Posts Tagged ‘FC’

Merging Brocade Fabrics

February 23, 2016

fibreRecently I needed to merge two pairs of Brocade fibre channel fabrics for one of the customers. When I was doing a bit of my own research I realised that there is very scarce information on how to do that on the Interwebs. There were a few community posts on the Brocade forums, but there seemed to be some confusion around how zoning should be configured to let the switches merge successfully. I thought I would fill the gap with this post and share my own experience.


First, make sure you have the right transceivers. Short wave 8Gb FC transceivers are limited to 190m when using OM4 fibre. If you need to connect switches over a longer distance, use long wave SFP+ modules, which have maximum distance of 10km.

Second, change the default switch Domain IDs. All switches within the same fabric must have unique IDs. By default Brocade switches come with the Domain ID set to 1. If you’re merging two redundant fabrics, make sure that the second pair of the switches have Domain IDs set to 2.

Third, verify that the switches you’re interconnecting have compatible zoning configuration. Brocade is very specific on how zoning should be configured for two fabrics to merge. There are at least nine different scenarios, but we’ll touch only on three most common ones. If you want to get more details, refer to the Brocade Fabric OS Administrator’s Guide and specifically the section called “Zone merging scenarios”.

Zone merging scenarios

Scenario 1: Switch A does not have a defined configuration. Switch B has a defined configuration.

This is the most straightforward scenario when you are adding a brand new Switch A to an existing fabric. As a result of the merge configuration from the Switch B propagates to the switch A.

Scenario 2: Switch A and Switch B have different defined configurations. Switch B has an effective configuration.

This is the scenario where you have two individual fabrics with their own set of aliases, zones and defined configurations. There is a catch here. If you want to merge such fabrics, you MUST have unique set of aliases, zones and configurations on each fabric. If this requirement is not met, fabrics won’t merge and you will end up with two segmented fabrics because of the zoning conflict. You also MUST disable effective zoning configuration on Switch A.

Outage is not required, because typically you have two redundant fabrics – fabric A and B in each location. And you can do one switch at a time. If you are still concerned, implement Scenario 3.

Scenario 3: Switch A and Switch B have the same defined and effective configuration.

This is the easiest path and is what Brocade calls a “clean merge”. Under this scenario you will have to recreate the same configs on both fabrics. That means you MUST have completely identical aliases, zones and configs on Switch A and Switch B.

This is the easiest and least disruptive path if you are worried that disabling effective configuration on the switches may cause issues.

Real world scenario

In my case I went with scenario 2 for two reasons: one – it was a DR site where I could temporarily bring down both fabrics and two – I didn’t need to manually add aliases/zones/configs to the switches as I would have to in scenario 3. Once fabrics are merged, zones from Switch B propagate to Switch A and you can simply combine them in one zone in the GUI, which is just a few mouse clicks.


Here is the step by step process. First step is to change Domain IDs on the second pair of switches. You can do that both from GUI and CLI. Bear in mind that even if you’ve picked scenario 3 as the least disruptive approach for merging zones, changing Domain IDs will still be disruptive. Because switch has to be disabled before making the change.

From the Web Tools go to Switch Administration, disable the switch in the Switch Status section, type in the new Domain ID and re-enable the switch:


If you want to take the CLI path, run the following. Switch will ask you a series of questions. You can accept all defaults, except for the Domain field:

> switchdisable
> configure
> switchenable
> fabricshow

Next disable the effective configuration on the Switch A either from GUI or CLI:

> cfgdisable
> cfgactvshow

At this point you can interconnect the switches and you should see the following log entry on Switch A:

The effective configuration has changed to SWITCHB_CONFIG

The fabrics are now merged an you should see both switches under the Web Tools. If you see the switch in the Segmented Switches section, it means that something went wrong:


Clean up steps

Once the fabrics are merged you will see all zones in the Zone Admin interface, however, the effective configuration will be configuration from the Switch B. You will need to create a new configuration which combines all zones to enable connectivity between the devices connected to the Switch A.

From the operational perspective you can now manage zoning on either of the switches and when you save or enable a configuration it will propagate to all switches in the fabric automatically.

If you have redundant fabrics, which you normally do, repeat the steps for the second pair of switches.


Steps described in this post are for a basic switch setup. If you have a non-standard switch configuration or using some of the advanced features, make sure to check “Zone Merging” section in the Fabric OS Administrator’s Guide for any additional considerations.

Let me know if this was helpful.



Masking a VMware LUN

February 7, 2016

maskingA month ago I passed my VCAP-DCA exam, which I blogged about in this post. And one of the DCA exam topics in the blueprint was LUN masking using PSA-related commands.

Being honest, I can hardly imagine a use case for this as LUN masking is always done on the storage array side. I’ve never seen LUN masking done on the hypervisor side before.

If you have a use case for host LUN masking leave me a comment below. I’d be curious to know. But regardless of its usefulness it’s in the exam, so we have to study it, right? So let’s get to it.


There are many blog posts on the Internet on how to do VMware LUN Masking, but only a few explain what is the exact behaviour after you type each of the commands and how to fix the issues, which you can potentially run into.

VMware uses Pluggable Storage Architecture (PSA) to claim devices on ESXi hosts. All hosts have one plug-in installed by default called Native Multipathing Plug-in (NMP) which claims all devices. Masking of a LUN is done by unclaiming it from NMP and claiming using a special plug-in called MASK_PATH.

Namespace “esxcli storage core claimrule add” is used to add new claim rules. The namespace accepts multiple ways of addressing a device. Most widely used are:

  • By device ID:
    • -t device -d naa.600601604550250018ea2d38073cdf11
  • By location:
    • -t location -A vmhba33 -C 0 -T 0 -L 2
  • By target:
    • -t target  -R iscsi -i -L 0
    • -t target -R fc –wwnn 50:06:01:60:ba:60:11:53 –wwpn 50:06:01:60:3a:60:11:53 (use double dash for wwnn and wwpn flags, WordPress strips them off)

To determine device names use the following command:

# esxcli storage core device list

To determine iSCSI device targets:

# esxcli iscsi session list

To determine FC paths, WWNNs and WWPNs:

# esxcli storage core path list

Mask an iSCSI LUN

Let’s take iSCSI as an example. To mask an iSCSI LUN add a new claim rule using MASK_PATH plug-in and addressing by target (for FC use an FC target instead):

# esxcli storage core claimrule add -r 102 -t target -R iscsi -i -L 0 -P MASK_PATH

Once the rule is added you MUST load it otherwise the rule will not work:

# esxcli storage core claimrule load

Now list the rules and make sure there is a “runtime” and a “file” rule. Without the file rule masking will not take effect:


The last step is to unclaim the device from the NMP plug-in which currently owns it and apply the new set of rules:

# esxcli storage core claiming unclaim -t location -A vmhba33 -C 0 -T 0 -L 0
# esxcli storage core claiming unclaim -t location -A vmhba33 -C 1 -T 0 -L 0
# esxcli storage core claimrule run

You can list devices connected to the host to confirm that the masked device is no longer in the list:

# esxcli storage core device list

Remove maskig

To remove masking, unclaim the device from MASK_PATH plug-in, delete the masking rule and reload/re-run the rule set:

# esxcli storage core claiming unclaim -t location -A vmhba33 -C 0 -T 0 -L 0
# esxcli storage core claiming unclaim -t location -A vmhba33 -C 1 -T 0 -L 0
# esxcli storage core claimrule remove -r 102
# esxcli storage core claimrule load
# esxcli storage core claimrule run

Sometimes you need to reboot the host for the device to reappear.


Make sure to always mask all targets/paths to the LUN, which is true for iSCSI as well as FC, as both support multipathing. You have a choice of masking by location, target and path (masking by device is not supported).

For a FC LUN, for instance, you may choose to mask the LUN by location. If you have two single port FC adapters in each host, you will typically be masking four paths per LUN.  To accomplish that specify adapters using flag -A and LUN ID using flags -C, -T and -L.

Hope that helps you to tick off this exam topic from the blueprint.

Traffic Load Balancing in Cisco UCS

December 21, 2015

Whenever I deploy a Cisco UCS at a customer the question I get asked a lot is how traffic flows within the system between VMs running on the blades and FEX modules, FEX modules and Fabric Interconnects and finally how it’s uplinked to the network core.

Cisco has a range of CNA cards for UCS blades. With VIC 1280 you get 8 x 10Gb ports split between two FEX modules for redundancy. And FEX modules on their own can have up to 8 x 10Gb Fabric Interconnect facing interfaces, which can give you up to 160Gb of bandwidth per chassis. And all these numbers may sound impressive, but unless you understand how your VMs traffic flows through UCS it’s easy to make wrong assumptions on what per VM and aggregate bandwidth you can achieve. So let’s dive deep into UCS and shed some light on how VM traffic is load-balanced within the system.

UCS Hardware Components

Each Fabric Extender (FEX) has external and internal ports. External FEX ports are patched to FIs and internal ports are internally wired to the blade adapters. FEX 2204 has 4 external and 16 internal and FEX 2208 has 8 external and 32 internal ports.

External ports are connected to FIs in powers of two: 1, 2, 4 or 8 ports per FEX and form a port channel (make sure to use “Port Channel” link grouping preference under Chassis/FEX Discovery Policy). Same rule is applied to blade Virtual Interface Cards (VIC). The most common VIC 1240 and 1280 have 4 x 10Gb and 8 x 10Gb ports respectively and also form a port channel to the internal FEX ports. Every VIC adaptor is connected to both FEX modules for redundancy.


Fabric Interconnects are then patched to your network core and FC Fabric (if you have one). Whether Ethernet uplinks will be individual uplinks or port channels will depend on your network topology. For fibre uplinks the rule of thumb is to patch FI A to your FC Fabric A and FI B to FC Fabric B, which follows the common FC traffic isolation principle.

Virtual Circuits

To provide network and storage connectivity to blades you create virtual NICs and virtual HBAs on each blade. Since internally UCS uses FCoE to transfer FC frames, both vNICs and vHBAs use the same 10GbE uplinks to send and receive traffic. Worth mentioning that Cisco uses Data Center Bridging (DCB) protocol with it’s sub-protocols Priority Flow Control (PFC) and Enhanced Transmission Selection (ETS), which guarantee that FC frames have higher priority in the queue and are processed first to ensure low latency. But I digress.

UCS assigns a virtual circuit to each virtual adaptor, which is a representation of how the traffic traverses the system all the way from the VIC port to a FEX internal port, then FEX external port, FI server port and finally a FI uplink. You can trace the full path of each virtual adaptor in UCS Manager by selecting a Service Profile and viewing the VIF Paths tab.


In this example we have a blade with four vNICs and two vHBAs which are split between two fabrics. All virtual adaptors on fabric A are connected through VIC port channel PC-1283 which is represented as port channel PC-1025 on the FEX A side. Then traffic leaves FEX A and reaches the Fabric Interconnect A which sends the traffic out to the network core through port channel A/PC-1.

You can also get the list of port channels from the FI CLI:

# connect nxos
# show port-channel summary


Network Load Balancing

Now that we know how all components are interconnected to each other, let’s discuss the traffic flow in a typical VMware environment and how we achieve the massive network throughput that UCS provides.

As an example let’s take a look at the vSwitch where your VM Network port group is configured. vSwitch will have two uplinks – one goes to Fabric A and the other one to Fabric B for redundancy. Default load balancing policy on a vSwitch is “Route based on the originating port ID”, which essentially pins all traffic for a VM to a particular uplink. vSphere makes sure that VMs are evenly distributed between the uplinks to use all network bandwidth available.

From each uplink (or vNIC in UCS world) traffic is forwarded through an adapter port channel to a FEX, then to a Fabric Interconnect and leaves UCS from a FI uplink. Within UCS traffic is distributed between port channel members using source/destination IP hash algorithm. Which is even more granular and is capable of very efficient traffic distribution between all members of a port channel all the way up to your network core.


If you look at the vSwitch you’ll see that with UCS each uplink shows the maximum available bandwidth from vNIC and is not limited to a port channel member speed of 10Gb. Why is this so powerful? Because with UCS you don’t need to slice adapter’s available bandwidth between different types of traffic. Even though you provision multiple vNICs and vHBAs for the vSphere hosts, UCS uses the same port channel links (20Gb in the example below) from the VIC adapter to transfer all traffic and takes care of load balancing for you.


You may legitimately ask, if UCS uses the same pipe to transfer all data regardless of which vSwitch uplink is being used, then how can I make sure that different types of traffic, such as vMotion, storage, VM traffic, replication, etc, do not compete for the same pipe? First you need to ask yourself if you can saturate that much bandwidth with your workloads. If the answer is yes, then you can use another great feature available in UCS, which is QoS. QoS lets you assign a minimum available bandwidth guarantee on a per vNIC/vHBA basis. But that’s a topic for another blog post.


In this post I tried to summarise the logic behind UCS traffic distribution. If you want to dig deeper in UCS network architecture, then there’re a lot of great bloggers out there. I would like to call out the following authors:


VNX/VNXe array negotiates FC port as L-Port

March 23, 2015

Hit an issue today where VNXe array FC ports negotiate to L-port instead of F-port when Fill Word is set to Mode 3 (ARB/ARB then IDLE/ARB). Result – loss of connectivity on the affected link.


Recommended FC Fill Word for VNX/VNXe arrays is Mode 3. Generally it’s a good idea to set them according to best practice as part of each installation. Apparently, when changing Fill Word from legacy Mode 0 (IDLE/IDLE) to Mode 3 (ARB/ARB then IDLE/ARB) array might negotiate as L-port and FC path goes down.

Solution is to statically configure port as F-port in port settings.



  • Dell M5424 8Gb Fibre Channel Switch: Brocade FOS v7.2.1b
  • EMC VNXe 3200: Block OE v3.1.1.4993502

Overview of NetApp Replication and HA features

August 9, 2013

NetApp has quite a bit of features related to replication and clustering:

  • HA pairs (including mirrored HA pairs)
  • Aggregate mirroring with SyncMirror
  • MetroCluster (Fabric and Stretched)
  • SnapMirror (Sync, Semi-Sync, Async)

It’s easy to get lost here. So lets try to understand what goes where.



SnapMirror is a volume level replication, which normally works over IP network (SnapMirror can work over FC but only with FC-VI cards and it is not widely used).

Asynchronous version of SnapMirror replicates data according to schedule. SnapMiror Sync uses NVLOGM shipping (described briefly in my previous post) to synchronously replicate data between two storage systems. SnapMirror Semi-Sync is in between and synchronizes writes on Consistency Point (CP) level.

SnapMirror provides protection from data corruption inside a volume. But with SnapMirror you don’t have automatic failover of any sort. You need to break SnapMirror relationship and present data to clients manually. Then resynchronize volumes when problem is fixed.


SyncMirror mirror aggregates and work on a RAID level. You can configure mirroring between two shelves of the same system and prevent an outage in case of a shelf failure.

SyncMirror uses a concept of plexes to describe mirrored copies of data. You have two plexes: plex0 and plex1. Each plex consists of disks from a separate pool: pool0 or pool1. Disks are assigned to pools depending on cabling. Disks in each of the pools must be in separate shelves to ensure high availability. Once shelves are cabled, you enable SyncMiror and create a mirrored aggregate using the following syntax:

> aggr create aggr_name -m -d disk-list -d disk-list

HA Pair

HA Pair is basically two controllers which both have connection to their own and partner shelves. When one of the controllers fails, the other one takes over. It’s called Cluster Failover (CFO). Controller NVRAMs are mirrored over NVRAM interconnect link. So even the data which hasn’t been committed to disks isn’t lost.


MetroCluster provides failover on a storage system level. It uses the same SyncMirror feature beneath it to mirror data between two storage systems (instead of two shelves of the same system as in pure SyncMirror implementation). Now even if a storage controller fails together with all of its storage, you are safe. The other system takes over and continues to service requests.

HA Pair can’t failover when disk shelf fails, because partner doesn’t have a copy to service requests from.

Mirrored HA Pair

You can think of a Mirrored HA Pair as HA Pair with SyncMirror between the systems. You can implement almost the same configuration on HA pair with SyncMirror inside (not between) the system. Because the odds of the whole storage system (controller + shelves) going down is highly unlike. But it can give you more peace of mind if it’s mirrored between two system.

It cannot failover like MetroCluster, when one of the storage systems goes down. The whole process is manual. The reasonable question here is why it cannot failover if it has a copy of all the data? Because MetroCluster is a separate functionality, which performs all the checks and carry out a cutover to a mirror. It’s called Cluster Failover on Disaster (CFOD). SyncMirror is only a mirroring facility and doesn’t even know that cluster exists.

Further Reading

Monitoring ESX Storage Queues

July 30, 2013

6a00d8341c328153ef01774354e2fd970d-500wiQueue Limits

I/O data goes through several storage queues on its way to disk drives. VMware is responsible for VM queue, LUN queue and HBA queue. VM and LUN queues are usually equal to 32 operations. It means that each ESX host at any moment can have no more than 32 active operations to a LUN. Same is true for VMs. Each VM can have as many as 32 active operations to a datastore. And if multiple VMs share the same datastore, their combined I/O flow can’t go over the 32 operations limit (per LUN queue for QLogic HBAs has been increased from 32 to 64 operations in vSphere 5). HBA queue size is much bigger and can hold several thousand operations (4096 for QLogic, however I can see in my config that driver is configured with 1014 operations).

Queue Monitoring

You can monitor storage queues of ESX host from the console. Run “esxtop”, press “d” to view disk adapter stats, then press “f” to open fields selection and add Queue Stats by pressing “d”.

AQLEN column will show the queue depth of the storage adapter. CMDS/s is the real-time number of IOPS. DAVG is the latency which comes from the frame traversing through the “driver – HBA – fabric – array SP” path and should be less than 20ms. Otherwise it means that storage is not coping. KAVG shows the time which operation spent in hypervisor kernel queue and should be less than 2ms.

Press “u” to see disk device statistics. Press “f” to open the add or remove fields dialog and select Queue Stats “f”. Here you’ll see a number of active (ACTV) and queue (QUED) operations per LUN.  %USD is the queue load. If you’re hitting 100 in %USD and see operations under QUED column, then again it means that your storage cannot manage the load an you need to redistribute your workload between spindles.

Some useful documents:

NetApp thin-provisioning for VMware LUNs

May 22, 2013


LUN and Volume Thin Provisioning

I already described thin provisioning of VMware NFS volumes some time ago here. Now I want to discuss thin provisioning of LUNs.

LUNs are different from VMFS on top of NFS implementation, because LUN is an additional container inside of NetApp FlexVol. So if you’re using FC, you need to thin provision both LUN and volume:

> lun set reservation “/vol/targetvol/targetlun” disable
> vol options “targetvol” guarantee none

In fact, you can make the LUN thin and the volume thick. Then storage space that’s not used by the LUN, is returned to the volume level. But in this case it cannot be used by other volumes as a shared pool of space.

As the best practice, NetApp now recommends to set Fractional Reserve and Snap Reserve for your volumes to 0%. Don’t forget about that, if you want to save more storage space:

> vol options “targetvol” fractional_reserve 0
> snap reserve “targetvol” 0

Disable snapshots if you don’t use them:

> snap sched “targetvol” 0

It’s easy as that. Now you don’t waste your space by reserving it ahead, but use it as a shared pool of resources. But make sure to monitor aggregate free space. If you starting to run out of storage, plan purchase of new disks in advance or redistribute data between other aggregates.

Safety Features

Disabling volume level, LUN and snapshot reservations helps you to save storage space. The drawback of this approach is that you don’t have any mechanisms in place to prevent volume out-of-space situations. If you enable snapshots on the volume and they consume all the volume space, the volume goes offline. Very undesirable consequence. NetApp has two features that can serve as safety net in thin-provisioned environments: autosize and snap autodelete.

Snap autodelete automatically removes old snapshots if there is no space left inside the volume. Autosize, on the other hand, allows the volume to automatically grow to the specified limit (+20% to the volume size by default) in specified increments (5% of the volume size by the default). You can also specify what to do first autosize or snapshot autodelete by using ‘try_first’ option.

> snap autodelete “targetvol” on
> vol autosize “targetvol” on
> vol options “targetvol” try_first volume_grow

SnapMirror Considerations

If you use SnapMirroring and switch on the autosize on the source volume, then the destination volume won’t grow automatically. And SnapMirror will break the relationship if it runs out of space on the smaller destination volume. The trick here is to make the destination volume as big as the autosize limit for the source volume and thin provision the destination volume. By doing that you won’t run out of space on destination even if the source volume grows to its maximum.

Further reading

TR-3965: NetApp Thin Provisioning Deployment and Implementation Guide Data ONTAP 8.1 7-Mode

Jumbo Frames justified?

March 27, 2012

When it comes to VMware on NetApp, boosting  performance by implementing Jumbo Frames is always taken into consideration. However, it’s not clear if it really has any significant impact on latency and throughput.

Officially VMware doesn’t support Jumbo Frames for NAS and iSCSI. It means that using Jumbo Frames to transfer storage traffic from VMkernel interface to your storage system is the solution which is not tested by VMware, however, it actually works. To use Jumbo Frames you need to activate them throughout the whole communication path: OS, virtual NIC (change to Enchanced vmxnet from E1000), Virtual Switch and VMkernel, physical ethernet switch and storage. It’s a lot of work to do and it’s disruptive at some points, which is not a good idea for production infrastructure. So I decided to take a look at benchmarks, before deciding to spend a great amount of time and effort on it.

VMware and NetApp has a TR-3808-0110 technical report which is called “VMware vSphere and ESX 3.5 Multiprotocol Performance Comparison Using FC, iSCSI, and NFS”. Section 2.2 clearly states that:

  • Using NFS with jumbo frames enabled using both Gigabit and 10GbE generated overall performance that was comparable to that observed using NFS without jumbo frames and required approximately 6% to 20% fewer ESX CPU resources compared to using NFS without jumbo frames, depending on the test configuration.
  • Using iSCSI with jumbo frames enabled using both Gigabit and 10GbE generated overall performance that was comparable to slightly lower than that observed using iSCSI without jumbo and required approximately 12% to 20% fewer ESX CPU resources compared to using iSCSI without jumbo frames depending on the test configuration.
Another important statement here is:
  • Due to the smaller request sizes used in the workloads, it was not expected that enabling jumbo frames would improve overall performance.

I believe that 4K and 8K packet sizes are fair in case of virtual infrastructure. Maybe if you move large amounts of data through your virtual machines it will make sense for you, but I feel like it’s not reasonable to implement Jumbo Frames for virual infrastructure in general.

The another report finding is that Jumbo Frames decrease CPU load, but if you use TOE NICs, then no sense once again.

VMware supports jumbo frames with the following NICs: Intel (82546, 82571), Broadcom (5708, 5706, 5709), Netxen (NXB-10GXxR, NXB-10GCX4), and Neterion (Xframe, Xframe II, Xframe E). We use Broadcom NetXtreme II BCM5708 and Intel 82571EB, so Jumbo Frames implementation is not going to be a problem. Maybe I’ll try to test it by myself when I’ll have some free time.

Links I found useful:

Random DC pictures

January 19, 2012

Several pictures of server room hardware with no particular topic.

Click pictures to enlarge.


UPS’s Network Management Card (NMC) (with temperature sensor) connected to LAN.

Here you can see battery extenders (white plugs). They allow UPS to support 5kVA of load for 30 mins.

Two Dell PowerEdge 1950 server with 8 cores and 16GB RAM each configured as VMware High Availability (HA) cluster.

Each server has 3 virtual LANs. Each virtual LAN has its own NIC which in its turn has multi-path connection to Cisco switch by two cables, 6 cables in total.

Two Cisco switches which maintain LAN connections for NetApp filers, Dell servers, Sun tape library and APC NMC card. Two switches are tied together by optic cable. Uplink is a 2Gb/s trunk.

HP rack with 9 HP ProLiant servers, HP autoloader and MSA 1500 storage.

HP autoloader with 8 cartridges.

HP MSA 1500 storage which is completely FC.

Hellova cables.

NetApp Guts

October 15, 2011

Today I took several pictures of our NetApp FAS3020 Active/Active cluster to give you an idea of what NetApp essentially is from hardware point of view.

Here are some highlights of FAS3020 series:

  • Maximum Raw Capacity: 84TB
  • Maximum Disk Drives (FC, SATA, or mix): 168
  • Controller Architecture: 32-bit
  • Cache Memory: 4GB
  • Maximum Fibre Channel Ports: 20
  • Maximum Ethernet Ports: 24
  • Storage Protocols: FCP, iSCSI, NFS, CIFS

General view.

Click pictures to enlarge.

Two filers in active/active high availability cluster configuration. In case of one filer failure second takes over without lost of service.

Filers are connected to four disk shelves 15 TB in total. First pair is populated with Fibre Channel hardrives (DS14mk4 FC) and second with SATA (DS14mk2 AT). You can see FC drives on picture below.

Even though NetApp supports iSCSI it’s a NAS in nature. Each filer has four FC ports for disk shelves connectivity 0a throught 0d and four GE ports for network connections e0a thorugh e0d.

Filers are connected with two cluster interconnect cables which very much resembles InfiniBand. This interconnect is used for HA heartbeat.

Meters of FC cables.

Power is connected to 10000VA APC. Power cables are tied up to prevent accidental unhooking.

Here is the NetApp motherboard which has two CPU sockets and four memory slots.

NetApp chassis also includes two power supplies, two fan modules, LCD display and backplane which ties everything up.

FC shelves are equipped with ESH4 modules and AT with AT-FCX.