SANLess Clustering Archives - SIOS SANless clusters

Remove The Weakest Link, Ensure High Availability Cluster Configuration

January 21, 2018 by Jason Aw Leave a Comment

Build A High Availability Cluster Configuration

When we build a High Availability Cluster Configuration, your application availability is only as good as its weakest link. What this means is that if you bought great servers with redundant everything (CPU, fans, power, RAID, RAM, etc) and a super deluxe SAN with multi-path connectivity. Coupled with multiple SAN switches and clustered your application with your favorite clustering software. You probably have a very reliable application – right? Well, not necessarily. Are the servers plugged into the same UPS? Are they on the same network switch? Are they cooled by the same AC unit? Are they in the same building? Is your SAN truly reliable? Any one of these issues among others is a single point of failure in a High Availability Cluster Configuration.

Seek And Remove The Weakest Link in Cluster Configuration

Of course, you have to know when “good enough” is “good enough”. Your budget and your SLAs will help decide what exactly is good enough. However, one area where I am concerned that people may be skimping is in the area of storage. With the advent of cheap or free iSCSI target software solutions, I am seeing some people recommend that you just throw some iSCSI target software on a spare server and voilà – instant shared storage.

Mind you I’m not talking about OEM iSCSI solutions that have built in failover technology and/or other availability features; or even storage virtualization solutions such as FalconStor. I’m talking about the guy who has a server running Windows Server 2008 that he has loaded up with storage and wants to turn it into an iSCSI target. This is great in a lab. But if you are serious about HA, you should think again. Even Microsoft only provides their iSCSI target software to qualified OEM builders experienced in delivering enterprise class storage arrays.

What You Are Actually Getting?

First of all, this is Windows. Not some hardened OS built to only serve storage. It will require maintenance, security updates, hardware fixes, etc. It basically has the same reliability as the application server you are trying to protect. Does it make sense to cluster your application servers. Yet use the same class of server and OS to host your storage? You basically have moved your single point of failure away from your application server and moved it to your storage server. It’s not a smart move as far as I am concerned.

Some of the Enterprise Class iSCSI target software includes synchronous and/or asynchronous replication software and snapshot capabilities. This functionality certainly helps in terms of your recovery point objective (RPO). Although it won’t help your recovery time objective (RTO) unless the failover is automatic and seamless to your clustering software. Let’s say the primary iSCSI storage array fails in the middle of the night. Who is going to be there to activate the replicated copy? You may be down for quite some time before you even realize there is a problem. Again, this may be “good enough”; you just need to be aware of what you are signing up for. Is that the High Availability Cluster Configuration you’re seeking?

SIOS DataKeeper

One thing you can do to improve the reliability of your iSCSI target server is to use a replication product such as SteelEye DataKeeper Cluster Edition to eliminate the single point of failure. Let me illustrate.

Figure 1 – Typical Shared Storage Configuration. In the event that the iSCSI target becomes unavailable, all the nodes go offline.

If we take the same configuration shown above and add a hot standby iSCSI target using SteelEye DataKeeper Cluster Edition to do replication AND automatic failover, you have just given you iSCSI target solution a whole new level of availability. That solution would look very much like this.

DataKeeper Cluster Edition - High Availability Cluster Configuration — Figure 2 – In this scenario, DataKeeper Cluster Edition is replicating the iSCSI attached volume on the active node to the iSCSI attached volume on the passive node, which is connected to an entirely different iSCSI target server.

The key difference in the solution which utilizes SteelEye DataKeeper Cluster Edition vs. replication solutions provide by some iSCSI target vendors is in the integration with WSFC. The question to ask of your iSCSI solution vendor is this…

What happens if I pull the power cord on the active iSCSI target server?

If the recovery process is a manual procedure, it is not a true HA solution. But what if it is automatic and completely integrated with WSFC? Then you have a much higher level of availability and have eliminated the iSCSI array as a single point of failure.

Chat with us to also achieve High Availability Cluster Configuration

Reproduced with permission from Clusteringformortals.

Yes, You Can Have a SQL Server Cluster in VMware without Raw Device Mapping

June 4, 2015 by Tony Tomarchio Leave a Comment

As companies look to move SQL Server to VMware environments, they soon face the challenge of how to provide high availability protection. The problem is that Windows Server Failover Clustering requires shared storage, so in VMware environments you need to use Raw Device Mapping to give VMs direct access to the SAN. RDM limits your ability to use important VMware features such as vMotion, snapshots, and Virtual Consolidated Backup.

A simple solution is to add SANLess clustering software, such as SIOS DataKeeper Cluster Edition, to your WSFC. It uses efficient block level replication to synchronize local storage to appear to WSFC as a shared disk without the need for RDM. You get high availability protection without sacrificing VMware features, flexibility or performance.

I discussed this easy strategy and provided a brief demonstration in a recent webinar:

High Availability for SQL in VMware without Raw Device Mapping (On Demand Recording)

You may also be interested in viewing the following Clustering 101 webinar hosted by Microsoft Cluster MVP, Dave Bermingham:

Clustering 101 Webinar: VMware Guest Based High Availability Clusters – Ways to Protect SQL and Maintain Flexibility
(On Demand Recording)

Press Release: SIOS Technical Evangelist to Discuss Protecting Business Critical Applications in Cloud Environments at Cloud Expo

June 4, 2015 by sios2017

SAN MATEO, CA – June 4, 2015 – SIOS Technology Corp. (www.us.sios.com), maker of SAN and #SANLess clustering software products, today announced that SIOS Senior Technical Evangelist and Microsoft Clustering MVP, David Bermingham will present a session about protecting business critical applications in cloud environments at Cloud Expo taking place next week in New York, NY.

Titled, “Protecting mission critical applications in cloud environments,” David’s session is scheduled for Thursday, June 11 at 4:50 pm at the Javits Center, New York, NY. For more information about the Cloud Expo or to register, visit here.

Gartner predicts that the bulk of new IT spending by 2016 will be for cloud platforms and applications and that nearly half of large enterprises will have cloud deployments by the end of 2017. The benefits of the cloud may be clear for applications that can tolerate brief periods of downtime, but for critical applications like SQL Server, Oracle and SAP, companies need a strategy for HA and DR protection. By adding SANLess clustering software as an ingredient to Windows Server Failover Clustering, companies can provide HA and DR protection in a cloud where traditional shared-storage clusters may be impractical or impossible. Attendees at David’s session will learn the truths and myths of HA and DR in cloud deployments that can dramatically reduce data center costs and risks.

About the Speaker

David Bermingham is recognized as a high availability expert and has been honored by his peers by being elected to be a Microsoft MVP in Clustering since 2010. David’s work as Senior Technical Evangelist at SIOS Technology Corp. has him focused on helping enterprise companies provide high availability and disaster recovery solutions for their business critical applications.

About SIOS Technology Corp.

SIOS Technology Corp. makes SAN and #SANLess software solutions that make clusters easy to use and easy to own. An essential part of any cluster solution, SIOS SAN and #SANLess software provides the flexibility to build Clusters Your Way™ to protect your choice of Windows or Linux environment in any configuration (or combination) of physical, virtual and cloud (public, private, and hybrid) without sacrificing performance or availability. The unique SIOS #SANLess clustering solution allows you to configure clusters with local storage, eliminating both the cost and the single-point-of-failure risk of traditional shared (SAN) storage.

Founded in 1999, SIOS Technology Corp. (www.us.sios.com) is headquartered in San Mateo, California, and has offices throughout the United States, United Kingdom and Japan.

# # #

SIOS, SIOS Technology, SIOS DataKeeper, SIOS Protection Suite, Clusters Your Way, and associated logos are registered trademarks or trademarks of SIOS Technology Corp. and/or its affiliates in the United States and/or other countries. All other trademarks are the property of their respective owners.

Contact:

Beth Winkowski
Winkowski Public Relations, LLC for SIOS
Phone: 978-649-7189
Email: bethwinkowski@US.SIOS.com

DABCC: SIOS DataKeeper SANLess Clustering Software is Now Microsoft Azure Certified and Available in the Azure Marketplace

April 2, 2015 by Margaret Hoagland

SIOS Technology Corp. (www.us.sios.com), maker of SAN and #SANLess clustering software products, today announced that its SIOS DataKeeper Cluster Edition software is Microsoft Azure certified and now available in the Azure Marketplace. The new SIOS offering is the only Azure certified software that enables customers to create a SANLess high availability cluster in Azure using Microsoft Windows Server Failover Clustering.

By adding SIOS DataKeeper software to Windows Server Failover Clustering customers can quickly and easily help protect business-critical Windows environments from downtime and data loss in a cloud or a combination of physical, virtual, or hybrid cloud environment. Now, for the first time, applications depending on SAN-based Windows server failover clusters for protection can be moved to Azure and achieve the more comprehensive high availability protection they need.

“We are pleased that Microsoft has chosen to certify and include SIOS DataKeeper in the Azure Marketplace. By providing fast, convenient access to SIOS DataKeeper software, our Azure Marketplace offering enables customers to deploy their important applications such as SQL, SAP, and Oracle in Azure with the same high availability protection they have in traditional physical server environments,” said Jerry Melnick, COO of SIOS Technology.

“Products like SIOS DataKeeper are pivotal in the cloud transformation,” said Vibhor Kapoor, Director of Product Marketing, Microsoft Azure. “By providing the essential high availability protection for critical applications that enterprises need, SIOS and Azure are enabling customers to take their journey to the cloud with confidence.”

Along with its Azure Marketplace offering, SIOS provides an informative, step-by-step guide to creating a high availability failover cluster to protect SQL Server in Azure IaaS written by Microsoft MVP, David Bermingham. The SIOS DataKeeper offering in the Azure Marketplace is at:

http://azure.microsoft.com/en-us/marketplace/partners/sios-datakeeper/sios-datakeeper-8-bring-your-own-license/

About SIOS Technology Corp.

Founded in 1999, SIOS Technology Corp. (www.us.sios.com) is headquartered in San Mateo, California, and has offices throughout the United States, United Kingdom and Japan.

View this article on DABCC.com