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Does your Building Block need a Fabric? <- Part 6
Okay, so this is all well and good, but you have been reading these posts and thinking that your environment is nowhere near the size of my example so Building Blocks are not for you. The fact is you can make individual Building Blocks quite a bit smaller or larger than the example I used in these posts and I’ll use a couple more quick examples to illustrate.
Small Environment: In this example, we’ll break down a 150 VM environment into three Building Blocks to provide the availability benefit of multiple isolated blocks. Additional Building Blocks can be deployed as the environment grows.
150 Total VMs deployed over 12 months
(2 vCPUs/32GB Disk/1GB RAM/25 IOPS per VM)
- 300 vCPUs
- 150GB RAM
- 4800 GB Disk Space
- 3750 Host IOPS
Assuming 3 Building Blocks, each Building Block would look something like this:
- 50 VMs per Building Block
- 2 x Dual CPU – 6 Core Servers (Maintains the 4:1 vCPU to Physical thread ratio)
- 24-32GB RAM per server
- 19 x 300GB 10K disks in RAID10 (including spares) — any VNXe or VNX model will be fine for this
- >1600GB Usable disk space (this disk config provides more disk space and performance than required)
- >1250 Host IOPS
Very Large Environment: In this example, we’ll scale up to 45,000 VMs using sixteen Building Blocks to provide the availability benefit of multiple isolated blocks. Additional Building Blocks can be deployed as the environment grows.
45000 Total VMs deployed over 48 months
(2 vCPUs/32GB Disk/4GB RAM/50 IOPS per VM)
- 90000 vCPUs
- 180,000 GB RAM
- 1,440,000 GB Disk Space
- 2,250,000 Host IOPS
Assuming 4 Building blocks per year, each Building Block would look something like this:
- 2812 VMs per Building Block
- 18 x Quad CPU – 10 Core Servera plus Hyperthreading (Maintains the 4:1 vCPU to Physical thread ratio)
- 640GB Ram per server
- 1216 x 300GB 15K disks in RAID10 (including spares) — one EMC Symmetrix VMAX for each Building Block
- >90000GB Usable disk space (the 300GB disks are the smallest available but still too big and will provide quite a bit more space than the 90TB required. This would be a good candidate for EMC FASTVP sub-LUN tiering along with a few SSD disks, which would likely reduce the overall cost)
- >140,000 Host IOPS
Hopefully this series of posts have shown that the Building Block approach is very flexible and can be adapted to fit a variety of different environments. Customers with environments ranging from very small to very large can tune individual Building Block designs for their needs to gain the advantages of isolated, repeatable deployments, and better long term use of capital.
Finally, if you find the benefits of the Building Block approach appealing, but would rather not deal with the integration of each Building Block, talk with a VCE representative about VBlock which provides all of the benefits I’ve discussed but in a pre-integrated, plug-and-play product with a single support organization supporting the entire solution.
Does your Building Block need a Fabric? <- Part 6
You may have noticed in the last installment that I did not include any FibreChannel switches in the example BOM. There are essentially three ways to deal with the SAN connectivity in a Building Block and there are advantages as well as disadvantages to each. (Note: this applies to iSCSI as well)
1.) Use switches that already exist in your datacenter: You can attach each storage array and each server back to a common fabric that you already have (or that you build as part of the project) and zone each of the Building Block’s servers to their respective storage array.
- Leverage any existing fabric equipment to reduce costs and centralize management
- Allow for additional servers to be added to each Building Block in the future
- Allow for presenting storage from one Building Block to servers in a different Building Block (useful for migrations)
- Increases complexity – Requires you to configure zoning within each Building Block during deployment
- Increases chances for human error that could cause an outage – Accidentally deleting entire Zonesets or VSANs is not as uncommon as you might think
- Reduces the availability isolation between Building Blocks – The fabric itself becomes a point-of-failure common to all Building Blocks.
2.) Deploy a dedicated fabric within each Building Block: Since each Building Block has a known quantity of storage and server ports, you can easily add a dual-switch/fabric into the design. In our example of 9 hosts you’d need a total of 18 ports for hosts and maybe 8 ports for the storage array for a combined total of 26 switch ports. Two 16-port switches can easily accommodate that requirement.
- Depending on the switches used, it could allow for additional servers in each Building Block in the future
- Allow for presenting storage from one Building Block to servers in a different building block (useful for migrations) by connecting ISLs between Building Blocks
- Maintains the Building Block isolation by not sharing the fabric switches across Building Blocks.
- Increases complexity – Requires you to configure zoning within each Building Block during deployment
- Increases chances for human error that could cause an outage – Again, accidentally deleting entire Zonesets or VSANs is not as uncommon as you might think
3.) Dispense with the fabric entirely: Since Building Blocks are relatively small, resulting in fewer total initiator/target pairs, it’s possible in some cases to directly attach all of the hosts to the storage array. In our example, the nine hosts need eighteen ports and the VNX5700 supports up to twenty four FC ports. This means you can directly attach all of the hosts to the array and still have six remaining ports on the array for replication, etc. Different arrays from EMC as well as other vendors will have various limits on the number of FC ports supported. Also, not all vendors support direct attached hosts so you’ll need to check that with your storage vendor of choice to be sure.
- Maintains the Building Block isolation by not sharing the fabric switches across Building Blocks.
- Simplifies deployment by eliminating the need to do any zoning at all and effectively eliminates any port queue limits (HBA elevator depth settings)
- Simplifies troubleshooting by eliminating the fabric (buffer to buffer credits, bandwidth, port errors, etc) from the IO path.
- Limits the number of hosts per Building Block by the maximum number of ports supported by the storage array.
- More difficult to non-disruptively migrate VMs between Building Blocks since storage cannot be shared across. (If all Building Blocks are in the same Virtual Data Center in VMWare vSphere, you can still live-migrate VMs via the IP network between Building Blocks using Storage vMotion)
If you decide that the host count limit is okay, and either non-disruptive migration between Building Blocks is unnecessary or Storage vMotion will work for you, then eliminating the fabric can reduce cost and complexity, while improving overall availability and time to deploy. If you need the flexibility of a fabric, I personally like using dedicated switches in each building block. Cisco and Brocade both offer 1U switches with up to 48 ports per switch that will work quite well. Always deploy two switches (as two fabrics) in each Building Block for redundancy.
Okay, so you’ve managed to calculate the size of your environment, how much time it will take you to virtualize it, the number of Building Blocks you need, and the specifications for each Building Block, including whether you need a fabric. Now you can submit your budget, get your final quotes, and place orders. Once the equipment arrives it’s time to implement the solution.
When your first Building Block arrives, it would be a valuable use of time to learn how to script the configuration for each component in the Building Block. An EMC VNX array can be completely configured using Naviseccli or PowerShell, from the Storage Pool and LUN provisioning to initiator registration and Host/LUN masking. VMWare vSphere can similarly be configured using scripts or PowerShell. If you take the time to develop and test your scripts against your first Building Block, then you can use those scripts to quickly stand up each additional Building Block you deploy. Since future Building Blocks will be nearly identical, if not entirely identical, the scripts can speed your deployment time immensely.
EMC Navisphere/Unisphere CLI (for VNX) is documented fully in the VNX Command Line Interface (CLI) Reference for Block 1.0 A02. This document is available on EMC PowerLink at the following location:Home > Support > Technical Documentation and Advisories > Software ~ J-O ~ Documentation > Navisphere Management Suite > Maintenance/Administration
Be sure to leverage any storage vendor plug-ins available to you for your chosen hypervisor (VMWare, Hyper-V, etc) to improve visibility up and down the layers and reduce the number of management tools you need to use on a daily basis.
For example, EMC Unisphere Manager, the array management UI running on the VNX storage array, includes built-in integration with VMWare and other host operating systems. Unisphere Manager displays the VMFS datastores, RDMs, and VMs that are running on each LUN and a storage administrator can quickly search for VM names to help with management and/or troubleshooting tasks.
EMC also provides free downloadable plug-ins for VMWare vSphere and Hyper-V so server administrators can see what storage arrays and LUNs are behind their VMs and datastores. The plug-ins also allow administrators to provision new LUNs from the storage array through the plug-ins without needing access to the array management tools.
Depending on which storage vendor you choose, if you build a fabric-less Building Block, you may be able to do all of your server and storage administration from vCenter if you leverage the free plug-ins.
Now that we know we’ll be deploying about 562 VM’s per Building Block we can use the other metrics to determine the requirements for a single block.
- Since 562 VMs is about 12.5% of the 4500 total VMs, we then calculate 12.5% of the other metrics determined in the last post.
- 12.5% of 9000 vCPUs = 1125 vCPUs
- 12.5% of 4500GB RAM = 562GB RAM
- 12.5% of 225,000 IOPS = 28125 Host IOPS
- 12.5% of 562TB = 70TB Usable Disk capacity
First we’ll size the compute layer of the Building Block
- At 4:1 vCPUs per Physical CPU thread you’d want somewhere around 281 hardware threads per Building Block. Using 4-socket, 8-core servers (32 cores per server) you’d need about 9 physical servers per building block. The number of vCPUs per physical CPU thread affects the % CPU Ready time in VMWare vSphere/ESX environments.
- For 562GB of total RAM per Building Block, each server needs about 64GB of RAM
- Per standard best practices, a highly available server needs two HBAs, more than two can be advantageous with high IOPS loads.
Next, we’ll calculate the storage layer of the Building Block
- Assuming no cache hits, the backend disk load for 28,125 Host IOPS @ 50:50 read/write looks like the following:
- RAID10 : 28125/2 + 28125/2*2 = 42187 Disk IOPS
- RAID5 : 28125/2 + 28125/2*4 = 70312 Disk IOPS
- RAID6 : 28125/2 + 28125/2*6 = 98437 Disk IOPS
- If you calculate the number of disks required to meet the 70TB Usable in each RAID level, and the # of disks needed for both 10K RPM and 15K RPM disks to meet the IOPS for each RAID level, you’ll eventually find that for this specific example, using EMC Best Practices, 600GB 10K RPM SAS disks in RAID10 provides the least cost option (317 disks including hot spares). Since 10K RPM disks are also available in 2.5” sizes for some storage systems, this also provides the most compact solution in many cases (29 Rack Units for an EMC VNX storage array that has this configuration). In reality this is a very conservative configuration that ignores the benefits of storage array caching technologies and any other optimizations available, it’s essentially a worst case scenario and it would be beneficial to work with your storage vendor’s performance group to perform a more intelligent modeling of your workload.
- Finally, you’ll need to select a storage array model that meets the requirements. Within EMC’s portfolio, 317 disks necessitate an EMC VNX5700 which will also have more than enough CPU horsepower to handle the 28125 host IOPS requirement.
At this point you’ve determined the basic requirements for a single Building Block which you can use as a starting point to work with your vendors for further tuning and pricing. Your vendors may also propose various optimizations that can help save you money and/or improve performance such as block-level tiering or extended SSD/Flash based caching.
Example bill-of-materials (BOM):
- 9 x Quad-CPU/8-Core servers w/64GB RAM each
- 2 x Single port FibreChannel HBAs
- 1 x EMC VNX5700 Storage Array with 317 x 300GB 2.5” 10K SAS disks
Wait, where’s the fabric?
The key to sizing Building Blocks is to calculate the ratio between the compute and storage metrics. First you need to take a look at the total performance and disk space requirements for the whole environment, similar to the below example:
- Total # of Virtual Machines you expect to be hosting (example: 4500 VMs)
- Total Virtual CPUs assigned to all Guest VMs (average of 2 vCPUs per VM = 9000 vCPUs)
- Total Memory required across all Guest VMs (average of 1GB per VM = 4.5TB)
- Total Host IOPS needed at the array for all Guest VMs (average of 50 IOPS per VM = 225,000 Host IOPS)
- You will need to have a read/write ratio with this as well (we will use 50:50 for these examples)
- Total Disk Storage required for all Guest VMs. (average of 125GB per VM = 562TB)
Once you have the above data, you need to decide how many Building Blocks you want to have once the entire environment is built out. There are several things to consider in determining this number:
- How often you want to be deploying additional Building Blocks (more on this below)
- Your annual budget (I’m ignoring budget for this example, but your budget may limit the size of your deployment each year)
- How many VMs you think you can deploy in a year (we’ll use 2250 per year for a two year deployment)
Some of these are pretty subjective so your actual results will vary quite a bit, but based what I’ve seen I do have some recommendations.
- In order to take advantage of the availability isolation inherent in the Building Block approach, you’ll want to start with at least two Building Blocks and then add them one or two at a time depending on how you want to spread your server farms across the infrastructure.
- Depending on the size of each Building Block you may want to keep Building Block deployments down to one every 3-6 months. That gives you ample time to build each block correctly and hopefully leaves time between deployments to monitor and adjust the Building Blocks.
That said I’d lean toward 4 to 6 Building Blocks per year. Of course this is just my opinion and your mileage may vary. For our example of 4500 VMs over 2 years @ 4 Building Blocks per year. we’ll end up with 8 Building Blocks with about 562 VMs each.
Since server virtualization abstracts the physical hardware from the operating systems and applications, essential for Cloud Infrastructures (also known as Infrastructure-as-a-Service), it’s ideally suited for breaking down the physical infrastructure into Building Blocks. Put simply, Building Blocks are repeatable, pre-designed mixes of storage, CPU, and memory.
There are several advantages to the Building Block approach that I’ll point out here:
- Rather than dropping a huge amount of capital up front on the entire infrastructure you need over the long haul, some of which will not be used at first, you can start with a smaller capital outlay today, then make multiple similarly small capital purchases only as needed. Further, when the hardware in a single Building Block reaches the end of its life (for any number of reasons), only that one Building Block will need to be refreshed at that time rather than a wholesale replacement of the entire environment.
- In an environment where virtualization is a new endeavor, sizing the compute, memory, and storage required is really an educated guess. As each Building Block is consumed, the real-world performance can be analyzed and adjusted for future Building Blocks to more closely match your specific workload.
- Building Blocks are inherently isolated which creates natural performance and availability boundaries. This can be leveraged for web and application server farms by spreading nodes of each farm across multiple Building Blocks. In the event of a catastrophic failure of one Building Block, due to major software bug affecting the cluster or the failure of an entire storage array for some reason, nodes of the server farm not hosted on the failed Building Block will be unaffected.
- The list price for storage arrays and servers goes down over time. If your growth is similar to many of my customers, where full build out of the physical infrastructure will not be required until 2-3 years after the start of the project, the acquisition cost of each individual Building Block will decrease over time, saving you money overall.
- In many cases, and due to a variety of factors, the cost to upgrade a storage array is higher than the cost to purchase the capacity with a new array. Upgrades also add complexity, complicate asset depreciation, and warranty renewals. The Building Block approach eliminates the majority of upgrades and the associated complexity.
Each Building Block can be maintained in its original build state or upgraded independent of the other building blocks so, for example, you don’t have to worry about upgrading every server in your datacenter with new HBA drivers if you decide to upgrade the storage array firmware on one array. You would only need to upgrade the servers in that arrays’ Building Block.
You may be thinking that your environment is not large enough to use a Building Block approach, but the more I worked on this project, the more I realized that Building Blocks can be adjusted to fit even very small environments. I’ll go into that a bit more later.
Part 1 -> The Building Block Approach
As 2011 wraps up and I have a little time at home over the holidays, I’ve been reflecting on some of the customer projects I’ve worked on over the past year. Cloud computing and EMC’s vision for the ”Journey to the Private Cloud” have been hot topics this year and of the various projects I’ve worked on this past year, one stands out to me as something that could be used as a blueprint for others who want to deploy their own Private Cloud but may not know how to start.
I have been working with a customer with approximately 10,000 servers that support their business and for all intents had zero virtualization as recent as 2010. As most customers already know, they thought it would be good to begin virtualizing their environment to drive up asset utilization and flexibility while bringing down costs. In the past, they’ve experimented with multiple server virtualization solutions (such as VMWare ESX and Microsoft Hyper-V) with limited success and had all but abandoned the idea. A change in leadership in late 2010 brought a top-down initiative to virtualize wherever possible, but in order to instill confidence in virtualized environments within the various business units, the virtual infrastructure needed to be reliable and performant.
The customer spent the latter half of 2010 looking at their existing physical environment, finding that about 80% of the 10,000 servers were various application, file, and web servers; the remaining 20% being various database servers (mostly MS SQL). Moving an infrastructure this large into a Private Cloud model would take several years and, further adding to the challenge, the DBA teams were particularly wary about virtualizing their database servers. That said, the newly formed Virtualization and Cloud team set a goal of virtualizing the approximately 8,000 non-database servers over 36 months, starting out with dev/test and gradually adding production and tier-1 applications until only the database servers remained on physical infrastructure. They believe that if they prove success with virtualization during this first 3 years, the DBAs will be more willing to begin virtualizing their systems, plus there should be more knowledge and tools in the public domain for managing virtual database instances by then.
To accomplish all of their goals, the customer leveraged some experience that individual team members had gained from prior environments to come up with a Building Block based deployment. I worked with them to finalize the design and sizing for the each Building Block and throughout the year have helped analyze the performance of the deployed infrastructure to help determine how the Building Blocks can be optimized further. Through the next several posts, I will explain the Building Block approach, detailing the benefits, some of the considerations, and some thoughts around sizing. I hope that this information will be useful to others. The content is mostly vendor agnostic except for some example data that uses EMC specific storage best practices.
Part 1 -> The Building Block Approach
This past week, during EMC World 2010 in Boston, EMC made several announcements of updates to the Celerra and CLARiiON midrange platforms. Some of the most impressive were new capabilities coming to CLARiiON FLARE in just a couple short months. Major updates to Celerra DART will coincide with the FLARE updates and if you are already running CLARiiON CX4 hardware, or are evaluating CX4 (or Celerra), you will want to check these new features out. They will be available to existing CX4(120,240,480,960)/NS(120,480,960) systems as part of a software update.
Here’s a list of key changes in FLARE 30:
- Unified management for midrange storage platforms including CLARiiON and Celerra today, plus RecoverPoint, Replication Manager and more in the future. This is a true single pane of glass for monitoring AND managing SAN, NAS, and data protection and it’s built in to the platform. ”EMC Unisphere” replaces Navisphere Manager and Celerra Manager and supports multiple storage systems simultaneously in a single window. (Video Demo)
- Extremely large cache (ie: FASTCache) – Up to 2TB of additional read/write cache in CLARiiON using SSDs (Video Demo)
- Block level Fully Automated Storage Tiering (ie: sub-LUN FAST) – Fully automated assignment of data across multiple disk types
- Block Level Compression – Compress LUNs in the CLARiiON to reduce disk space requirements
- VAAI Support – Integrate with vSphere ESX for improved performance
These features are in addition to existing features like:
- Seamless and non-disruptive mobility of LUNs within a storage array – (via Virtual LUNs)
- Non-Disruptive Data Migration – (via PowerPath Migration Enabler)
- VMWare Aware Storage Management – (Navisphere, Unisphere, and vSphere Plugins giving complete visibility and self-service provisioning for VMWare admins (Video Demo) AND Storage Admins
- CIFS and NFS Compression – Compress production data on Celerra to reduce disk space requirements including VMs
- Dynamic SAN path load balancing – (via PowerPath)
- At-Rest-Encryption – (via PowerPath w/RSA)
- SSD, FC, and SATA drives in the same system – Balance performance and capacity as needed for your application
- Local and Remote replication with array level consistency – (SnapView, MirrorView, etc)
- Hot-swap, Hot-Add, Hot-Upgrade IO Modules – Upgrade connectivity for FC, FCoE, and iSCSI with no downtime
- Scale to 1.8PB of storage in a single system
- Simultaneously provide FC, iSCSI, MPFS, NFS, and CIFS access
All together, this is an impressive list of features for a single platform. In fact, while many of EMC’s competitors have similar features, none of them have all of them in the same platform, or leverage them all simultaneously to gain efficiency. When CLARiiON CX4 and Celerra NS are integrated and managed as a single Unified storage system with EMC Unisphere there is tremendous value as I’ll point out below…
Improve Performance easily…
- Install a couple SSD drives into a CLARiiON and enable FASTCache to increase the array’s read/write cache from the industry competive 4GB-32GB up to 2TB of array based non-volatile Read AND Write cache available to ALL applications including NAS data hosted by the array.
- Install PowerPath on Windows, Linux, Solaris, AND VMWare ESX hosts to automatically balance IO across all available paths to storage. PowerPath detects latency and queuing occuring on each path and adjusts automatically, improving performance at the storage array AND for your hosts. This is a huge benefit in VMWare environments especially.
- When VMWare releases the updated version of vSphere ESX that supports VAAI, ESX will be able to leverage VAAI support in the CLARiiON to reduce the amount of IO required to do many tasks, improving performance across the environment again.
- Upgrade from 1gbe iSCSI to 10gbe iSCSI, or from 4gbe FiberChannel to 8gbe FiberChannel, without a screwdriver or downtime.
- Provide NAS shared file access with block-level performance for any application using EMC’s MPFS protocol.
Improve Efficiency and cost easily…
- Create a single pool of storage containing some SSD, some FC, and some SATA drives, that automatically monitors and moves portions of data to the appropriate disk type to both improve performance AND decrease cost simultaneously.
- Non-disruptively compress volumes and/or files with a single click to save 50% of your disk space in many cases.
- Convert traditional LUNs to more efficient Thin-LUNs non-disruptively using PowerPath Migration Enabler, saving more disk space.
Increase and Manage Capacity easily…
- Add additional storage non-disruptively with SSD, FC, and SATA drives in any mix up to 1.8PB of raw storage in a single CLARiiON CX4.
- Using FASTCache, iSCSI, FC, and FCoE connectivity simultaneously does not reduce total capacity of the system.
- Expanding LUNs, RAID Groups, and Storage Pools is non-disruptive.
- Migrating LUNs between RAID groups and/or Storage Pools is non-disruptive using built-in CLARiiON LUN Migration, as is migrating data to a different storage array (using PowerPath Migration Enabler)!
- Balancing workload between storage processors is non-disruptive and at individual LUN granularity.
Protect your data easily…
- Snapshot, Clone, and Replicate any of the data to anywhere with built in array tools that can maintain complete data consistency across a single, or multiple applications without installing software.
- Maintain application consistency for Exchange, SQL, Oracle, SAP, and much more, even within VMWare VMs, while replicating to anywhere with a single pane-of-glass.
- Encrypt sensitive data seamlessly using PowerPath Encryption w/RSA.
- While you can do all of these things quickly and simply, you still have the flexibility to create traditional RAID sets using RAID 0, 1, 5, 6, and 10 where you need highly predicable performance, or tune read and write cache at the array and LUN level for specific workloads. Do you want read/write snapshots? How about full copy clones on completely separate disks for workload isolation and failure protection? What about the ability to rollback data to different points in time using snapshots without deleting any other snapshots? EMC Storage arrays have been able to do this for a long time and that hasn’t changed.
There are few manufacturers aside from EMC that can provide all of these capabilities, let alone provide them within a single platform. That’s the definition of simple, efficient, Unified Storage in my opinion.
Building on the redundant storage project, we also wanted to replicate Exchange to a remote datacenter for disaster recovery purposes. We’ve been using EMC CLARiiON MirrorView/A and Replication Manager for various applications up to now and decided we’d use NetApp/SnapMirror for Exchange to leverage the additional hardware as well as a way to evaluate NetApp’s replication functionality vs EMC’s.
On EMC Clariion storage, there are a couple choices for replicating applications like Exchange.
1.) Use MirrorView/Async with Consistency Groups to replicate Exchange databases in a crash-consistent state.
2.) Use EMC Replication Manager with Snapview snapshots and SANCopy/Incremental to update the remote site copy.
Whether using EMC RM or NetApp SM, software must be installed on all nodes in the Exchange cluster to quiesce the databases and initiate updates. The advantage of Consistency groups with MirrorView is that no software needs to be installed in the host; all work is performed within the storage array. The advantage of RM and SM/E is that database consistency is verified on each update and the software can coordinate restoring data to the same or alternate servers, which must be done manually if using MirrorView.
NetApp doesn’t support consistent snapshots across multiple volumes so the only option on a Filer is to use SnapManager for Exchange to coordinate snapshots and SnapMirror updates.
Our first attempt configuring SnapManager for Exchange actually failed when we ran into a compatibility issue with SnapDrive. SnapManager depends on SnapDrive for mapping LUNs between the host and filer, and to communicate with the filer to create snapshots, etc. We’d discussed our environment with NetApp and IBM ahead of time, specifically that we have Exchange CCR running on VMWare, with FiberChannel LUNs and everyone agreed that SnapDrive supports VMWare, Exchange, Microsoft Clustering, and VMWare Raw Devices. It turns out that SnapDrive 6 DOES support all of this, but not all at the same time. Specifically, MSCS clustering is not supported with FC Raw Devices on VMWare. In comparison, EMC’s Replication Manager has supported this configuration for quite a while. After further discussion NetApp confirmed that our environment was not supported in the current version of SnapDrive (6.0.2) and that SnapDrive 6.2, which was still in Beta, would resolve the issue.
Fast forward a couple months, SnapDrive 6.2 has been released and it does indeed support our environment so we’ve finally installed and configured SnapDrive and SnapManager. We’ve dedicated the EMC side of the Exchange environment for the active nodes and the IBM for the passive nodes. SnapManager snapshots the passive node databases, mounts them to run database verification, then updates the remote mirror using SnapMirror.
While SnapManager does do exactly what we need it to do, my experience with it hasn’t been great so far… First, SnapManager relies on Windows Task Scheduler to run scheduled jobs, which has been causing issues. The job will run on its schedule for a day, then stop after which the task must be edited to make it run again. This happens in the lab and on both of our production Exchange clusters. I also found a blog post about this same issue from someone else.
The other issue right now is that database verification takes a long time, due to the slow speed of ESEUTIL itself. A single update on one node takes about 4 hours (for about 1TB of Exchange data) so we haven’t been able to achieve our goal of a 2-hour replication RPO. IBM will be onsite next week to review our status and discuss any options. An update on this will follow once we find a solution to both issues. In the meantime I will post a comparison of replication tools between EMC and NetApp soon.
In the last post, I talked about a project I am involved in right now to deploy NetApp storage alongside EMC for SAN and NAS. Today, I’m going to talk about my first impressions of the NetApp during deployment and initial configuration.
I’m going to be pretty blunt — I have been working with EMC hardware and software for a while now, and I’m generally happy with the usability of their GUIs. Over that time, I’ve used several major revisions of Navisphere Manager and Celerra Manager, and even more minor revisions, and I’ve never actually found a UI bug. To be clear, EMC, IBM, NetApp, HDS, and every other vendor have bugs in their software, and they all do what they can to find and fix them quickly, but I just haven’t personally seen one in the EMC UIs despite using every feature offered by those systems. (I have come across bugs in the firmware)
Contrast that with the first day using the new NetApp, running the latest 188.8.131.52L1 code, where we discovered a UI problem in the first 10 minutes. When attempting to add disks to an aggregate in FilerView, we could not select FC disk to add. We could, however, add SATA disk to the FC aggregate. The only way to get around the issue was to use the CLI via SSH. As I mentioned in my previous post, our NetApp is actually an IBM nSeries, and IBM claims they perform additional QC before their customers get new NetApp code.
Shortly after that, we found a second UI issue in FilerView. When creating a new Initiator group, FilerView populates the initiator list with the WWNs that have logged in to it. Auto-populating is nice but the problem is that FilerView was incorrectly parsing the WWN of the server HBAs and populating the list with NodeWWNs rather than PortWWNs. We spent several hours trying to figure out why the ESX servers didn’t see any LUNs before we realized that the WWNs in the Initiator group were incorrect. Editing the 2nd digit on each one fixed the problem.
I find it interesting that these issues, which seemed easy to discover, made it through the QC process of two organizations. ONTap 7.3.2RC1 is available now, but I don’t know if these issues were addressed.
As far as FilerView goes, it is generally easy to use once you know how NetApp systems are provisioned. The biggest drawback in an HA-Filer setup is the fact you have to open FilerView separately for each Filer and configure each one as a separate storage system. Two HA-Filer pairs? Four FilerView windows. If you include the initial launch page that comes up before you get to the actual FilerView window, you double the number of browser windows open to manage your systems. NetApp likes to mention that they have unified management for NAS and SAN where EMC has two separate platforms, each with their own management tools. EMC treats the two storage processors (SPs) in a Clariion in a much more unified manner, and provisioning is done against the entire Clariion, not per SP. Further, Navisphere can manage many Clariions in the same UI. Celerra Manager acts similarly for EMC NAS. Six of one, half a dozen of the other some say, except that I find that I generally provision NAS storage and SAN storage at different times, and I’d rather have all of the controllers/filers in the same window than NAS and SAN in the same window. Just my preference.
I should mention, NetApp recently released System Manager 1.0 as a free download. This new admin tool does present all of the controllers in one view and may end up being a much better tool than FilerView. For now, it’s missing too many features to be used 100% of the time and it’s Windows only since it’s based on MMC. Which brings me to my other problem with managing the NetApp. Neither FilerView nor System Manager can actually do everything you might need to do, and that means you end up in the CLI, FREQUENTLY. I’m comfortable with CLIs and they are extremely powerful for troubleshooting problems, and especially for scripting batch changes, but I don’t like to be forced into the CLI for general administration. GUI based management helps prevent possibly crippling typos and can make visualizing your environment easier. During deployment, we kept going back and forth between FilerView and CLI to configure different things. Further, since we were using MultiStore (vFilers) for CIFS shares and disaster recovery, we were stuck in the CLI almost entirely because System Manager can’t even see vFilers, and FilerView can only create them and attach volumes.
Had I not been managing Celerra and Clariion for so long, I probably wouldn’t have noticed the above problems. After several years of configuring CIFS, NFS, iSCSI, Virtual DataMovers, IP Interfaces, Snapshots, Replication, and DR Failover, etc. on Celerra, as well as literally thousands of LUNs for hundreds of servers on Clariion, I don’t recall EVER being forced to use the CLI. CelerraCLI and NaviCLI are very powerful, and I have written many scripts leveraging them, and I’ll use CLI when troubleshooting an issue. But for every single feature I’ve ever used on the Celerra or Clarrion, I was able to completely configure from start to finish using the GUI. Installing a Celerra from scratch even uses a GUI based installation wizard. Comparing Clariion Storage Groups with NetApp Initiator groups and LUN maps isn’t even fair. For MS Exchange, I mapped about 50 LUNs to the ESX cluster, which took about 30 minutes in FilerView. On the Clariion, the same operation is done by just editing the Storage Group and checking each LUN, taking only a couple minutes for the entire process.
Now, all of the above commentary has to do with the management tools, UIs, and to some degree personal preferences, and does not have any bearing on the equipment or underlying functionality. There are, of course, optional management tools like Operations Manager, Provisioning Manager, and Protection Manager available from NetApp, just as there is Control Center from EMC (which incidentally can monitor the NetApp) or Command Central from Symantec. Depending on your overall needs, you may want to look at optional management tools; or, FilerView may be perfectly fine.
In the next post, I’ll get into more specifics about how the Exchange 2007 CCR cluster turned out in this new environment, along with some notes on making CCR truly redundant. I’ve also been working on the NAS side of the project, so I’ll also post about that some time soon.