Category Archives: Configuration - Page 2

Cisco MDS NX-OS zoning on the CLI

Cisco MDS

The Cisco Fabric Manager or the newer DCNM can be great for creating a limited number of zones and aliases, but when the number of zones exceeds 10 or 20 or so, creating, cloning and editing these can be a pain in the [email protected]

FC-SWITCH-01# conf t
Enter configuration commands, one per line. End with CNTL/Z.


Create aliases:

FC-SWITCH-01(config)# fcalias name VM101-HBA1 vsan 45
FC-SWITCH-01(config)# member pwwn 20:21:22:25:B6:00:00:01

Enhanced zone session has been created. Please ‘commit’ the changes when done.


FC-SWITCH-01(config-fcalias)# fcalias name VM101-HBA1 vsan 45
FC-SWITCH-01(config-fcalias)# member pwwn 20:21:22:25:B6:00:00:02
FC-SWITCH-01(config-fcalias)# fcalias name VM102-HBA1 vsan 45
FC-SWITCH-01(config-fcalias)# member pwwn 20:21:22:25:B6:00:00:03

FC-SWITCH-01(config-fcalias)# device-alias commit

Create two new zones:

FC-SWITCH-01(config-zone)# zone name VM101-HBA1_VNX-5600-08-SPA6 vsan 45
FC-SWITCH-01(config-zone)# member fcalias VNX5600-08-SPA6
FC-SWITCH-01(config-zone)# member fcalias VM101-HBA1
FC-SWITCH-01(config-zone)# zone name VM102-HBA1_VNX-5600-08-SPB7 vsan 45
FC-SWITCH-01(config-zone)# member fcalias VNX5600-08-SPB7
FC-SWITCH-01(config-zone)# member fcalias VM102-HBA1
FC-SWITCH-01(config-zone)# zone commit vsan 45

Commit operation initiated. Check zone status

Now add the two new zones to a zoneset:

FC-SWITCH-01(config)# zoneset name ZS_VSAN170 vsan 45
FC-SWITCH-01(config-zoneset)# member VM101-HBA1_VNX-5600-08-SPA6
FC-SWITCH-01(config-zoneset)# member VM102-HBA1_VNX-5600-08-SPB7
FC-SWITCH-01(config-zoneset)# zone commit vsan 45


Maximum distances using fiber cable types OM1/OM2/OM3/OM4/OS1

What are the maximum distances using different fiber grades?


fiber cable specs graph

The graphs show the direction where OM-specs are going compared to distances.

Read more »

Cisco MDS: Fabric is already locked

Cisco MDS

When you encounter a fabric lock, because you accidentally left the GUI or CLI without committing the changes, you can try the following to clear the lock and retry to apply your changes:

  1. run ‘show cfs lock’ to see who lock`s the fabric
  2. run ‘clear device-alias session’ to clear the lock when you were doing zoning activities

Instead of the “clear device-alias session” in line 2, another common possibility to get the lock cleared is:

  • ‘clear ivr session’ (when you were in the middle of IVR activities)

Other locks can occur, but the device-alias and ivr are probably the most common. At least the ones that I encountered so far.

Cisco zoning: some commonly used – show – commands

Cisco MDS

When you need to look up the current zoning config of a Cisco SAN-switch / VSAN, there’s a number of commands that will help you. Because a “show run” doesn’t always do the trick well, especially if you have a large config. And using the “sh run | i “some text you’re looking for” doesn’t always help as well if you don’t know the exact phrase you’re looking for.

I hope this table helps:

show Command
show zone Displays zone information for all VSANs.
show zone vsan 100 Displays zone information for VSAN 100.
show zoneset vsan 100 Displays information for the zone set in VSAN 100.
show zoneset vsan 2-5 Displays configured zone set information for a range of VSANs (2, 3, 4 and 5 in this case).
show zone name AZone Displays members of zone “AZONE”.
show fcalias vsan 100 Displays fcalias configuration in VSAN 100.
show zone member pwwn 20:00:00:25:b1:34:aa:c2 Displays membership status of a port wwn. Very good if you’re concerned that 1 HBA is used in more than 1 zone!
show zone statistics Displays zone statistics.
show zone statistics read-only-zoning Displays read-only zoning statistics.
show zoneset active Displays the active zone sets.
show zoneset brief Displays brief descriptions of zone sets.
show zone active Displays the active zones.
show zone status Displays zone status.
show zone Displays zone statistics.
show running Displays the interface-based zones.

How to get started setting up ESRS on the latest OE for Block and MCx codes

It’s just another short post on a single command again. This time I was looking for an easy way to get started on ESRS on the latest OE for Block code or the newer MCx code (33.071 or newer).

First of all you need to set up DNS in your VNX machine. In Unisphere, go to settings and click on “configure DNS”.

Also, if there’s a firewall blocking internet traffic, you need to make sure the storage processors can reach * over tcp ports 443 and 8443.

After this you can use the following command on the CLI:

naviseccli -h [SPx ip#] esrsconfig -agentProvision -user [Online Support logon name] –password [Online Support super secret password]

Repeat this for the other SP as well.

Read more »

Cisco Smart Zoning: is it really worth the effort? YES!

It’s been available since NX-OS 5.2(6), but is the community ready for a change? It seems the majority of SAN managers are still afraid to start using it, but why? the concept is so simple: it looks like the infamous “default zone” has made it’s way back to the storage area network, but with a twist.

Default zoning

When I was introduced to the world of Fibre Channel, over ten years ago, I remember going through the automatic steps of setting up a freshly powered-on SAN-switch and disabling the default zone, because that one makes that all initiators and targets can communicate with each other. And two initiators talking to each other is not done, because on the midrange arrays an initiator (used for data replication) can also be a target and you don’t want ports logging into each other.

Read more »

Optimizing performance using VAAI and the ESX MaxHWTransferSize setting

xcopy transfer size

If you’re running an EMC VNX using a lower version than block OE version, you might want to upgrade to the latest and greatest version (patch 209 or newer). The 209 offers EMC’s latest fixes and enhancements for VAAI performance. Many of the found performance issues have been fixed in the 209 code. However, in some environments sub-optimal performance has been detected with xcopy operations, or in some cases with the performance of non-xcopy IO during xcopy operations to the same pool.

Read more »

How to change the VNX weekly heartbeat date and time

Changing the time for the weekly heartbeat

People with Clariion or VNX systems installed on site know that these arrays will email “home” (that’s EMC/you) once a week on a seemingly random date/time. Ok, once the day of the week and the time are set, each week the “I’m still alive” email will go out at that time. But what if you don’t want to have that email sent out at Thursday at 2:47AM and you want all of your arrays to send out that email on Saturday at noon sharp? You will need to adjust the parameters. I didn’t find a way to change the weekday, so I’m changing the time less than a day before it needs to run. So if I want it to run on Saturday at noon, I could run this script on Friday after noon. It will pick the next available day automatically.

Read more »

Configuring timezone and NTP on a Cisco MDS switch

Timezone and NTP configuration of a Cisco MDS switch

Using a GUI for configuring purposes isn’t always the best thing to do, although it most certainly provides a level of overview that cannot be obtained on the CLI.

I’ve found out the Device Manager default settings for NTP for example are that IPv4 addresses used to point to an NTP entity is set to “peer” and if you don’t use peer synchronization, but have a dedicated NTP server instead, it’s better to place a check mark on the “server” item. Also if you have several time sources, you can set a preferred one by placing a check mark at the particular entity.

Read more »

Fixing misalignment without moving data

Fixing misaligned partitions

It’s quite an old topic, but I recently found a great tool which allows you to re-align partitions without the need to manually move data from the misaligned disk to a new aligned disk.

First of all I must add that all the credits go to Nicholas Weaver, since he wrote the original blog and the actual tool!

Read more »

How to translate Windows disk ids to storage array’s LUNs

Converting disk information in a VM into the actual LUN information

We’ve all been there: you have a certain Windows virtual machine with several disks of the same size and you don’t know which Windows-disk is in fact which storage LUN.

The VMware settings for this VM might look like this:


Read more »

Which Hot Spare will be used for a failed drive? – part 2

Hard Drive

A while ago I talked about Hot Spares and how they are picked when a rebuild is necessary. It was almost 2 years ago and you can read it here.

Since then the rebuild / equalize technology has changed! Well, not for existing systems, but the new VNX family aka VNX2 does things a bit differently.

In the old days when a drive failed, a suitable Hot spare would kick in and the unprotected LUNs (regarding the failed drive) would be rebuild onto the Hot Spare. After a while, when the rebuild was done and the failed drive was replaced by a replacement drive, the data on the Hot spare would need to be copied to that new drive. This was called equalizing.

In the VNX2 (with MCx) this last step doesn’t exist anymore. So that means the Hot spare that was used to contain the rebuilt data is not longer a Hot Spare! It has become a regular drive! And that replacement drive will now be a new Hot Spare. When configuring a new VNX2 you’d see rules about Hot Spares and you simply don’t even need to configure Hot Spares anymore. Just make sure you have some unconfigured drives and you’re good. Your VNX2 will make sure they’re used as Hot Spares from then on.

If I remember correctly the DMX4 had a similar feature back in 2008, but it now flowed to the midrange platform as well.


How to set the “The array is alive” on a specific day and time on a VNX

The need for weekly messages

EMC’s Symmetrix already knew this feature for a decade or so (or even longer), but since a few years EMC’s pushing customers to make every array to email home once a week so they can keep track of its pulse. And they’re not joking about its importance either, since once an array skips a beat, a severity 1 ticket is being created to get that fixed as soon as possible. EMC truly seems to care about the arrays they have running all over the world, so they’re indeed in good shape and being monitored actively.

Read more »

EMC World 2013 – day 4

A little late, but better late than never. This last EMC World post has been sitting in my drafts, knowing two of my coleagues already posted theirs about the exact same thing that I wanted to talk about. And since I don’t want to play copy cat, I’m going to refer to their posts. That seems the best thing to do.

EMC World 2013, day 4

Thursday is traditionally (half) a day to say goodbye to the many old and new friends, visit some last day sessions, leave the hotel and head back to the airport, but this year I planned ahead and I decided to stay a bit longer for some quality time with the EMC Elect: My plane wouldn’t leave until Saturday afternoon!! I had to switch hotels though from the fancy and luxurious Venetian to the hotel next door “Harrah’s”. It’s a huge step down, but Harrah’s does what it’s supposed to do and that’s offering me a bed to sleep.

Read more »

Live VMware datastore expansion with running VMs

How to enlarge datastore capacity in Virtual Center?

There are several ways to get more disk storage available for your VMs running on VMware ESX. Adding an extra datastore is an option, but having multiple datastores creates an extra administrative overhead since you now have multiple datastores to monitor.

Another option is to simply extend an existing datastore. Live!

Read more »

Migrating hosts to new storage ports, LIVE

Migrating hosts to new storage ports, LIVE!

Many SAN administrators will face this challenge from time to time: certain hosts need to start using new storage ports. Reasons vary, but in the EMC Clariion/VNX world this might happen because it’s decided to dedicate the mirrorview ports to mirrorview only instead of allowing hosts to use these ports as well. Obviously having dedicated replication ports will improve replication performance and for synchronous replication this will also improve the production host performance since the write acknowledgement from the remote array will be quicker and the extra latency is limited to a minimum.
So you end up wanting to free the SPA1 and SPB1 ports (most Clarrions) or SPA0 and SPB0 (VNX). But disalowing hosts to use these ports means they will loose access to these paths. This just might be disruptive! Or not?

There’s a way to migrate nondisruptively!

Read more »

VMware: “adaptive queue depth” setting

What is the recommended LUN queue depth throttling in VMware ESX/ESXi?

According to EMC this “adaptive queue depth” setting is not yet supported (June 2013). The full article can be found on this link. It is known as Primus solution id emc279718.

My advice would be not to use this setting until EMC certifies this setting for use with their arrays.

The exact Article is as follows:

What is the recommended LUN queue depth throttling in VMware ESX/ESXi?
  • Need to know QFullThreshold,QFullSampleSize & Queue Fulls values for VMware.
  • Host Connectivity Guide does not include any standard values.
  • Performance issues.
OS: VMware ESX / ESXi
Product: CLARiiON / Symmetrix and I assume VNX as well
According to Engineering, enabling the adaptive queue depth algorithm is NOT documented in the Host Connectivity Guide or the EMC Support Matrix.
The recommendation is to use the default setting which is disable adaptive queue depth.
Additional checks with E-Lab VMware quality engineers, E-Lab testing is done with the default setting.
See emc274169 for additional information and or changes.  Also see these two documents on support pages or Powerlink.Using EMC VNX Storage with VMware VsphereUsing EMC Clariion Storage with Vmware Vsphere & VMware Infracture Version 4.0

Other useful features of USM

Techs focussed on EMC will know “EMC USM” for its use in upgrading storage arrays like Clariion and VNX as well as disk firmwares and installing enablers, but it can be used for other purposes as well.

Gearoid Griffin, a fellow EMC Elect 2013 member, wrote a nice article about it. Go have a look, I find it very interesting!

You can find his article on

EMC SAN Copy best practices

SAN Copy zoningEMC SAN Copy best practices

  • Just like with MirrorView ports: don’t use SC ports as host front end ports. Try to use dedicated ports for SC
  • Make sure the zoning is correct between the source SAN Copy port and the target SAN Copy port
  • Don’t use zones with multiple storage array (initiator) ports in them. Try to use SIST whenever you can: Single Initiator, Single Target so you’re certain there can only be 1 initiator in each zone

Read more »

the community is about helping each other: partition table lost and found


  • 1 Windows 2008R2 server containing 2 HBAs
  • 2 SAN switches
  • EMC VNX-5100
  • 1 LUN presented over 4 paths (2 per HBA)
  • no PowerPath or MPIO, so Windows host sees 4 vdisks and uses only 1 (with the risk of corruption)


After an unexpected reboot the host lost access to the data on the LUN and it seemed as if the vdisk was unformatted or at least corrupted.

  • I checked the VNX, but all 4 paths were available
  • “diskpart” showed the disk, but no volumes, so Windows people thought it was a “SAN issue” (which it wasn’t, of course)
  • I tried enabling MPIO, but by default this host made the LUN (now visible as 1 vdisk instead of 4) read only
  • After disabling MPIO I installed PowerPath (unlicensed) to be sure Windows only sees 1 vdisk instead of 4
  • After the reboot I once again saw 1 vdisk and PowerPath showed 4 paths (of which 2 unlicensed)
  • Still no luck accessing the data

the Community starts here

And here is where it gets interesting. The strength of the community is where you help each other and in this case the customer called me to inform me that since he had nothing to loose anyway he used “TestDisk by CGSecurity” and this tool actually discovers data patterns on disks and in the blink of an eye NTFS was found and the partition could be restored.

No format and restore of an earlier backup was necessary!