Moving large amounts of data offsite is a difficult thing to do. It is difficult to beat tape drives and an automobile for rapid data replication. Obviously this method has serious limitations. With the rise of Shared Storage, most replication today occurs at the Storage layer. Though application layer replication offers major advantages, it is usually pursued in addition to storage replication.

What is storage replication? Most SANs and many NAS devices offers licensed replication as a feature. GCS' two favorite devices, the HP Lefthand and Dell Equallogic, include these licenses at no cost. By placing a SAN in-office and one at a remote data center, then connecting the sites with sufficient bandwidth, the SANs will replicate data between the two at the block level. This is an efficient method. Unfortunately, the SANs cannot differentiate between legitimate data changes (ie, a saved Word doc) and temporary data changes such as SQL log files. Everything is pushed across the connection. This tends to require large amounts of bandwidth.

The HP Lefthand offers both asynchronous and synchronous replication options. With asynch replication changed data is pushed at scheduled intervals. With synchronous replication the devices attempt near real-time replication. The HP Lefthand only offers synchronous when there is less than 20ms of latency between the sites. The HP Lefthand also offers bandwidth management on the SAN to help restrict the amount of bandwidth consumed on your site-to-site connection.

A readily apparent benefit of SAN replication is virtual machine replication. If my VMs are stored on my SAN, they are replicated to my remote sites. This dramatically reduces recovery time in a variety of outages.

GCS also recommends Microsoft DFS-R for replication of file stores. Simple, reliable and efficient, this technology allows Windows NAS devices to replicate between sites and provide failover in the event of an outage.

The first part of this comparison generated some heated interest in the blogosphere. It earned a response on Dell's Equallogic Blog as well as a couple of well composed comments from both HP and Dell. Dylan Locsin from Dell thought that a few of my points were inaccurate and he even insinuates that I may be misrepresenting myself. I'll respond to his points here:

1) Clustering: His point that my calling Equallogic "clustered" is inaccurate is completely correct. I should have call it "distributed." Equallogic does not offer true clustering across SANs. They don't offer a comparable feature to the Lefthand's Network RAID functionality which allows striping across SANs. Equallogic cannot pool IO resources as it scales.

2) Groups: Dylan interpreted my argument with Equallogic that "Data cannot span more than these two SANs" as a replication argument. It wasn't. With HP Lefthand SANs I can add performance and capacity with each node up to 16 nodes (and even beyond). This avoids silos of performance and storage. I did fail to point out that I was considering the PS4000 series which is the most commonly encountered Equallogic SAN considered device by my clients. The PS6000 series improves this situation.

Dylan wondered why I didn't offer a disclaimer that I sold HP Lefthand. If he scrolls down a bit he'll notice the disclaimer. I also prominently place the Lefthand SANs on my website. GCS does sell Dell servers, desktops and notebooks. We support MD3000i and Equallogic SANs from Dell. I think Equallogic is a fine product. However I firmly believe the HP Lefthand SAN offers the best value for my clients in the SMB market. That said, Dylan, I'm not opposed to also offering Equallogic to my clients that bleed blue. There are many of those, especially in Austin. I don't mean to insinuate that Equallogic is bad product. I've seen clients succeed with both options.

By far our clients and prospects have two SANs in mind, the Dell Equallogic and the HP Lefthand. While both are impressive SANs that are very similar, there are some critical differences.

Clustered Storage vs Cluster-able Storage: Both products offer clustered storage but only Lefthand can tout that out-of-the-box. Each Lefthand includes two chassis by default where-as Equallogic offers dual-controllers and an extremely reliable single chassis configuration. What is the actual difference in reliability? I have not found any real-world tests but if I can get two for the same price as one, I'll go that route. Advantage: Lefthand

Licensing: Both Dell and HP have listened to their clients anger at complicated licensing systems. Both the HP Lefthand and Dell Equallogic offer an all-inclusive licensing method. Unfortunately unless you buy the HP Lefthand Starter SAN Solution, you may need to be the Multi-Site/DR license in the future for real-time failover and failback. Advantage: Equallogic

Density: The HP Lefthand is essentially a ProLiant DL320s server. The Dell Equallogic is custom designed chassis. Because of this difference the Equallogic gets more spindles per U. This is certainly a consideration when you're ordering racks of SANs. It is much less of a concern when order a SAN or two. Advantage: Equallogic

Groups: EqualLogic PS series allows only two SANs in a group. Data cannot span more than these two SANs. With HP's SAN/IQ Network RAID you can span multiple SANs in a variety of configurations. This provides better performance and reliability. Advantage: Lefthand

Site to Site Replication: Out of the box both SANs offer site to site replication. Only the HP Lefthand supports synchronous data replication with automated failover and failback. The Lefthand supports multiple sites in all configurations. Advantage: Lefthand

Obviously a lot of features are excluded as they are quite similar between both products. The reason GCS chose to emphasize the HP Lefthand SAN was a significant price and value advantage. However it is not quite so apparent as when compared to other SAN vendors on the market.

Here is a helpful comparison chart for HP and Dell's iSCSI SAN lines:

Calculating usable disk space on a SAN is dependent on a number of variables. Make sure you're buying the right model with GCS' HP Lefthand SAN Usable Disk Space Calculator. The calculator displays usable disk space across a variety of RAID and Network RAID configurations for the HP Lefthand P4000 SANs.

Joe has been posting a nice buyer’s guide about the features available on various SAN storage products. But it doesn’t really address the question of why move from direct attached storage (DAS) to a SAN. What benefits does a SAN bring to an organization?

To answer the question, we have to look at how storage is purchased and provisioned without SAN based storage.

Say you have an older File Server which currently has 500GB of data but can’t take any more drives.  Performance is fine but you decide you need to upgrade to a new server to add more capacity. You want the new server to have room to grow, so you spec out and order a server with 1TB of disk space. You also have Mail Server. It’s a pretty new server, but you recently merged with another company and the mail store size doubled overnight.  It needs storage and fast, but not a lot as you don’t anticipate the mail store growing so quickly in the future. You have 500GB of storage sitting on the new File Server, but you can’t use any of it to host the mail store.  So you order an external tray with just a couple drives and still end up with more storage than you need.  

Ten months later you look and see that file server data is growing rapidly and the free space is already gone.  You have an external tray attached the mail server, but you can’t use that to attach it to both servers. So you have to purchase a separate tray for the file server.

This example is over simplified, but it highlights three problems of direct attached storage:

·         Poor scalability

·         Poor Utilization

·         Silos of storage

Poor Scalability

It is not uncommon for an entire server to be replaced just to increase capacity. Not only is this expensive, but if the old server was performing fine you are buying additional resources (processing power and RAM) that you don’t really need. Adding external trays allows you to add large chunks of capacity, but what if you only need a bit more space. 

Poor Utilization

Data growth is dynamic which makes calculating your future needs difficult. The lack of flexibility in DAS discussed above and the fact that adding capacity frequently involves downtime or complete server migration leads organization to buy much more storage upfront than they need.  The result is servers with considerable amounts of unused storage.

Silos of storage

Because of the two problems above you end up with servers with spare capacity, but it is unavailable if another server needs it.  You have storage you’ve paid for but can’t use. Organizations respond in two ways, they either accept this inefficiency or start adding multiple services to servers that have space even if it violates best practices.  An example would be adding high usage file shares to your mail server.

How a SAN helps

A properly designed and deployed SAN addresses each of these problems.  SAN based storage is scalable, flexible, and allows storage to be shared between servers.  The end result can be better storage utilization meaning you only buy the storage you need and can easily add more as needed.  SAN based storage is also a critical element that enables organization to effectively utilize advanced technologies like clustering and virtualization.

Hopefully you now understand the benefits of SAN based storage and have decided it’s time to add it to your organization.  As you can tell by the number of features Joe has in his buying guide, there are many more options and decisions to make. Like any new technology deployment, good guidance can mean the difference between a successful deployment and failure. In future posts I’ll break down:

·         What is a SAN? Or more accurately what components make up a SAN?

·         How should a SAN be used and how should it not be used?  There are many ways to deploy a SAN can limit its utility and seem to be more expensive and troublesome than it works.

Most of our clients choose between an Entry Level or Mid-Level SAN, as described in Part 1 of this Buyer's Guide. In this post I'll identify the features that differentiate those two classes of SANs.

Clustering: Clustered SANs operate like clustered servers. If one fails the other takes over immediately. This is only available in the Mid-Level products such as HP Lefthand, Dell Equallogic, etc. Only HP's Lefthand offers true clustering out of the box. The minimum order for a Lefthand SAN is two completely separate units.

Thin Provisioning: Mid-level SANs allow  you to oversubscribe storage by allocating storage to a volume without reserving that storage. If you create a 100GB volume but only use 40GB, the remaining 60GB is free to be allocated to another volume. This feature is essential in maximizing the storage efficiency of a SAN.

Offsite Replication: Replication between SANs is the foundation for an excellent DR solution. Replicate all data and VMs to another site. Many of the mid-level SANs offer this solution but in some it is a licensed add-on. HP's Lefthand includes scheduled replication at no additional cost but real time replication and automated failover is an additional license fee.

Snapshots: Snapshotting technology is an on-array backup method that utilizes a relatively small amount of disk space. This is possible to restore entire volumes quickly without relying on external storage.

De-duplification: Long an enterprise only feature, integrated de-duplification is making its way into mid-level SANs. This can dramatically increase the efficiency of storage but can have a significant performance cost.

This brief guide will outline the different SAN classes available to the SMB buyer.

Entry Level: If you're buying a SAN, you need a few basic features. iSCSI support and vendor certification (Microsoft, VMware, Citrix) will meet minimal needs. These will enable your virtual environment to utilize high availability features in any of those vendor's environments. HP's MSA 2012i G2 and Dell's MD3000i both meet these criteria. Expect to spend as much as $15k on these devices. The HP will let you mix and match SAS and SATA drives in a single chassis for best use of your SAN dollars. Neither of these solutions offer thin provisioning or clustered storage. What's that mean? Less efficient per GB and much greater risk of failure. If you're concerned about putting all your VMs in one basket, and you should be, then look to the Mid Level, below.

Mid Level: This is what you want, if you can afford it. Two major features enter play here: thin provisioning and clustered storage. I'll touch on both of these now with more to come soon. Thin provisioning allows for oversubscription of storage. Don't worry about it, just do it. Clustered storage is like clustered servers. Two, or more, boxes configured for failover. The HP Lefthand provides the lowest entry cost to true clustered storage. Dell's Equallogic, Compellent, NetApp, Xiotech and others each offer some unique features. Expect to spend at least $30k on this device.

Enterprise: Forget about it. You can't afford it and wouldn't fit in your server closet if you could. Vendors such as HP, EMC, IBM, NetApp and others live here.

Virtual Storage Appliance: For those organizations that may already have a large investment in internal storage in servers or direct attached storage, a VSA may be the best bet. This software solution aggregates storage across your servers into an iSCSI SAN with similiar feature benefits to a full system. You will be able to support High Availabilty and VMotion/Live Migration with this solution. Obviously since you are only buying the software the entry cost is much lower than a hardware solution. HP's Lefthand offers a VSA for VMWare (Xen and Hyper-V are coming). StorMagic has an interesting option that currently supports only VMWare as well, but Hyper-V support is coming.

A not-too-brief market overview should whet your appetite. Look for more info on the features and key differences between vendors to come soon.

GCS' Early Happy Hour was filled to capacity by IT Executives from all over Central Texas. For many it was their first look at Windows 7. Many attendees agreed that the upgrade to Windows 7 is unavoidable. Following the demo, some attendees even looked forward to it! Our discussion highlighted the improved UI, Branch Caching, Windows XP Mode and AppLocker.

In addition to Windows 7 the attendees got a look at Windows Server 2008 R2. We spent quite a bit of time talking about Hyper-V, System Center Virtual Machine Manager R2 and the new Live Migration features. Marquis covered Clustered Shared Volumes in depth, as they pertain to Live Migration. We also covered the new Active Directory Recycle Bin and Branch Caching.

We wrapped up the event with a look at VMWare's VSphere 4. The new Fault Tolerance features garnered the most interest. VSphere's Fault Tolerance allows for failover between hosts without downtime. They have set the standard here. Unfortunately most of the new features in VSphere 4 are not included in the Essentials and Essentials Plus package which is the only version that is price competitive to Hyper-V.

We'll be hosting our next even soon, focused on Cloud Computing in the SMB environment.

We're finally seeing the ProLiant G5s and virtualization-enabled PowerEdges become widely available in the used server market. Many clients are asking for our recommendations. In a virtualized environment with VMware's High Availability or Microsoft's Failover Clustering, is used hardware an acceptable option?

First let me say that I've long been opposed to used hardware in traditional environments. The hardware represents a small portion of the overall cost of the implementation. The installation and configuration, whether performed in-house or by a consultant, is wasted when the hardware has to replaced. I would rather see that service cost spread across four of five years of use. Why save a few thousand dollars to sacrifice a lot of ROI? Cash is the only valid reason. The difference between new and used gear is rarely enough to determine the fate of a project.

Now we have a highly available, virtualized system. We have architected enough capacity to easily run in the event of a single server failure. Are we more comfortable pushing the typical refresh cycles of servers? YES! If we're only refreshing from a fear of hardware failure, then used equipment should be an option considered. In two recent projects we've been able to go from 20ish servers to two servers without buying a single new server! We're reusing equipment from the organization in these cases, but that compares well to procuring used hardware.

Make sure when ordering that your hardware is identical to take advantage of the high availability features. SANs are still new enough to have limited availability on the used market. If you can knock $20k or $30k out of the upfront cost by using used servers, why not?

When should I recommend Cloud solutions to my clients? I don't know. Today I'm going to start figuring it out. I'm going to compare an on-premise build with a cloud based solution for a hypothetical 50 employee organization. Allow me to skip a lot of details and say it will provide roughly equivalent features and security. Anything required in both solutions was a wash and therefore ignored. What you're left with is mostly a lot hardware (servers, SANs, firewalls, switches for iSCSI, etc), deployment services and hardware-level support.

NOTE: All pricing is retail and rounded. Individual proposals may vary. A greenfield is assumed - no data migration. Everything that was common to both solutions was excluded so this may represent a small portion of the overall project. 

Cloud Offering:

In the cloud we'll procure 20Ghz of processor capacity, 50GB RAM, 3 TBs storage with 10 Mbps of bandwidth to host 15-18 Virtual Machines. Onsite backup for 1.5 TBs. This will run about $10,000 per month.

On-Premise Offering:

On-premise will provide provide about 60Ghz (over 24 cores), 96GB RAM, 3TB direct attached storage for backup, 3TB iSCSI SAN. We'll plan on hosting 25-30 VMs on this platform. You'll get this for about $160,000 including 200 hours for installation and configuration. See my build here. Note we dropped 25% of capacity for high-availability.

To even the playing field we have to factor in datacenter costs for the On-Premise Offering. I see a rack, 10Mbps of bandwidth, and 40A of power. Say $3000 per month?

Conclusion:

Let's compare 3 years of costs. In the cloud you're out $360,000. At home, including the data center costs, you're looking at $268,000. The $92,000 delta has to cover the hardware support and maintenance for 3 years. There is some difference in capacity and reliability. I hope it helps your evaluation to say that the cloud offering, in this case, is 35% more expensive.

Click image for single page PDF

A recent project has forced me to analyze two cloud computing providers - Terremark and Rackspace. In this post I'll discuss my analysis of the two services and use a recently completed Private Cloud project to provide cost comparison.

Terremark's Enterprise Cloud service fit the needs of my client best. This is a fully virtualized environment that completely divorces the client from hardware concerns. The Enterprise Cloud enables rapid deployment of Virtual Machines. All management services from the OS up and managed by the client.  It consists of HP ProLiant servers with a 3Par SAN. Redundant firewalls and load balancers are included in every package. All equipment is shared. Virtualization is performed using VMWare ESX 3.5. Server management occurs through a web application and includes many tasks that you would find in VMWare's management tools. Terremark offers packages at fixed Ghz and GB or RAM (entry is 5Ghz and 10GB RAM). You then add storage, backup and bandwidth. There is no incremental charge per VM, only for the resources it consumes.

Rackspace's Platform Hosting takes a different approach. They supply a mix of dedicated and shared resources to create a similar environment. Firewalls, load balancers and servers are dedicated. SAN resources are shared. Rackspace allows access to the VMware infrastructure tools so all functionality is exposed. Rackspace's price plans vary based on hardware redundancy and resources required.

Some interesting points:

• Terremark offers technical support 12 hours per day. Rackspace's support is 24/7/365.
• Terremark is hardened to withstand a CAT 5 hurricane. Good thing since they are based in Miami.
• Pricing favored Terremark by 25-30% when comparing environments with similar features.
• Network configuration is limited at Terremark. There is a maximum of 4 VLANs.
• Both solutions offer use of existing licenses or their hosted licenses
• Neither were excited about voice applications due to QoS concerns.
• Rackspace does not offer a backup service in the Platform Hosting option. Backup will require a dedicated server and regular offsite downloads.
• Rackspace included 6 TB of download and unlimited upload in their base plan. They claim it was the equivalent of 20Mbps sustained for the entire month.

Honestly I'm afraid I have to end this blog post by changing the name to a braindump. I am beginning a 30 day demo with Terremark immediately. I will continue to assess the two providers and post the information here. Look for follow up posts soon.

The Xilocore offsite backup solution came recommended from another VAR out of state. When I saw them at the CompTIA Breakaway Summit I made a point to spend some time at the booth. If you're not familar with Xilocore, it serves the same purpose as an offsite SAN replication of VMs and data without needing the offsite SAN, servers, data center, firewall, bandwidth, etc. An onsite appliance is installed that makes a local backup and then replicates the data offsite. In the event of a server failure you can run the VM on the Xilcore box locally. If a more serious or prolonged outage occurs, Xilocore can stand up your VMs at their data center and provide Citrix-based access to those servers. Turnaround times are offered at 24 and 48 hour intervals.

I looked at this solution in comparison to a proposal I was working on that featured offsite SAN replication with offsite server hardware for DR. This was a Hyper-V platform with System Center Management Suite (including DPM). Xilocore had a compelling offer but this client already had collocation, an MPLS WAN and gobs of spare hardware coming after the virtualization project completes. Though not a fit for this client, I'll circle back and investigate more on upcoming opportunities. I'll be sure to post the outcome.

When small and midsize businesses find the need to invest in a storage area network solution they are faced with lots of options.  The modular, clustered, iSCSI SAN products offered by EqualLogic (Dell) and LeftHand (HP) have become highly attractive solutions for organizations moving into virtualization that need robust solutions with integrated replication.  But, these are complicated solutions and gathering information to compare these offerings can be a challenge.

The Info Tech research group has posted a great PDF (registration required to view) comparing these two product lines and explaining what make clustered SANs different from the more traditional model.  For even more information, check out the blog equallogicversuslefthand.blogspot.com.