Category Archives: Configuration - Page 2

How to enable a replica-LUN on Unity

EMC Unity

LUN-replication on Unity works slightly different than it previously did on VNX or even Clariion. In these older generations, when you deleted the mirrorview Mirror Group, both the primary and secondary LUNs became usable as separate entities.

In Unity the secondary LUN is a different beast. First of all: in Unity you can only set up replication from the primary Unity/LUN. The process on the source-Unity will create a LUN-replica and a replication session on both Unitys.

But what happens when you need hosts to access the secondary LUN? A failover works as designed and the previous secondary LUN becomes writable, but when you break the replication session, the replica-LUN has a flag that needs to be reset, but you’ll need the CLI to do that. This is how I did it:

  • In Unisphere I listed all LUNs and I made sure to include the “CLI ID” column
  • I noticed the ID of the LUN I need to grant access to is “res_56”
  • I started PUTTY and made sure logging to a file was configured so I could easily browse / search the possibly large amount of data some commands can produce, especially “-detail” commands tend to be very explicit
  • Log in as the “service” user to the Unity command line

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How to expand a LUN on VNX using the CLI

Once in a while you come across a storage system that cannot be managed through the GUI or you just want to script or use the CLI to perform management tasks on a VNX. Recently I came across an old VNX2 which GUI wasn’t responding the way I’d like, so I decided to use the CLI instead.

In this particular case I needed to expand a LUN.

First I listed the current size:

naviseccli -h [SPA/B ip#] -user [user] -password [password] -scope [scope] getlun [LUN#]

Then I expanded the LUN to the new size:

naviseccli -h [SPA/B ip#] -user [user] -password [password] -scope [scope] lun -expand -l [LUN#] -capacity [new capacity] -sq [mb/gb/tb/bc]

Pay attention to the number and the prefix! It could be a lot of work if you needed to resize a LUN from 50GB to 60GB and instead GB, you used TB…..

And finally I checked if the new size was actually available:

naviseccli -h [SPA/B ip#] -user [user] -password [password] -scope [scope] getlun [LUN#]

Sometimes CLI is so much easier than the GUI!

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How to remove an offline VNX from a Unisphere domain

When decommissioning a VNX, I recently forgot to remove the array from the existing domain. After the VNX was “unracked and unstacked” I saw my mistake and tried to remove it from the domain by using the “add/remove systems” in Unisphere, but the remove-button was grayed out. Even engineering mode didn’t help me.

There is another way to remove unwanted VNXs from a domain! You might have guessed it already, because it’s by using the command line!

First you’ll have to find out what existing VNX is the domain master. This can be done in Unisphere by looking up the current master. Click on “Domains” followed by “Select Domain Master”.

The outcome will show you the list of domain in the domain as well as the current master.

Now you can open a command line box and enter the following command to deleted the unwanted VNX from the domain:

naviseccli -Address -User -Password -Scope 2 domain -remove

Changing the time of Cisco DCNM

You’ve just deployed the DCNM appliance and you notice that the reports are displayed in the PDT timezone format. How do you change this into your own timezone?

For this you can log on to the command line of the appliance using SSH.

Check if DNS is working by performing a ping to your favorite NTP server.

To edit your timezone settings use your favorite editor (like “vi”).

vi /etc/ntp.conf

# Use public servers from the pool.ntp.org project.
# Please consider joining the pool (http://www.pool.ntp.org/join.html).
server 0.centos.pool.ntp.org iburst
server 1.centos.pool.ntp.org iburst
server 2.centos.pool.ntp.org iburst
server 3.centos.pool.ntp.org iburst

If you want to use your own NTP server, put a hashtag in front of the 4 example servers in the config file and put your own NTP server in.

# Use public servers from the pool.ntp.org project.
# Please consider joining the pool (http://www.pool.ntp.org/join.html).
ntp.mycompany.com iburst

The “iburst” parameter will try 8 times to collect new time info if necessary, instead of the default, which is only once per interval.

To change the timezone, remove the /etc/localtime file and create a new symbolic link to the file you need.

rm /etc/localtime

The list of location files can be found here:

/usr/share/zoneinfo

for example “Europe/Amsterdam” would be the file /usr/share/zoneinfo/Europe/Amsterdam. You can simply list the available locations by listing the available files in these folders.

ln -s /usr/share/zoneinfo/Europe/Amsterdam localtime

Now restart the NTP daemon:

service ntpd restart

And check the current date and time:

[email protected] etc]# date
Tue Jun 19 13:22:06 CEST 2018
[[email protected] etc]# date
Tue Jun 19 13:26:00 CEST 2018
[[email protected] etc]#

How to find out the LUN id of a Windows disk

Hard Drive

Attaching multiple LUNs to a Windows host and later trying to figure out which LUN is which can be a drag. I found out that using the “details disk” command in diskpart can help you finding backup the right LUN:

 

diskpart

list disk

select disk 19 (or whatever drive you want to see the details of)

detail disk

HITACHI DF600F  Multi-Path Disk Device
Disk ID: 00000000
Type   : FIBRE
Status : Online
Path   : 0
Target : 2
LUN ID : 7
Location Path : UNAVAILABLE
Current Read-only State : Yes
Read-only  : Yes
Boot Disk  : No
Pagefile Disk  : No
Hibernation File Disk  : No
Crashdump Disk  : No
Clustered Disk  : No

There are no volumes.

 

So in this particular case the Host LUN id was 7. This should help you along a bit 🙂