Tag Archives: Cisco

Making cisco MDS switches log to an external (syslog) server

Cisco MDS

Configuring a Cisco SAN switch to have it send logging to an external syslog server by using the GUI is quite easy to do:

Floow the steps as I walk through DM: click “logs”, then “syslog”, then “setup”

If any syslog server is already configured, you’ll find it here:

You can either delete an existing or create a new entry, but you cannot have more than three entries in total!

If you prefer to have an entry using IPv4 or IPv6, choose IPv4 or IPv6, otherwise use DNS and simply type in its name.

I’ve tried this method to change an existing entry and somehow it wouldn’t stick. Deleting three entries, clicking refresh and 2 came right back…. I failed back to the command line.

The CLI is actually easier, but with less overview of what you’re doing. If you need to list the existing syslog servers, type “show logging”. In the extensive sum-up that follows are the servers you’ve configured so far. If a servers needs to be adjusted, don’t bother to first delete it, because a new entry will overwrite the existing line. But if you need to actually delete one, type “no logging server” followed by its name or IP.

A new entry is made by typing

logging server name-of-the-syslog-server.domainname.extension [severity] port 6514 facility syslog

if you want to use the IP of the server, don’t type its name, but the IP, the syntax is the same. Severity is for example “6” so any message of severity “notice(6)” and lower (more important) will be sent. I’ve put port 6514 here as an example for secure syslog, but any other port will do just fine as well.

If you want thee syslog server entries, repeat the “logging server” line three times, one for each syslog target.

Oh, don’t forget to ask the firewall admin to open the port that you will be using 😉

Don’t forget to save the new config. That’s it!

Troubleshooting error-disabled issues between a Cisco UCS fabric interconnect and a Cisco MDS

Cisco MDS

When connecting a high speed cisco UCS Fabric Interconnect (like the 6454) to Cisco MDS Fibre Channel switches, you might encounter error-disabled ports causing the port-channel to go down. Specifically for 8 Gbps speeds you need to enter 1 additional command per port that’s participating in the port-channel:

int fc1/17
switchport fill-pattern IDLE speed 8000

For each fc port on the MDS you need to enter this command, followed by a “shut / no shut” and the error disabled problems are most likely gone.

Check to see the port config:

show run int fc1/17

Or whatever port you configured to use the fill-pattern.

Source: Cisco

How to upgrade a Cisco MDS SAN switch

Cisco MDS

After a few years of not having had to perform switch upgrades, I had to perform a few firmware upgrades on MDS switches. I decided to write down the steps I had to take:

  • First make sure you have a reachable ftp server somewhere and write down its ip address
  • Log on to the Cisco MDS SAN switch you need to upgrade
  • Make sure the bootflash: has enough available space to hold the 2 new files

# dir bootflash:

4096 Feb 23 14:58:04 2020 lost+found/
26049024 Feb 10 12:57:55 2020 m9100-s5ek9-kickstart-mz.8.3.2.bin
121121564 Feb 10 12:56:47 2020 m9100-s5ek9-mz.8.3.2.bin

Usage for bootflash://sup-local
463962112 bytes used
2894815232 bytes free
3358777344 bytes total

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Cisco MDS CLI commands when checking for defects or signal degradation

Cisco MDS

Checking the environment of a switch:

  • show environment temp = what are the temperatures of the intake(s) and outlet(s)
  • show environment power = are the PSUs still working fine?
  • show environment fan = are the fans still working fine?

Checking for errors and signal degradation

  • show interface fc1/10 counters = show all standard counters for port fc1/10
  • show interface fc1/10 counters details = show the detailed counters for port fc1/10
  • show interface counters = show all standard counters for all ports
  • show interface detail-counters = show the detailed counters for all ports
  • show interface detail-counters | i CRC = show the detailed counters for all ports which contain the text “CRC”
  • show interface transceiver calibrations = show the specs of all SFPs
  • show interface transceiver details = show the specs and power details of all SFPs
  • show interface transceiver details | i “x Power” = show the current Rx/Tx power of all SFPs

Common knowledges dictates that fiber optice patches need to be cleaned with proper equipment to prevent unnecessary signal loss. See this blog post for more details on how and why to keep optic cables clean.

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:


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]#

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