EqualLogic Load Balancing – 3 layer approach
With the new release of PS Firmware Revision 5.1, Dell introduced more advanced data management options. At the core are 3 load balancing layers that ensure high-performance while balancing capacity value. This post describes the 3 layers and how they can be applied.
EqualLogic Load Balancers in PS Series Pools
When you initialize the first array and create a PS series group, a default pool is automatically established. After adding an array to the group, it is referred to as a member of the group. All members are initially placed into the default pool, and administrators subsequently deploy volumes from this pool. It is within a pool that resources such as network bandwidth, disk capacity, and I/O are balanced automatically. Multiple pools can be created to isolate volumes and separate members. This may be done for a variety of reasons, including technical (e.g. placing specific application data on resources such as SSD) or business reasons (e.g. ensuring that legal department data is isolated from the data from other departments.) With more than one pool administrators can initiate moving volumes or members between the pools seamlessly, with no downtime to the applications. Within a pool, Dell’s EqualLogic PS Series is designed to automate the placement of data to maximize the utilization of the resources that the customer has chosen for their SAN.
There are three load balancers that operate within a pool:
- The NLB (Network Load Balancer) manages the assignment of individual iSCSI connections to Ethernet ports on the pool members
- The CLB (Capacity Load Balancer) manages the utilization of the disk capacity in the pool
- The APLB (Automatic Performance Load Balancer) manages the distribution of high I/O data within the pool.
How the Network Load Balancer (NLB) Works
Communications between application servers (iSCSI initiators) and volumes (iSCSI targets) are called connections. An EqualLogic PS series group will present all iSCSI targets through a single virtual address known as the group IP address. This allows administrators to establish connections easily by only having to configure the iSCSI initiator with the group IP address. As the load increases or decreases on the various Ethernet ports, the NLB automatically distributes connections among the active Ethernet ports of the members using a feature of the iSCSI specification called redirection. Redirection defines how the iSCSI target instructs the iSCSI initiator to log out and close the connection to the IP address that it is currently using and immediately log in to another address and establish a new connection. Support for redirection is required for iSCSI initiators by the iSCSI specification. Redirection is utilized by the NLB within an EqualLogic PS Series group to permit the application server to establish iSCSI connections as needed without first needing to be updated manually to know all of the possible IP addresses that the SAN is using. Leveraging redirection, the NLB ensures that all the network interfaces within the SAN are optimally used. The NLB and iSCSI connection redirection are also key functions used by the PS Series architecture to enable volumes and members to migrate seamlessly from one pool to another, and permit members to join or leave the group as required with no interruption in service to the applications.
The NLB should not be confused with Multi-Path I/O (MPIO), which is the load-balancing that occurs on the application host. MPIO uses redundant physical interfaces to deliver high availability to shared storage. Using MPIO, servers can send multiple I/O streams to SAN volumes. Each of these paths uses an iSCSI connection that is managed by the NLB.
In addition to the standard functionality provided by MPIO, Dell provides host tools to enhance the performance of MPIO and to automatically manage the connections for Windows (including Hyper-V), VMware and Linux environments.
How the Capacity Load Balancer (CLB) Works
The CLB ensures that as volumes are created and deleted, and as members are added to and removed from a pool, the relative percent of capacity in use is maintained at a consistent level among the members in that pool. Keeping the members in the pool filled to the same percentage of their disk capacity helps to ensure that all of the resources in the pool are used equally, and helps avoid overloading one member compared to another. It can also help ensure that members have the necessary free space available to perform other tasks such as replication and internal maintenance properly.
When the CLB assigns a portion of a volume to an array, it is called a slice. The CLB will attempt to satisfy the capacity needs of each volume with a distribution policy that typically limits the number of slices per volume to three. More than three slices will only be created when the capacity requirements of a volume cannot be satisfied with three slices.
Most administrators choose the default “Automatic” RAID preference setting for the majority of their volumes. The CLB will normally choose the members to use without regard to RAID level unless the administrator selects a specific RAID preference type for the volume (for example, RAID6).
If an administrator chooses a specific RAID type and it is available in the pool, the CLB attempts to honor the preference request and place the volume on members with the requested RAID type. As long as all of the volumes that are requesting a particular RAID type can be accommodated on members of that RAID type they will be, even if this results in the members of the pool with the requested RAID type having higher capacity utilization than other members of the pool. If the request cannot be honored because there is insufficient capacity available (or no members) at the requested RAID type, volumes will be placed on other resources in the pool as if the RAID preference had been set to “Automatic”. Setting RAID preference for a volume in an existing environment may cause other volumes with their RAID preference set to “Automatic” to have their slices moved to members other than the ones that they resided on prior to the change.
When the CLB needs to re-adjust the distribution of the data in the pool, it creates a rebalance plan (RBP). Some examples of when a RBP is created are in response to either a change in the resources available in the pool (e.g. adding or removing a member), or a change in the way that the current resources are used (e.g. adding a volume, changing a snapshot or replica reserve, modifying delegated space for the replicas from another PS Series group, or due to the growth of a thin provisioned resource). An RBP is influenced by any RAID preference settings for the volumes in the pool and will, when possible, honor RAID preference settings for volumes as discussed above. As resource usage is optimized, an RBP may temporarily create a capacity imbalance, but after the RBP is executed the imbalance will be rectified.
Similar to an RBP, the CLB can also create free-space-trouble plans (FSTP). An FSTP is created when the CLB determines that a pool member has reached a critical point (10% free space) and there is free space available on other members in the pool. An FSTP will cancel other RBPs. Once the low space issue that prompted the FSTP has been resolved, the CLB will create new RBPs if they are required.
All data movement, regardless of whether caused by an RBP or FSTP, is handled in a transactional manner, i.e., data is only removed from the source of the transfer and internal metadata that tracks the location of the data is updated only after its receipt is confirmed by the target of the transfer.
How the Automatic Performance Load Balancer (APLB) Works
The APLB feature is designed to help alleviate the difficulties inherent in manually balancing the utilization of SAN performance resources. Operating on the resources in a pool, The APLB is capable of adjusting to dynamic workloads in real time and at a sub-volume level. It will provide both sub-volume based tiering when presented with heterogeneous or tiered resources to work with, as well as hot spot elimination when presented with homogeneous resources in the pool.
The APLB optimizes resources in an EqualLogic PS Series pool based on how the applications are actually using the SAN resources. Once the slices have been assigned to members in the PS Series pool by the CLB and I/O begins, certain patterns of access may develop.3 Due to the random nature of I/O these access patterns are often unbalanced, which while perfectly normal, may place more demand on certain EqualLogic PS Series members than on others. Often, the imbalance will occur within the same volume, with portions of the volume exhibiting high I/O, while other portions of the volume exhibit low I/O. This imbalance can be detected and corrected by the APLB.
In an EqualLogic PS Series pool, all other EqualLogic PS Series products can adjust to this potential imbalance in latency: in the event that a workload causes a particular PS Series member to exhibit relatively high latencies compared to other members of the same pool, the APLB will be able to detect and correct this imbalance and by exchanging high I/O data from the PS Series member with high latency for low I/O data from a peer with low latency. This rebalancing results in better resource utilization and an overall improvement in the performance of all of the applications using the resource of the EqualLogic pool.
The APLB is surprisingly simple in its concept and execution, leveraging various aspects of the EqualLogic architecture to automatically balance the performance delivered to applications by the PS Series SAN. For example, the rebalance plans that the CLB uses to re-adjust the placement of data, are leveraged by the APLB as well. Instead of the typical one-way movement that the CLB usually performs, movement of data in the RBPs that the APLB creates is typically a two-way exchange between PS Series members to ensure that after a performance rebalance operation the capacity balance is still maintained.
As with all EqualLogic management tasks, the APLB runs with a lower priority than the processing of application I/O. Every few minutes, the APLB analyzes the range of latencies of member arrays in an EqualLogic pool, and determines if any of the members have a significantly higher latency (20 ms or greater) than the latency of the lowest latency members(s) in the pool. If it does, the APLB will attempt to identify workloads that could be rebalanced by moving high I/O data to less heavily loaded members (i.e. those with lower latency). If any are identified, then a RBP will be created to exchange a portion of the high I/O data from the member with high latency with an equivalent amount of low I/O data with one of its peers supporting the workload that has been selected for rebalancing. The peer member that is chosen for the data exchange will be one of the other members in the pool already supporting a slice of the volume that has been selected to be rebalanced.
When the APLB is presented with more than one option for rebalancing, i.e., the volume selected for rebalancing has slices on two other members in a larger pool, and the latency of both options is similar, then the APLB will use a second criteria to make the determination. This second criteria is the relative “busyness” of the arrays, which is a composite score of factors such as RAID type, disk speed, number of disks, as well as EqualLogic controller type and the current I/O load. The array with the lower relative busyness will become the array chosen for data exchange.
The APLB works well in a variety of environments. For example, in EqualLogic pools with members displaying similar performance characteristics, the net effect is to eliminate “hot spots” in the pool. In pools with members displaying dissimilar performance characteristics (for example arrays with different drive types), the net result is tiering of the data such that the bulk of the active data will be serviced by the array(s) with the most I/O capability.
The data that is used to determine what portion of the workload is high I/O is based on recent activity, (on the order of minutes) so the APLB is able to adapt to a change in an application I/O pattern quickly. The APLB is also dynamic, constantly evaluating the environment and making small adjustments as required. Once an application has reduced its demand for resources the APLB does not continue to “optimize” the formerly active data.
The advantages of the APLB approach are fourfold:
- Seamless support of 24/7 business activities: By adjusting incrementally there are no large batch movements of data. Instead, the APLB spreads the overhead of rebalancing into small operations through the day instead of in one large activity.
- Ability to adjust to cyclical or one-time workload changes: By evaluating a relatively recent window of activity, the APLB detects the temporary nature of certain increases in I/O load (such as end of month financial activity), and they don’t continue to influence the balancing of data after they are no longer relevant.
- Reduction of “worst case scenario” purchasing: By working continually, the APLB can detect and act on cyclical business processes, such as increased end of month activity by the finance group enabling the resources of the SAN to be leveraged in near-real-time. This may enable IT management to purchase fewer resources since each application can better leverage the storage when it needs it most.
- Future-proofed load-balancing: Finally, by using latency as the primary criteria, the APLB does not need to explicitly evaluate any other details of the storage, such as disk type (e.g. SAS vs. SATA), spindle speed, number of disks, or EqualLogic controller type. This makes the APLB a very simple and robust mechanism that does not need to be re-trained when new hardware configurations are introduced to the EqualLogic product line. This also ensures that when unplanned events occur that may influence the ability of certain arrays to serve their workload (e.g., RAID rebuild or bad NIC) that the system automatically compensates.
Tiering with the APLB
When provided with tiered resources in a pool, for example arrays with different spindle speeds or set to different RAID types, the APLB is able to use them to tier the workload. This is not limited to any particular RAID type, interface I/O type, spindle speed, number of disks, or EqualLogic controller generation since the use of latency as the primary factor when deciding when to rebalance the workload abstracts all of these factors. The ability to tier gives the customer greater flexibility in selecting products that provide the correct combination of performance and capacity for their environment since any of the factors above could be relevant to creating differences in latency between PS Series members in a pool. For example, combining large capacity PS65x0 class arrays with lower capacity PS60x0 arrays using disks that provide higher I/O to get better total system ROI may be the appropriate design for some customers. Others might choose to combine members with 10K SAS and members with SSD to meet their application workload requirements. Many other configurations are possible, these are simply examples.
End of Sale or End of Life…What Exactly Does That Mean…?
Every six to nine months or so, Dell EqualLogic will release a new EqualLogic product line. Heck, some of you might even still have an EqualLogic PS300E or PS5000E. Out with the old and in with the new…right?
Wrong!
That’s the beauty of an EqualLogic iSCSI SAN solution. You never tear out, rip-out-and-replace, or forklift upgrade your storage area network (SAN). Remember that old PS50E or PS100E? Keep it! The EqualLogic iSCSI SAN architecture is built to add and expand what you currently have to the newer models.
So, when EqualLogic announces an “End of Sale” on their current product line, it simply means that they’re phasing into the new product line and that the old product line (in this case, the EqualLogic S4000, PS6000, PS6010, PS6510, and PS6500 series) will no longer be actively sold or positioned.
In fact, Dell EqualLogic still has a good amount of inventory left on the PS4000, PS6000, PS6010, PS6510, and PS6500 units, all of which still maintain aggressive EqualLogic pricing models. Once Dell ceases manufacturing parts for a particular EqualLogic product line, then this product becomes “End of Life.”
But please note that support for these products will NEVER diminish. Ever. Best advice? Keep up with your ProSupport contracts through Dell EqualLogic. Get these renewed each and every year because if you ever get into a position where you have a very old EqualLogic iSCSI SAN array that needs a replacement part, Dell EqualLogic MUST send you the replacement part or upgrade your entire array at no charge. Not bad, eh?
So, keep that old EqualLogic array in your network…and buy that new one, virtually add it to your existing group or use the old one to replicate to…either way, it’s still good.
Do I stay Gigabit or go 10GigE with my EqualLogic SAN…?
Going to a Gigabit Ethernet network from a 10/100 Ethernet network (Remember those days…?) was fairly easy. But if you think a migration to 10GigE is going to be just as easy, think again…
Don’t get me wrong. I’m all for getting more juice to the network, and the Dell EqualLogic iSCSI SANs come in a variety of 10GigE flavors. But before you jump into buying that 10GigE EqualLogic SAN you found on the self-service EqualLogic Pricing website, let’s share a few strategies that may help you maximize your Gigabit Ethernet network right now before taking the plunge into 10GigE.
1) Do you really need the extra bandwidth…?
2) What applications are driving the need to move in this direction…?
3) What kind of 10GigE interfaces are you looking to support…? And do you have the right connectors and cables to support this…? (fiber vs. copper, Cat 6a or better cables, etc.)
4) Have you looked into the cost of 10GigE NIC cards for your servers and other hardware on the network that may need this…?
5) Do you need more than 10 meters distance from the array…? (10GigE SFP limit)
6) Do you have the dough for all of this…?
So, now that you’ve justified the cost for a 10GigE network and have been eyeballing that cool EqualLogic PS6010E, PS6010X, PS6010XV, or PS6510E array from the EqualLogic Pricing website, here’s the cool stuff:
- Dual 10GbE iSCSI controllers with two (2) SFP+ per controller
- All the same inherently advanced features you’ve come to love and respect through an EqualLogic SAN
- Complete redundancy
- Installation in under one hour
Sure, fibre channel has had 10Gig for years now…but can you install it in under one hour, have all of the advanced features embedded onto the array from day one and still have the same (if not better) performance than fibre channel…? No, I didn’t think so either…
EqualLogic SANs – Do I subnet or buy a switch?
So. You’re about to buy that EqualLogic SAN you’ve been dreaming about…probably through us, so that makes it even better. Remember, the one you saw on our Self-Service EqualLogic Pricing…?
Now, you’re faced with a tough question: Do I put my new EqualLogic iSCSI SAN on a separate VLAN or subnet or do I put it on its own network…? Hmmm…good question, so let’s take a look at some conditions that might drive you decision.
First, let’s take a look at your applications. Are the applications going onto your new EqualLogic SAN considered mission-critical? Is there already enough traffic on the network where adding iSCSI traffic might pose an unneeded demand? Are the data network switches on your network pretty old or not wire speed?
This might be a good indication that you should probably buy a switch that will be dedicated to your new EqualLogic SAN. There’s a few things you need to make sure your new network switch has if you’re going to maximize your EqualLogic SAN investment:
- Must have Flow Control
- Must support Jumbo Frames
- Must be standards-based
- Should be “iSCSI optimized”
- Should have prioritization (802.1q/p) and / or as many priority queues as you need
If you’re looking for a good-quality switch, then I’d recommend the Dell PowerConnect…they come in different flavors – both Gigabit and 10GigE, and they normally start at about $1,000. You can find them through EqualLogic pricing in our Self-Service EqualLogic Pricing website…just go to EqualLogic Miscellaneous section and you’ll see a few options.
Or, if you don’t have the money, you can always try to use your own existing data network switches. Heck, as long as they have all of the above features you should be good to go. But, hey, why not just buy a Dell PowerConnect along with that EqualLogic SAN…? The main reason: The colors will match and your iSCSI SAN will both shine with that Dell logo. Heck, that in and of itself should be reason enough…plus you’ll look cool buying that pure Dell solution. You know you want to…
Dell EqualLogic Multi-Tiering
Huh…? What’s multi-tiering…? Well, you may have heard about auto-tiering or automatic tiering or sub-volume tiering…thing like that. Same family…they practically do the same thing, so we’ll lump them all into the category of multi-tiering for now. Yeah, you can argue with me later about the details and differences, but for now…listen up.
I’m no techie, but I’m smart enough to know that some of you out there have some pretty big honkin’ applications and files out there. Whether it’s large image files, document imaging, clustering, whatever…you just want to wrap yourself up in that big Dell EqualLogic SAN fleece blanket and not have to wake up at 2:37am each night – drenched in a cold sweat – and worry about having to make it to the office so darn early to make sure those heavy files will get pushed through.
Voila!
The EqualLogic PS6000XVS and PS6010XVS iSCSI SAN arrays. You know that SAS normally does the trick, but you just need a bit more juice…but your boss can’t just justify spending money on a pure SSD-drive EqualLogic iSCSI SAN unit either, so you what do you do…? Of course…you go to our Self-Service EqualLogic Pricing page and get a quote on a hybrid – either the PS6000XVS (this one’s for GigE networks) or the PS6010XVS (this one’s for 10GigE). You’d want to use one of these arrays for:
- You run a strong variety of mixed applications in your network while each has its own heavy and demanding requirements
- Use with highly dynamic (“hot”) data-intensive applications
- Virtual desktop data / Virtual desktop implementations (VDI)
- Applications that have sporadic read / writes
The question is: What are your IOPS running and / or peaking at…? The EqualLogic XVS units you’ll find on our EqualLogic Pricing page will give you a strong blend of SSD and SAS drives, but let’s make sure you need the speed and performance before driving off with one, all right…? Give us a shout…we can help.
2011 EqualLogic Storage Forum and Conference
The cat is out of the bag! The dates for the next big EqualLogic Conference have been announced this evening via an email to previous attendees and others. I highly recommend that everyone marks their calendars and makes room in their budgets to attend this awesome and highly educational event. The conference will be held in Orlando, Florida at the Hilton Disney World resort and conference center on June 5th – 10th, 2011. I am very excited about about both the venue choice and the time frame chosen for the event. It will definitely be a great time of the year to visit Florida, especially for those of us who have had to suffer through a rough winter!
The last conference, which was held in San Diego, CA, was an excellent and highly educational event which included:
* A special presentation from Michael Dell
* An awesome exhibitor floor featuring Juniper, Veeam, Dell Servers, Kace, and others
* Hands on training classes with EqualLogic hardware
* Great presentations from some very intelligent EQL Engineers including: Will Urban, David Glynn, Said A Syed, Laz Vekiarides, Jerry Daugherty, Tony Ansley to name a few.
* Excellent Networking Environment amongst EQL customers
* Great food!!
If all of that isn’t enough to keep us happy, I have “heard” there will be a few new additions to this conference. I can’t mention any specifics, just keep an eye out for more information coming soon!
I hope everyone is able to attend the conference this time around, but if you cannot make it I look forward to providing great coverage from the event to showcase the great experience that Dell/EqualLogic presents. There will also be excellent coverage provided from the Dell TechCenter (@iSCSIKing @SanPenguin ,etc) and of course tons of coverage on Twitter under the #EQLConf hash tag. Also, I look forward to meeting many of my blog readers at the conference, I know many of you were unable to attend the previous conference due to budgets and time constraints, so now is the time to get your travel requests approved!
Do I really need ProSupport with my EqualLogic SAN…?
Well, you tell me. You and / or your company have just invested more money in an EqualLogic SAN than the cost of your own vehicle. Heck, probably several vehicles. In other words, you’ve invested – or are about to invest – a lot of money into a premium EqualLogic iSCSI SAN solution…a solution that actually does what it says it’s gonna do. So, yeah, you need ProSupport…but now a couple of questions arise:
What kind of ProSupport do I need…and how much does EqualLogic Support Cost?
Okay, let me break it down for you.
There are two major types of ProSupport – Mission-Critical (MC) and Next Business Day (NBD). From these two options, you have a choice between 1, 3, 4 or 5 years of ProSupport when you initially purchase your EqualLogic SAN in addition to different response times (2-hour, 4-hour, 6-hour).
So which do you choose…? Simple. Listen closely…actually, read closely…
Mission-Critical – select this option for one or multiple reasons:
- The EqualLogic SAN will be placed in a location where there will be no technical staff available to physically manage it
- Your organization has true mission-critical applications that rely heavily upon the EqualLogic SAN being up always…you know, the kinds of applications you’d get a pink slip for if they ever go down
- You simply need the peace of mind that someone will show up within two or four hours with spare EqualLogic parts and a red cape to come and save the day and fix it for you
- Your company can afford it, you have some free money (let’s talk…I can help you here…ha!) and / or your company simply has a business requirement that all applications be serviced with mission-critical support agreements
- Lack the technical confidence of changing out hot-swappable parts and would rather allocate just a bit more time on “other” projects
Next Business Day – select this option for one or multiple reasons:
- None of the above reasons under Mission-Critical really apply
- The location where the EqualLogic SAN is to be located is surrounded with technical gurus
- Your technical confidence and competence is through the roof
- You really don’t have the money for Mission-Critical…but, hey, don’t worry about it…most companies are in this spot as well…
- You like to get your hands dirty and exercise those technical skills once in a while…trust me, swapping out hot-swappable parts and configuring a SAN in under 20 minutes can be hard work…
That’s really just about it. But don’t forget…we have EqualLogic Pricing available through our self-service pricing model to give you the options. Honestly, Dell doesn’t do this…you know what they do…? They tuck the cost of ProSupport in with the cost of the array…we don’t do that, we give you ProSupport choices and break it out through our EqualLogic Pricing model. Give me a call or email…I’ll explain it all that ProSupport stuff to you from what’s in it, the differences, etc. All of it.
And, oh, there’s another reason why you need ProSupport. Dell requires it. Yup, that’s right…
The EqualLogic SAS vs. SATA Debate
Okay, so you tell me you need an EqualLogic iSCSI SAN SAS array. But do you really need a SAS array…? I mean, do you reeeeeeeally need a SAS array…? Let’s look at the facts and see if what you have and what you need match up…fair…?
There’s no doubt that you’ve heard that SAS is fast, right? Oh, yeah. In fact, EqualLogic SAS units are extremely fast and have been known (and documented) to even outperform their fibre channel counterparts. Take that, fibre channel!!!
The SAS EqualLogic iSCSI SAN units can come in 10K or 15K RPM drive speeds within the EqualLogic PS4000X, PS4000XV, PS6000X, PS6000XV, PS6010X and PS6010XV models. For the EqualLogic PS6500X and PS6510X models, only 10K RPM drive speeds are available…for now.
So, let’s take a look at what you have. Hmmm…you have some file data and maybe some Exchange and SQL. Yes, database applications are usually pretty demanding and may merit faster drive speeds…SAS would definitely do the trick…
However…
Have you done a perfmon yet…? What’s a perfmon you might ask…? It stands for Performance Monitor (perfmon), and it’s a tool that helps you assess the (storage) traffic on your network. It’ll show you how many IOPS (Input/Output Operations Per Second) your network is pushing through, where your peak traffic times are and all that good stuff. Federal Appliance happens to coordinate these for free for our clients in an attempt to more accurately assess which EqualLogic iSCSI SAN you might need…whether it’s a SAS or a SATA.
Rule of thumb?
If your IOPS are more than 600 or so, you might want to consider a SAS unit. If it’s under this, you might be better off staying with a SATA unit. Why pay for more horsepower than your network really needs…? SAS does cost more…about 20% to 40%, on average, but if you don’t need it don’t buy it. I have plenty of clients running multiple database applications in their environment across an EqualLogic SATA unit…and it’s more than enough for them. Every client is different.
But there are other circumstances that might drive the need for an EqualLogic SAS unit over a SATA one…such as file size, imaging requirements, disaster recovery, replication needs, additional database applications, SAP implementations, ERP implementations, Oracle, DB2, clustering, future growth, and so on.
Still not sure with EqualLogic SAN is right for you…? Neither am I…heck, that’s why we need to talk. Now. Until we discuss your requirements and assess your traffic with a perfmon or some other network tool, we really won’t know for sure. But knowing what you need will help you build a business case for that EqualLogic SAN you’ve always wanted. You know, that nice new EqualLogic PS6000XV-9.6TB array that those financial tightwads in upper management declined last year…? Well, now you’ve got ammo…so go ahead, buy that PS6000XV-9.6TB…we’ve got your back…
The EqualLogic PS4000 vs. PS6000 Argument
One of the first questions I get from clients who look into the Dell EqualLogic PS6000 series is “Why is it so expensive…?” (get a self-service EqualLogic price quote here if you want to compare yourself).
This question is normally posed shortly after they strive to recover from a five-minute bout of sticker shock as I aid them in readjusting their jaw (which has fallen to the floor by this time…). But this question is a valid one…I mean, you can get the same capacity in the EqualLogic PS4000 for about 30% less cha-ching…so what’s the difference…?
First, I tell my clients to look at their company’s needs and answer a few questions:
- How much growth are you experiencing year-by-year?
- How much data do you acquire year-by-year?
- What (database) applications are you running?
- Are you looking to do Disaster Recovery or deploy an iSCSI SAN in multiple locations?
- How many Gigabit Ethernet ports do you really need from your EqualLogic SAN?
- What are you looking to accomplish long-term with your iSCSI SAN?
Here’s the bottomline…and maybe even a rule of thumb: 1) If your organization is not going to be growing and / or adding tons of data over the next 3 to 5 years, 2) don’t need anymore than two (2) Gigabit Ethernet ports for management into your EqualLogic iSCSI SAN, 3) don’t foresee pooling anymore than two physical EqualLogic arrays into one logical SAN for each location, then I’d say go for an EqualLogic PS4000E (or PS4000X or PS4000XV, depending on your applications and IOPS).
The EqualLogic PS4000 series is going to have about 30% to 40% less horsepower than the EqualLogic PS6000 series will produce, so if you can settle for that and tuck away the pride (cough, cough…), the EqualLogic PS4000 series will not only be more cost effective but will probably meet your requirements as well. Plus, it still has all the bells and whistles the big boy (PS6000 series) has.
If you have the slightest doubt about any of the above criteria, then don’t compromise your organization’s storage needs and consider the EqualLogic PS6000. Which do we recommend…? The PS6000 series, of course…it’s more money…I mean, it’s more flexible and more powerful and you don’t have to worry about any limitations. But, hey, it’s your budget and storage area network…figure out your needs and go from there…
Tony Gonzales
Sales & Technical Manager
Federal Appliance, LLC
www.FederalAppliance.com
EqualLogic Business Continuity and Disaster Recovery
EqualLogic, with its all-inclusive enterprise-class iSCSI SANs virtualized storage arrays, enables IT administrators with the technology and tools to build out affordable and easily manageable business continuity and disaster recovery solutions. With built-in snapshot, replica, clone, and replication features, along with partnerships with industry leading technology partners, EqualLogic simplifies the planning, deployment, and maintenance of an IT infrastructure that ensures that your business is fully protected and always operational.
BC/DR has traditionally been necessary, but too complex and expensive
Disaster recovery beyond backup was not affordable for most organizations when Fibre Channel SANs were the only option. Complex configurations including communication network extension equipment, add-on software, and staff training has been prohibitively expensive. Recent compliance regulations (e.g., HIPAA, Sarbanes-Oxley, and SEC rules) have pressured organizations of all sizes to make more data quickly recoverable for longer periods of time; company files, databases, and e-mail must be restorable for years. And with the proliferation of 24X7 business operations, companies of all sizes are recognizing the requirement to have a complete business continuity and disaster recovery environment to ensure that their IT operations are completely protected against natural and unnatural disasters and outages.
With storage consolidated on EqualLogic PS Series arrays, business continuity and disaster recovery is now affordable, fast, and simple. EqualLogic iSCSI SANs leverage your existing IP based LAN and WAN networking assets and competencies without requiring any add-on software or costly staff training. The PS Series’ Auto-Replication capability, standard in each array, provides point-in-time periodic replication to multiple remote sites. This method, easy to set up and operate, delivers multiple restore points and application-consistent copies that can be restored in minutes.
Check out our Online Dell EqualLogic Pricing to see how EqualLogic brings enterprise class data management services to small and medium sized businesses.
