Uncategorized, vnx2

Change Control Station IP for VNX

The installation of a VNX2

The first day is the toughest and easiest. Like baking a cake you need to make sure all the ingredients are there and ready to go. You verify what  was ordered is installed and is in working order. Sounds simple enough?

As it turns out the initial VNX “Rack and Stack” was correct.

  • All cables were plugged in correctly
  • No amber lights on the system.
  • The DAE (Disk Assembly Enclosures) were recognized.
  • No faults in Unisphere

Ok. Good to go? No? Why. Mr. Customer provided a duplicate IP for one of the control stations. The correct IP is the same subnet and mask but needs to be changed.

Here are the steps

  1. Log onto Unisphere confirm IP information for Control Station
  2. Log onto Control station via ssh

Use root/nasadmin (default)

3. Verify status of Control station. You can make changes to the primary not standby.

In this case the primary Control station was IP’d correctly. I need to change the secondary Control station, the standby.

/nasmcd/getreason  <<– run this command as root

Here is what you will see:

10 – slot_0 primary control station
11 – slot_1 secondary control station
 5 – slot_2 contacted
 5 – slot_3 contacted
4. Failover the Control station with this command:
    /nasmcd/sbin/cs_standby -failover
About 5 minutes later you will reboot the primary and failover to the secondary. 
5. Run this: /nasmcd/getreason
11 – slot_0 secondary control station
10 – slot_1 primary control station
 5 – slot_2 contacted
 5 – slot_3 contacted

6. Log into Unisphere

Normally you login to the VNX with using the primary Control Station IP. However since it is in failover mode use the secondary IP. In this case I am using the duplicate IP and will change it to the correct IP by using the Unisphere GUI

Screen Shot 2016-02-19 at 5.10.39 PM

Log into the Unisphere GUI as root. Make sure you choose scope “local” not Global

Navigate to the “Control station Properties Tab”

Screen Shot 2016-02-19 at 5.11.43 PM

Change the IP of the Control Station

Screen Shot 2016-02-19 at 5.12.20 PM


Click Apply.

In Confirm Action, click OK.


Modifying the Control Station hostname, IP address, subnet mask, or gateway may disrupt the Unisphere software connection and any other client access to the Control Station. It may be necessary to reconnect to continue administrative activities. If you make a mistake changing the network, the Control Station may no longer be reachable remotely.

7. ssh to the primary Control station and failback. Verify that the primary control station is in slot 0

#  /nasmcd/getreason
10 – slot_0 primary control station
11 – slot_1 secondary control station
 5 – slot_2 contacted
 5 – slot_3 contacted

That is it.


Remember when you login to Unisphere you connect via the Primary Control Station IP, if you are failed over you will connect to the secondary Control Station.


Thanks for reading! If you have a more efficient way please share. Yes, you can ssh in and do all of this via cli. 😉




EMC, hot spare, vnx, vnx2

HOT HOT HOT… Hot Spare that is! VNX VNX2

The other day I had a customer purchase a brand new DAE for his VNX.. awesome.. A full shelf of 25 drives.  900 GB SAS drives 2.5″ form factor.  Well do some quick math.. you have 5 R5 groups (4+1)

But… what a sec.. What about hot spare? You can run parity and have R5 for protection.. but you still need to be in compliance with your hot spare policy.  This customer has the older 3.5″ DAE (15 slots) and the newer drives are 2.5 ” .. what to do..

Will you have a valid hot spare on hand?

After some online research:

Based on the discussion and the reference white papers for both VNX and VNX2 – drive size isn’t of importance. The other factors are: drive type and density. VNX2 is global and won’t take into consideration the drive speed, so you could potentially have slower speed drive of same type for a replacement. This is unknown to the Admin as the policy is set differently.

https://community.emc.com/thread/123197?start=0&tstart=0  — A great discussion about this and a fantastic resource for EMC related issues. The following is take from the above thread.
Hot spare algorithm
The appropriate hot spare is chosen from the provisioned hot spares algorithmically.  If there were no hot spares provisioned of appropriate type and size when a drive fails, no rebuild occurs.  (See the Drive Rebuilds section.)  The RAID group with the failed drive remains in a degraded state until the failed drive is replaced; then the failed drive’s RAID group rebuilds.
The hot spare selection process uses the following criteria in order:
  1. Failing drive in-use capacity – The smallest capacity hot spare drive that can accommodate the in-use capacity of the failing drive’s LUNs will be used.
  2. Hot spare location – Hot spares on the same back-end port as the failing drive are preferred over other like-size hot spares.
  3. Same Drive type – Hot spare must be of the same drive type.
Failing drive in-use capacity
It is the in-use capacity of the failing drive’s that determines the capacity of the hot spare candidates.  Note this is a LUN-dependent criterion, not a raw drive capacity dependency.  This is measured by totalling the capacity of the drive’s bound LUNs.  The in-use capacity of a failing drive’s LUNs is not predictable.  This rule can lead to an unlikely hot spare selection.  For example, it is possible for a smaller capacity hot spare to be automatically selected over a hot spare drive identical to, and adjacent to the failing drive in the same DAE.  This occurs because the formatted capacity of the smaller, hot spare (the highest-order selection criteria) matches the in-use capacity of the failing drive’s LUNs more closely than the identical hot spare drive.
Note that a hot spare’s form factor and speed are not a hot spare criteria within the type.
For example, a 3.5” format 15K rpm drive can be a hot spare for a failing 2.5” 10K rpm SAS drive.
For the VNX2


Bottom line this is good to know because the customer had open slots in their existing 15 slot 3.5 ” DAE and if drive form factor did matter they would need to buy another DAE for the 2.5″ drives!

Here is the Hot Spare drive matrix. It illustrates the Failed drive and compatible spare.