like the Exchange Role Calc as well. We also show you how to use a building block approach to scale the solution. In our case, the requirement was for 16,000 mailboxes so we determined in this solution that 16 2TB disks in R10 was the best mix of performance and capacity for each BB. A total of 4 BB was used, so a total of 64 2TB disks (note: this is your performance and DB capacity req’s only, extra disks required for things like snapshot protection, restore LUN etc which we did not show).

To do some performance validation, we did a two hour Jetstress performance test on the four building blocks (32TB). We saw 2,859 Jetstress IOPS against the required 2,400 with all four servers around 14ms read latency, and 3ms write latency. Very good results:

We also wanted to show some of the goodness that comes with our VMWare integration into EMC Unisphere which will provide administrators with great visibility into our vSphere environment:

And on the VNX5300, we did a mix of FC and iSCSI testing to show efficiencies with both types of connectivity knowing that we all like options. We also tested the VNX5300 running on Microsoft Hyper-V (again, we all love options).

In the VNX5300 testing solution, the 4000 user building block was also utilized with a similar 0.15 IOPS per mailbox profile with 2GB mailboxes and also using the 16 2TB NL-SAS drives. Even with 1GB/s iSCSI on our 2 BB testing, Jetstress performance looked very good. In the diagram below you will see where we compared the 2 BB to 1BB to get an idea of the numbers:

As we saw in the testing, iSCSI network utilization moves up to about 70% in the 2 VM test, so this is something that should be considered. We covered some of the iSCSI best practices that we used in our labs in this paper, so please keep those in mind during your planning.

You can read all of the full details on the Exchange 2010 testing with VNX5700 in the Exchange Server 2010 Performance Review with VNX5700 here:

Performance Review for the VNX5300 can be found here:

Until next time,


An Interview with John Moran, EMC Principal Software Engineer for Microsoft Solutions

I recently had the opportunity to talk with John Moran, EMC Principal Software Engineer for Microsoft Solutions.  John is one of EMC’s leading Solutions Engineers focused on validating EMC’s Proven Solutions for Microsoft.  He has recently spent quite a bit of time developing and validating VNX based Unified Solutions for Microsoft applications.


John, how do you see Unisphere and EMC’s new storage platforms making an impact on Microsoft environments?


The Unified platforms, VNX and VNXe, are great for Microsoft environments.  My team has been working on deployment guidelines for Exchange using the new wizard based provisioning the VNXe Unisphere GUI.  We worked with EMC developers to integrate application best practices into the provisioning logic, and they produced a tool that provides storage for your Exchange environment that follows all of our best practices, and is tested to meet Microsoft’s guidelines for deploying either Exchange 2007 or Exchange 2010. 

For SharePoint environments the Unified platform allows you to store data more efficiently.  Using Binary Large Object (BLOB) externalization you can move up to 90% of your SharePoint data into the VNX OE File environment and leverage Nearline SAS drives with compression and deduplication while retaining the quick access times that users expect from your SharePoint metadata.  The Unisphere interface allows you to manage both the BLOB file storage and database block storage from the same place.


John, what is your perspective on how the role of Infrastructure is changing the role of IT?   Do you see a convergence between application IT and infrastructure IT and what does that mean for the cloud?


Customers want things that make their lives easier.  They don’t want to worry about which RAID group a lun is in, and how to break data up between types of storage for optimal performance, they just want it to work.  Unisphere and Unified Storage help you do this by creating a single place to manage storage, and where possible wizard based provisioning to automatically handle best practices letting the administrator be more productive.  From wizard based provisioning to storage pools and automatic tiering with FAST-VP the VNX family of products is designed to just work in the vast majority of situations, and with FAST Cache and FAST-VP to adapt to changing workloads with no administrative effort.  For users that want to manage all the settings themselves you can still do it, but for those who want the system to just work VNX represents a big step forward.

You will be hearing more from John as EMC develops more Microsoft oriented solutions based on VNX.  To learn more about the solutions John referenced above, please click:

             Microsoft Exchange Server 2010 Performance Review Using the EMC VNX5700 Unified Storage Platform – An Architectural Overview


             Technical Documentation: Reference Architecture: EMC Unified Storage for Microsoft Office SharePoint Server 2007 – BLOB Externalization Enabled by EMC Celerra and Metalogix StoragePoint