The Virtual View

FIBRE CHANNEL IS DEAD

These were the exact words spoken by Vice President and Research Director Drue Reeves at the Burton Group Catalyst Conference in San Diego on Wednesday, with over 2000 IT professionals in attendance. I just about fell off my chair. I couldn’t believe what I heard, and from a major industry analyst. When I first said this back in 1999 when LeftHand was nothing more than a vision, people looked at me like I was crazy.

There are two major factors that are influencing analysts toward this way of thinking. Number one is the rapid adoption of 10 Gigabit Ethernet and the fact that 10 Gig-E will be on the motherboard of your servers within the next 2 years. The second thing is the Fibre Channel Industry’s endorsement of Ethernet with Fibre Channel Over Ethernet or FCoE (see my blog post “The Beginning of a New Era in Storage” November 12, 2007). IT professionals are also starting to realize the significant cost savings of having a single network to manage.

Another conference speaker made the statement, “if you are planning on buying a traditional Fibre Channel SAN today you’re wasting your money.” So what are your choices? According to the analysts it’s iSCSI or FCoE. The only problem is that FCoE won’t be shipping for a few years and they are still trying to figure out how to develop a bunch of hacks to Ethernet to provide congestion management (the IEEE 802.1Qau), enhanced transmission selection (IEEE 802.1Qaz) and priority-based flow control, which are all handled nicely by iSCSI and TCP/IP today. The good news for iSCSI shops is that iSCSI will be able to leverage these enhancements to Ethernet as well.

The question is whether or not you should wait for FCoE or deploy iSCSI now. Let’s face it, FCoE isn’t very compelling. For one thing, iSCSI is IP routable, making it a superior technology to FCoE (not routable – no IP support). Combine this with the fact that you will have to buy all new Cisco gear and HBAs for your servers just to run FCoE, and you’ll understand why I believe that iSCSI will still be the cost leader in 2 years. Intel is promising the first FCoE software initiator, but we all know how that goes. They promised the first iSCSI initiator as well, but Microsoft shipped the first stable iSCSI initiator a few years later and stole the show. I don’t see Microsoft endorsing FCoE anytime soon, and if they do it probably won’t ship for another 2-5 years.

The Fibre Channel guys are running scared and trying to save their high margin business with FCoE. In the mean time the iSCSI market is in hyper growth and moving up market very fast with 10 Gig. With LeftHand’s clustered iSCSI storage, you can build an iSCSI SAN that outperforms Fibre Channel SANs by clustering Gig-E links together, and we have over 3000 customers that chose LeftHand over Fibre Channel to prove it. Imagine when we start clustering 10 Gig links together!

The analysts are right, there’s no future in Fibre Channel. And here’s the best news of all for IT managers – it’s never too late to switch to iSCSI.

SAN based Remote Replication – Changing the Paradigm

Not all SANs are created equal when comparing remote replication capability. It’s amazing to see all the storage vendors marketing their capabilities as if they were technology leaders, when in fact most of their offerings are feature deficient or very expensive to deploy. Let’s set the record straight by taking a look at customer requirements.

I’ve talked with many customers that require offsite replication for DR/business continuity. Here is their consolidated “critical requirements” wish list.

Asynchronous Local and Remote Replication:

1. Scheduled SAN based asynchronous replication over any distance using standard IP networking gear, meaning no Fibre channel to IP bridge equipment.
2. Must work over almost any link bandwidth (T1 being the most common).
3. Technology should minimize the replicated data rate by sending only block level changes.
4. Must have some bandwidth management tools to slice up link bandwidth and share it with other applications that use the remote link.
5. Must provide the capability of failing over servers to the remote site, failing back and incrementally resynchronizing the primary site with the changes.
6. Should provide the tools necessary to replicate application-consistent data sets, making application recovery a simple matter of mounting a set of consistent volumes.

Synchronous Local and Remote Replication:

1. SAN based synchronous replication using standard IP networking gear, meaning no Fibre Channel to IP bridge equipment.
2. Should provide seamless application server failover and failback to the remote site and back with no manual intervention and with incremental data re-synchronization.
3. If a site fails, volumes must automatically remain online at the remaining site.
4. Must work seamlessly with server and application failover software.
5. Must work seamlessly with server virtualization HA products.
6. Capable of utilizing the bandwidth to of fat pipes (parallelism).
7. Must protect against “split brains” (insures data integrity at both sites when the link between sites is down and transactions are still being processed).
8. Capability to bring a site down for maintenance without downtime.
9. Must support applications running on more than one site and replicating to each other.
10. Geographic/site awareness with I/O preferencing based on site/subnet.

When you start going down the list of SAN storage vendors, checking off those that do not meet these basic critical requirements, your options start dropping off rapidly. When you add a requirement to keep costs down, the list thins out even more. Most of the mid-range vendors only support SAN based replication using Fibre Channel, which means expensive Fibre Channel to IP bridge equipment is required on both ends of the pipe along with training and professional services to install, not to mention the outrageous software licensing costs.

There is only one iSCSI vendor out there that offers a fully featured SAN based asynchronous and synchronous replication solution over IP, and that’s LeftHand Networks. Not only does LeftHand steal the show in this regard, but most of the features come standard in the base software offering, which is truly an anomaly, and I challenge any SAN vendor out there to prove me wrong.

If you are looking for a low cost, SAN-based remote replication solution of just about any flavor, over just about any pipe, that leverages your existing Ethernet and IP networks, and works seamlessly with your applications and VMware’s HA capabilities, give LeftHand a call. We’ve got the BC/DR solution for you.

Server Virtualization - The Killer App for iSCSI

Server virtualization implementations began in Test and Development organizations, mostly in large businesses where existing Fibre Channel SANs were already in place. IT managers who are familiar with both technologies began to understand some inherent benefits from using iSCSI as storage for virtualized environments. As the benefits of server virtualization accelerated adoption by smaller organizations, the ease of use and affordability offered by iSCSI motivated end users to implement iSCSI SANs instead of Fibre Channel for storage. 

When asked why, customers had a litany of reasons.

1. iSCSI Simplifies Virtual Machine Mobility for High Availability (HA):  Virtualization increases the need for HA.  With server virtualization, users typically run multiple applications on each physical server, exposing themselves to a potentially significant impact if a server fails since every single application (all the VMs) running on that server will go down.  To solve this problem, virtualization vendors have implemented mobility features that enable VMs to move to other physical servers in the event the server they reside on fails.  Using a FC SAN in this type of environment creates additional complexity.
   1. Every VM must be mapped to every FC HBA that could potentially be used as the physical connection to the SAN.
   2. Every FC HBA that a VM may use must have access to that VMs’ storage.

The multiple layers of relationships (VM to HBA to storage) creates complexity and make the FC SAN difficult to manage.

iSCSI avoids this complexity because it uses an IQN (iSCSI qualified name) on each virtual machine that can be mapped directly to its storage.  There are no intermediate hardware relationships to complicate things.  With iSCSI, VMs are mapped directly to their storage and that relationship remains even if the VM moves to a different physical server.  iSCSI also eliminates the FC requirement of ensuring that all VMs are related to any HBAs that might have to be used.

This brings us to a second issue. Security.

2. iSCSI Simplifies Security for Virtualized Environments:  The hardware-centric nature of Fibre Channel (FC) creates a number of problems when implementing virtual machines.  In FC environments WWNs (World Wide Names) are used to uniquely identify equipment in the SAN.  The WWN is an identifier tied to specific hardware such as a server HBA or a storage array.  In virtualized environments, this dependency on physical hardware intensifies the complexity of managing the environment and exposes new security risks.  iSCSI provides a number of advantages in virtualized environments.

If you map VMs to a FC HBA, and then map that HBA to the storage, every single VM on that server has access to every other VM’s storage.  Users can leverage the security features in the hypervisor or new emerging FC security features to sort this out, but this creates additional complexity and management.

iSCSI is not exposed to this because each VM is mapped to its own storage and there is no need to have to use the hypervisor or some new FC switch to manage security between VMs.  Standard Ethernet security protocols like CHAP authentication are used to effortlessly ensure a secure connection.  Likewise, since iSCSI is standard IP (Internet Protocol) traffic any/all common IP security mechanisms work.

3. iSCSI Delivers Performance Without Configuration Headaches:  Virtualization increases server utilization.  By running more applications on a single physical server, end users can achieve much higher utilization rates for servers.  However, most FC SANs are configured assuming a load from one application per server.  By increasing the utilization of the server with multiple virtual machines you increase the amount of performance the server requires from the SAN.  If zones and LUNs are not properly set up to accommodate this increase in load, VMs can experience disk contention resulting in inadequate performance.

iSCSI avoids disk contention by providing each VM with the ability to connect directly to its storage.  Users aren’t constrained by the storage resources to which the server is mapped, and have the flexibility to map each VM independently so disk contention issues are avoided.

These are just a few of the advantages that end users are discovering about iSCSI vs FC in virtualized environments.  Emerging iSCSI storage vendors like LeftHand Networks take these advantages even further.

LeftHand Network’s Performance Advantage for Server Virtualization:  As higher utilization rates of servers are achieved SANs are required to provide higher performance.  Of course users can purchase a new controller and rip and replace their existing one, but even then users may have to reconfigure their SAN so that zones and LUNs can accommodate the increased load resulting from the multitude of virtual machines.

Performance issues in a virtualized environment can be avoided with a LeftHand SAN.  LeftHand delivers a clustered storage system, whereby each unit in the cluster provides network connections, processing power, controller and cache. The LeftHand SAN automatically balances the load from all VMs evenly across each unit in the cluster.  By distributing the load evenly, controller bottlenecks are avoided.  In addition, each volume on the SAN leverages every single disk drive, network connection, and processor in the SAN ensuring consistent performance of every volume and avoiding disk contention issues.

Beyond performance, LeftHand can also simplify manageability of highly available environments.

Seamless VM and Storage HA, No Manual Intervention for Failover and Failback:  Lots of vendors talk about enabling virtual machine HA, but the fact of the matter is if a storage system does not provide HA, the environment is not highly available.  If the storage goes down, the VMs don’t have access to the data.  To implement highly available storage, traditional vendors use synchronous replication where they keep two volumes synchronized so that if one volume goes down, the other is an exact replica.  The issue with this approach is that if VMs come back up in the secondary site, they have to be remapped to the secondary volume.  This same issue occurs when users failback to the primary site.  This is a manual process and at best it is done by scripting.

A LeftHand SAN avoids these complex manual tasks.  By managing two copies of the data (one at each location) within a single volume on the SAN, virtual machines don’t ever have to be connected to the secondary volume or reconnected to the primary.  These tasks are eliminated altogether as the virtual machines remain connected to the same volume regardless of physical location.  Now the entire environment, including applications, virtual machines and storage, is highly available with automated failover and failback capabilities.  No user intervention for failover/failback is ever required.

With all of the advantages of iSCSI over FC in virtualized environments, plus new emerging vendors like LeftHand Networks taking performance and availability to the next level, iSCSI storage is proving to be the defacto standard for server virtualization environments. 

What Does Data Protection Mean to You?

Reliability is one of the most critical factors for customers when choosing a SAN. The reasoning is simple: system reliability translates directly to data loss and downtime.  The most vital component in a SAN is the disk drive, where the data is physically stored. Since data loss is unacceptable, protection against disk drive failure is a must. LeftHand’s Storage systems deliver advanced data protection levels to safeguard the SAN from multiple disk failures in the same array, complete array failures, and site failures without losing data or availability.

If we take a closer look at how the reliability model, specifically for disk drives, has changed over the years, I believe you will start to understand why legacy data protection technology isn’t sufficient anymore.

Most of you are probably familiar with the term MTTF (Mean Time To Failure). Storage system availability and reliability are calculated based on the MTTF of all the components that make up the storage system along with their level of redundancy. In spite of its proven inaccuracy as a predictor of reliability, MTTF is the basis for most vendors’ reliability calculations.

Bianca Schroeder and Garth Gibson at Carnegie MellonUniversity presented an analysis of field-gathered disk replacement data from a number of production systems totaling about 100,000 disks. Data from their analysis revealed that replacement rates in all years, except for year 1, are higher than the disk drive datasheet MTTF specification. In years 4 and 5 (which are still within the nominal lifetime of these disks), the actual replacement rates were 7–10 times higher than the failure rates expected based on datasheet MTTF.

This simply means disk drives will fail more than the disk drive and storage system manufacturers say they do.

So now let’s talk about Bit Error Rate and how that influences reliability. Bit Error Rate, or BER, is the most critical factor of all. BER simply means that while reading your data from the disk drive you will get an average of one non-recoverable error in so many bits read, as specified by the manufacturer. This ratio has nothing to do with the MTTF.

The data storage industry has followed Moore’s law for semiconductor memory:  capacity doubles every 12 to 18 months. This has held true for the past three decades or more in hard disk storage. Disk drive capacities have gone from 5 MB to 1TB in just 25 years - a 200,000-fold increase. Disk drive capacities are up 1000-X from 1 GB to 1TB in just the last 10 years. Alarmingly, as drive capacities have increased, BERs have remained relatively constant. So a drive with a 1000-times increase in capacity will experience a non-recoverable read error event 1000 times more frequent when reading the entire disk drive, which is a common operation when rebuilding a hot spare or failed drive replacement in a RAID set.

Rebuilding the data on a replacement drive with most RAID algorithms requires that all the other data on the other drives be pristine and error free. If there is a single error in a single sector, then the data for the corresponding sector on the replacement drive cannot be reconstructed, and therefore the RAID rebuild fails and data is lost. The frequency of this disastrous occurrence is derived from the BER. Simple calculations will show that the chance of data loss due to BER is much greater than all other reasons combined.

The probability that data will be lost in the course of a rebuild operation can be estimated on the basis of the total capacity of the array combined with the probability of a bit error occurring on an individual drive. The bit error probabilities provided by drive manufacturers typically range from 1:10^14 for SATA drives to 1:10^16 for Enterprise Class SAS drives. The diagram below shows that an increase in a drive BER of one order of magnitude has serious consequences for large capacity arrays.

This data is very alarming when considering the proliferation of SATA drives in the enterprise. Customers that are aware of this exposure may choose to implement RAID 1 or RAID 10 protection schemes to address the shortcomings of SATA drives. What we do know about older SATA drives is that they have low MTTFs and the Bit Error Rate is 1:10^14. That's approximately 1 bit error per 11.6TB read. Compare this to SAS drives with a BER as low as 1:10^16 which is 1 bit error per 1,164TB read.

Looking at a real life example, a 14 drive array with 750GB SATA drives configured with two 7 drive RAID 5 sets has a 38.7% probability of experiencing a non-recoverable read error during a RAID re-build. This means there is a 38.7% probability of losing all your data when a drive fails, even though the array is protected by RAID 5! With 1TB drives the probability is 51.5%. Even in RAID 10, where drives are typically configured in mirrored pairs, the probability of a read error is still 8.6%. That’s pretty frightening.

Another alarming fact is that some storage vendors allow RAID groups to span multiple disk shelves, where 10s of drives can reside in a single RAID 5 set. Take a 12 drive RAID 5 set of 1TB drives; it has nearly a 100% probability of data loss during a RAID reconstruct!

Customers should be asking the hard questions of any storage vendor selling SATA drives without some form of double-error protecting RAID. Even with 400GB Enterprise Class Fibre Channel drives with a BER of 10^15, you still lose data in about 2% of 7 drive RAID set reconstructs. Even a 1% probability of data loss is unacceptable to most customers, especially when considering that dreaded backup window.

How LeftHand Networks is Changing the Data Protection Paradigm

LeftHand Networks offers multiple options for data protection:

1. RAID 5 and 10: LeftHand supports widely used RAID levels. When combined with Network RAID a customer can protect the SAN from multiple disk and array failures without sacrificing performance.

2. RAID 6: LeftHand supports hardware RAID 6 in the array, which protects against double disk faults and BER events during rebuild.

3. Background Scrubbing: LeftHand uses non-intrusive background disk scrubbing that corrects defective drive disk sectors and BER events before they cause a drive failure.

4. Network RAID: Stripes and replicates data across the SAN with local and remote options. Network RAID protects data from double disk faults in a RAID set, complete array/node failures, and even site failures in a Campus or Multi-site SAN configuration. LeftHand is the only storage vendor offering this advanced level of data protection.

Since SATA drives have historically had much higher BERs than Fibre Channel and SAS drives, many vendors recommend RAID-6 for SATA drives if they’re used for important data. LeftHand not only provides RAID 6, but also provides even more advanced data protection with Network RAID. These features can protect your data from a multitude of failure possibilities.

How Green is your SAN?

Being green is all the buzz these days. You have HDS growing foliage out of their storage systems on their home page, SNIA stirring up Green Standards, and every other vendor out there clamoring about how green they are, even if they’re not. Howard Goldstein has a great spin on all the hype in his green storage networking video clip.

Green storage can mean many different things and be spun just about every way you can imagine, so here is my spin, which I like to think is a little more factual. I see the most important factor being storage utilization efficiency. Software features like thin provisioning greatly improve storage utilization and minimize unused spinning disks. LeftHand’s Thin Provisioning software uses allocate-on-write technology, which means “reservationless storage” – no need to provision a bunch of storage to a volume that may take years to fill up.

Another obvious focus area is power consumption, or how power hungry your storage processors and disk shelves are. Thin Provisioning saves power by eliminating the allocated-but-unused spinning disks. Need proof of its value? Look at our competitors. Thin Provisioning is included in our base software offering and we don’t charge extra for it. Now that other vendors have finally caught up (HDS for example), they are making a huge deal out of it, and charging a considerable sum for it.

Another example of power saving technology is LeftHand’s Virtual SAN Appliance (VSA). This software can take stranded storage that’s sitting in your servers, unused and still consuming power, into a shared SAN.

Taking a look at storage processors, AMD and Intel are clearly leading the industry when it comes to developing technology that makes x86 processors more power efficient. According to Intel, their dual core architecture provides an 80% performance increase over existing Xeon processors while reducing power consumption by 35%. A few words from Intel’s CEO Paul Otellini describe it best:

"Today, for every dollar you spend on server hardware, you're spending 50 cents to cool and power that machine. By 2010, it goes up to 70 cents per dollar, so focusing on energy efficiency is becoming job one."

More processor cores means more processing or Watts per minute per job. This is driving server and storage consolidation, in turn significantly reducing power and space requirements (see table below).

In fact, all of LeftHand’s disk arrays now run on Intel multi-core processors. Our real industry advantage comes from the fact that LeftHand’s SAN/iQ is hardware agonistic, so we can bring advanced storage virtualization and management capabilities to the greenest storage platforms available.

LeftHand’s Storage Platforms also use the latest power-saving disk drive technology: reliable, inexpensive SAS drives, which consume less power and will, I believe, eventually replace all shared bus drive technology, including Parallel SCSI and Fibre Channel Arbitrated Loop. Typical power consumption for a Fibre Channel drive is 18.8 Watts, compared with 17.4 Watts for SAS drives based on disk drive specifications from the manufacturer. SAS drives also perform better – no shared SCSI buses, no arbitrated loop I/O contention, no more LIP storms or FC drive chatter – all dedicated, high speed point-to-point serial interconnects.

Last week we were competing with a Fibre Channel drive vendor who argued that “SAS drive technology limits scalability.” He clearly hadn’t done his homework. SAS technology allows you to connect up to 16,384 drives in a single system, and LeftHand’s clustering software is capable of connecting as many systems together as you need into a single pool - so much for that argument.Customers are smart, and they’re starting to figure out the truth.  And let’s not forget about iSCSI’s no-power-required software initiator instead of that that 6.5W HBA that needs to be installed in all your servers in order to connect to a Fibre Channel SAN.

So how can you find a solution that’s really green? Look for a storage solution that takes advantage of power savings from leading processor technology, provides low power consumption disk drive technology, and provides software that allows you to manage your storage efficiently and grow it as needed without disruption or rip-and-replace controller head upgrades.  That’s a green SAN.

The Beginning of a New Era in Storage

ISCSI finally got its day in the sun last week. Dell’s acquisition of EqualLogic confirming what we all know -- people are drowning in their data. What does an outmoded technology do when the industry giants (like Dell) start casting their vote?

Fibre Channel is to iSCSI what Beta is to BlueRay. The Fibre Channel guys are running scared. Customers see the tremendous savings offered by iSCSI, not only in acquisition, training, and operational costs, but savings from advanced virtualization technologies like thin provisioning, resource aggregation and high availability; It’s about doing more with less and solutions that allow storage to be managed independently of the hardware in the same manner as the new matriarch of storage--VMware.

Fibre Channel vendors have seen the writing on the wall and are now trying to save their ship by hopping on the Ethernet bandwagon. The technology is called FCoE (Fibre Channel over Ethernet.) Catchy name, huh?  Which presumably will allow application severs to connect to Fibre Channel SANs over standard Ethernet, helping reduce the need for costly HBAs and switches. The hyped advantage is the elimination of TCP/IP overhead.

Fibre Channel sheep (blind followers) have been positioning iSCSI as unviable since the day iSCSI it was conceived because of TCP/IP overhead and its impact on performance. Bahhh. Today’s server processors can easily handle the small incremental overhead of iSCSI TCP/IP and it’s only getting better. Intel’s new I/OAT technology offloads the TCP/IP stack onto one of the cores of a multicore CPU, allowing the applications to run unimpeded on the remaining cores. Not only do software initiators work perfectly running on today’s dual and quad-core processors, it will only get better with octal-cores. What the Fibre Channel guys won’t tell you is the important features you lose by not having TCP/IP: congestion control and guaranteed delivery.

Is iSCSI the be-all and end-all? Where does LeftHand see the market going? This is material for many future blog posts, but I’ll give you a few hints. We see the use of 10 Gig Ethernet and beyond allowing customers to create different “channels” of communications. One could be for the interprocess communications between blades on a blade server, another channel for Remote Direct Memory Access (RDMA) or Infiniband for high speed, low latency communications, and another for iSCSI and other IP-oriented connections. Yes and conceivably FCoE too, if it comes to that.

The last remaining question in a Fibre Channel mind is “what about performance?” I’m asked this question from customers just about every day, and my answer is simple. Performance has more to do with the SAN technology and architecture than it has to do with the protocol. Take LeftHand’s scalable SAN architecture for example. LeftHand virtualizes, load balances and aggregates the connections on each iSCSI array. For example, if you have 2 iSCSI arrays, with 2 gigabit ports on each array, you have an aggregate bandwidth to your SAN of 4Gbps, equivalent to 4Gbps Fibre Channel. Once you expand beyond 2 disk shelves, the systems exceed the available bandwidth of a single Fibre Channel link, and scales linear from there.

In our 100TB SAN validation test (www.lefthandnetworks.com/library/third_party_reviews.php) we demonstrated the performance of a 15 node LeftHand SAN replicated across 2 sites. Not only did we exceed the maximum random IOPS of most high-end Fibre Channel SANs on the market today with over 50,000, but we also demonstrated the capability to stream 35,000 videos simultaneously, equivalent to over 1,800 MB/s sustained throughput. Let’s see EMC do that with one of their Clariions! Of course the misperception of iSCSI being slow still persists among those poor customers that were brainwashed “Symmetrix style.” Little do they know that LeftHand’s clustered iSCSI architecture can be scaled to not only outperform Symmetrix, but at the same time also offer higher availability at a much lower cost.

Why is Fibre Channel rushing to new solutions? Survival. Maybe the Fibre channel guys went running for cover when Bell Labs presented results that claimed serial 100-Gbit/s transmission across a 2,000km distance. Clearly with 10 Gigabit Ethernet gaining traction and 100 Gigabit Ethernet on the horizon, FCoE is Fibre Channel’s only hope of survival. As iSCSI continues to take market share, there may not be any share left to take by the time the Fibre Channel guys get done re-inventing TCP/IP and FCoE finally hits the market. By this time the TCP/IP issue will be buried in processor cores.

 

LeftHand SANs

I was asked by a prospective customer the other day, “What does LeftHand sell?  After reading your website, it appears that you’re a storage software company.” LeftHand’s SAN/iQ software is at the core of every LeftHand SAN, providing comprehensive SAN management functionality along with high performance clustering and remote replication. But we sell more than just software: We sell SANs.

Customers come to us for SAN storage solutions that are a combination of software and hardware. LeftHand combines SAN/iQ software with tier-one disk hardware platforms and sells them as fully integrated, reliable, high performance SANs. Our customers use LeftHand SAN storage for Exchange, SQL Server, Oracle, file sharing, and many other applications.

SAN/iQ software has market leading virtualization capabilities that are similar to VMware’s software, but at the storage device level. And now we’re taking virtualization of storage beyond the physical SAN with a version of SAN/iQ that runs in a VMware virtual machine on VI3 servers called the Virtual SAN Appliance (VSA). VSA rescues stranded storage that’s inside your servers and gathers it into a shared pool of storage. In other words, VSA combines the storage inside or directly attached to multiple VI3 servers into a centrally managed, shared SAN that can be provisioned as required to each server. VSA also allows you to take advantage of a wide range of enterprise-class SAN features, such as snapshots, thin provisioning, and replication to remote and branch offices.

There you have it: LeftHand sells complete iSCSI SAN solutions, and our SAN/iQ or SAN/iQ VSA software is integrated into every one of them.

It's RAINing SANs at LeftHand

Last week during a call with a customer prospect I was in the process of explaining LeftHand Networks’ unique IP-SAN storage clustering technology and the benefits it brings to IT environments, and the customer responded “do you mean RAIN (Redundant Array of Independent Nodes)?” He clearly understood what RAIN was, and he was right, it is a very good example of what LeftHand Networks provides

Most IT professionals that deal with storage have a good understanding of RAID (Redundant Array of Independent Drives), a widely used technology that is inherent in most storage solutions today. RAID makes use of multiple physical hard disks in concert to limit the chances that a hardware failure will result in a loss of data. For example, if you have 12 drives in a RAID 6 configuration, there are 2 copies of parity so that up to two drives can fail in a RAID set and the computer can still operate. RAID 6 is important because larger drives take longer to rebuild, increasing the likelihood that a second drive will fail during the rebuild of a first failed drive.

A newer, more advanced way of protecting computer storage is through Redundant Array of Independent Nodes or RAIN. LeftHand refers to this as Network RAID. While traditional RAID relies on specialized drive controllers or operating system device drivers, Network RAID relies on software to organize multiple separate storage servers to provide data reliability. Instead of storing multiple copies of the same data on physically separate hard disks on the same storage system (i.e., disk shelf or cluster node), data is replicated to multiple storage systems. The software that manages the cluster of Network RAID storage systems knows where the multiple copies live. In the event of a storage system failure, the applications continue to operate normally because the Network RAID software maintains additional copies of data as necessary to keep the user-specified level of redundancy and availability.

LeftHand’s SAN/iQ Network RAID takes RAIN to a new level by allowing users to set redundancy levels to accommodate multiple disk failures, array failures and even complete site failures without the SAN data volumes going offline. With LeftHand’s Multi-Site SAN capability, data can be made redundant across 4 sites and accommodate up to 3 sites failing without losing access to data. LeftHand is establishing a new paradigm in highly scalable, redundant SANs that are simple to manage, and more and more customers are finding them easy to rely on.

LeftHand + VMware = Very cool stuff

Not only are LeftHand's fully featured IP-SANs very popular these days, check out this posting below from Luke at VM Squad on LeftHand's new Virtual Storage Appliance http://vmsquad.com/?p=4:

“So at the day job we’re looking at implementing a SAN along with moving server to something virtual (VMware, Virtual Iron or Xensource) . We like the offerings from LeftHand Networks for the SAN. It’s a software based SAN approach will allow us to grow as we need. We’ve got the quotes from them, but the execs are still leary about spending that much money. It’s a typical battle that everyone in IT fights, but we’re finally making progress.

Last weekend LeftHand released their SAN/iQ as a VMware appliance. This is very very awesome. This allows us to test the functionality of it on our network without getting the vendor in here with a SAN on loan that we end up buying because we’ve already started using it on our production network.

We’ve got an AIX server setup with our production data and have it connected via iSCSI to the appliances setup in a two node cluster. Testing so far has been really good over a 100mbit network. Speeds are similar to the SSA drives our production AIX server has. Will definitely update when we have tested it more."

Feedback from VMworld

LeftHand received tremendous feedback on our new VSA product at VMworld last week, and the free downloads of VSA are rampant. An interesting discovery after talking with many customers – only about 25% were aware that shared storage is a requirement for the advanced features of VMware ESX like VMotion. Many of our customers & VARs that we talked with were also very excited to hear that VSA could let them use the “stranded storage” on their ESX servers, and at the same time leverage the benefits of ESX’s advanced features with it.

Another highlight from the show: VMware gave a demonstration of their Continuous Availability for Exchange. If an ESX server fails, VMware’s Continuous Availability delivers instant recovery of a VM on a second ESX server. The demo showed Exchange running in a Windows Server VM and a second VM configured with Continuous Availability to keep it mirrored (in sync) with the first. Microsoft’s LoadSim (simulates an actual Exchange workload) was running against the Exchange Server. When they pulled the power from the first server, the LoadSim application and Exchange continued to run. Now that’s impressive!

This made me think of LeftHand’s HA capabilities. With LeftHand’s Network RAID capability, a user can pull the power from any array in the SAN, or multiple arrays depending on the settings, and the SAN is still fully available. With LeftHand’s Multi-site SAN feature the same SAN spans multiple sites. A complete site – half of your SAN – can be shut down without losing access to your data. Combine this with VMware's Continuous Availability and you have the ultimate HA environment for your applications, servers and storage.