Saturday, September 29, 2012

Spaning Tree Protocol

It is always good to go back to the basics.

Spanning Tree Protocol (STP, RSTP, MSTP) is the protocol often overlooked in modern data center networks but it still has critical impact for operation excellence.

So here are few interesting links explains the basics:
Understanding STP and RSTP Convergence
How Are Evaluated Forward Delay and Max Age Timers in STP?

Monday, September 24, 2012

Friday, September 21, 2012

Top 10 What’s New Cool Features in Hyper-V 3

From a virtualization perspective, here’s the Top 10 What’s New Cool Features in Windows Server 2012 with Hyper-V—or just Hyper-V 3 for short.

1.    VMs with up to 32 vCPUs
2.    VMs with up to 512GB vRAM
3.    VHDX (=VMDK) up to 16TB
4.    Multiple concurrent Live Migrations & Live Storage Migrations
5.    Hyper-V Replicas (This + SC Orchestrator = SRM Replacement)
6.    Extensible Virtual Switch (There’s a 1000v for Hyper-V)
7.    63-Node Clusters
8.    Built-In NIC Teaming/Trunking & QoS
9.    VM Affinity Rules
10.    No dedicated Live Migration Network needed
11.    Hyper-V Client (This is Hyper-V inside Win8 for client-side virtualization!)


Saturday, September 15, 2012

Not able to install SqlServer 2008 says Restart computer failed?

Not able to install SqlServer 2008 says Restart computer failed?

I've found answer at
setup.exe /SkipRules=RebootRequiredCheck /ACTION=install

SNMP Trap Receiver on FreeBSD

Net-SNMP is the package for all SNMP operations. It can also acts as SNMP Trap Receiver.

First of all, it's good idea to read the section about traps in Net-SNMP Tutorial.

Step by step blog post about Sending and Receiving SNMP Traps in FreeBSD can be also found in

Test trap can be send by following command:
snmptrap -v 1 -c public localhost '' localhost 6 1 ''

The daemon for snmp trap receiver is snmptrapd which uses configuration file snmptrapd.conf

Here is example of snmptrapd.conf file:

# snmptrapd.conf
# SECTION: Output formatting for traps received.
#   Output from snmptrapd is formatted according to the
#   rules defined by the formatting configuration directives.

# format1: How SNMPv1 traps are formatted.
#   See the snmptrapd.conf manual page for format string details.
#   arguments: formatstring

format1 '%y-%m-%l ?%h:%j:%k ?%b ?%P ?%N ?%W ?%v\n'

# format2: How SNMPv2 and SNMPv3 traps are formatted.
#   See the snmptrapd.conf manual page for format string details.
#   arguments: formatstring

format2 '%y-%m-%l ?%h:%j:%k ?%b ?%P ?%N ?%W ?%v\n'

logOption f /var/log/snmptraps.log
ignoreauthfailure yes
disableAuthorization yes

Thursday, September 13, 2012

SAN Switch cheat sheet

B-Series (Brocade) switches uses both web and CLI, the table below displays some but not all the CLI commands.
help prints available commands
switchdisabled disable the switch
switchenable enable the switch
licensehelp license commands
diaghelp diagnostic commands
configure change switch parameters (BB credits, etc)
diagshow POST results since last boot
routehelp routing commands
switchshow display switch show (normally first command to run to obtain switch configuration)
supportshow full detailed switch info
portshow # display port info
nsshow namesever contents
nsallshow NS for full fabric
fabricshow Fabric information
version firmware code revision
reboot full reboot with POST
fastboot reboot without POST
B-Series (Brocade) zoning commands are detailed in the below table
zonecreate (zone) create a zone
zoneshow shows defined and effective zones and configurations
zoneadd adds a member to a zone
zoneremove removes a member from a zone
zonedelete delete a zone
cfgcreate (zoneset) create a zoneset configuration
cfgadd adds a zone to a zone configuration
cfgshow display the zoning information
cfgenable enable a zone set
cfgsave saves defined config to all switches in fabric across reboots
cfgremove removes a zone from a zone configuration
cfgdelete deletes a zone from a zone configuration
cfgclear clears all zoning information (must disable the effective config first)
cfgdisable disables the effective zone set
B-series creating a zone commands
Creating zone by WWN zonecreate "zone1", "20:00:00:e0:69:40:07:08 ; 50:06:04:82:b8:90:c1:8d"
Create a zone configuration cfgcreate "test_cfg", "zone1 ; zone2"
saving the zone configuration cfgsave (this will save across reboots)
enable the zone configuration cfgenable "test_cfg"
saving the zone configuration cfgsave
view zoning information zoneshow or cfgshow
B-Series (Cisco) switches uses both web and CLI, the table below displays some but not all the CLI commands, the ones highlighted will be the ones used most often.
EXEC mode commands:
attach connect to a specific linecard
bios BIOS related commands
callhome callhome commands
clear reset functions
clock manage the system clock
config enter configuration mode
debug debug functions
discover discover information
exit exit ffrom the submode
fcping Ping a N_Port
fctrace trace a route for a N_Port
load load system image
no disable debugging functions
reload reboot the switch
setup run the basic setup command facility
show display running system information
system system management commands
test test command
write write the current configuration
zone zoning server commands
CONFIG mode commands:
aaa config aaa
boot configure boot variables
callhome enter the callhome configuration mode
clock configure time and date
fcalias fcalias configuration commands
fcanalyzer configure fabric analyzer
fcc configure FCC congestion control
fcdomain enter the fcdomain configuration mode
fcdroplatency configure switch or network latency
fcflow configure fcflow
fcinterop interop commands
fcns Name server configuration
fcroute configure FC routes
fcs Configure fabric config server
fctimer configure fibre channel timers
fspf configure fspf
interface select an interface to configure
ip configure IP features
no Negate a command or set its default
ntp NTP configuration
power configure power supply
poweroff power off module in switch
qos Configure priority of FC control frames
radius-server configure radius related parameters
role configure roles
snmp-server configure snmp
span enter SPAN configuration mode
ssh configure ssh parameters
switchname configure systems network name
system system config command
trunk configure switch wide trunk protocol
username configure username information
vsan enter the vsan configuration mode
zone zoning configuration commands
zoneset zoneset configuration commands
There are several commands that allow you to navigate through the switch "cd", "copy", "dir", "find", "mkdir", "move", "rmdir" and "tail".
MDS-series creating a zone
create a zone and place it in the vsan # zone name testzone1 vsan 4
add a member (port wwn example) # member pwwn 10:00:00:00:c9:21:40:b8 (port on the host)
add a member (fabric port wwn example) # member fwwn 10:01:10:01:10:ab:cd:ef (port on the switch)
add a member (FCID example - hard zoning) # member fcid 0x7f0000 (24 bit address)
add a member (FC alias example) # member fcalias payroll
MDS-series common commands
display logged in WWN, display vsan information # show flogi database
display the specific vsan logins # show fcns database vsan 4
activatng a zoneset # zoneset activate name zone1 vsan 4
delete a zoneset # clear zone dataabse vsan 4
configure the default zone # zone default-zone permit vsan 4
display zones and zonsets # show zoneset active
# show zoneset
# show zoneset active vsan 4
copy active zone set to the full zone set # zone copy active-zoneset full-zoneset vsan 4
distribute the full zoning database to others switches # zoneset distribute full vsan 4
M-Series (Mcdata) switches uses both web and CLI, the table below displays some but not all the CLI commands.
commadelim Toggle comma-demlimited display mode
config configure settings
login login into CLI with different access rights
maint maintenance settings
perf Performance statistics
reserved reserved for future development
show display attributes
features configure feature settings
ip configure IP settings
logout logout of the CLI
port configure port data
security configure security settings
snmp configure snmp
switch configure switch data
system configure system data
zoning confgiure zoning settings
There are several commands that allow you to navigate through the switch "..", "ctrl-U" and "root" .
M-Series (Mcdata) zoning commands are detailed in the below table
showactive show actively running zoneSet
clearzone clear WWN's in a zone
deletezone remove zone from running config
activezoneset activation of changes
addzone add a new zone to the working area
addwwnmem add a WWN to a zone
showpending show pending zones
renamezone rename a zone
deletewwn delete a WWN from a zone
renamezoneset rename a zone set
Zoning limits
  • 64 zone sets (max)
  • 2000 zones (max)
  • 1024 zones per zone set (max)
  • deafult should all ways be disabled (causes all port to see each other creating ghosts in a FA's login table)

Reset the password on a Dell EqualLogic Storage Array

This is just copy from original article at:

If you really don’t know the password set on the grpadmin but still have physical access to it you can start a recovery procedure to reset the grpadmin account back to the default password: grpadmin.
Important: Because you must power-cycle one group member as part of the password reset procedure, volumes with data stored on that member will be unavailable and active iSCSI connections to those volumes will be lost until the member is restarted. You may want to warn users of any impending offline volumes and iSCSI disconnections before resetting the password.
To temporarily reset the grpadmin account password to the default factory-set password, follow these steps:
1.) On one group member, connect the appropriate serial cable to serial port 0 (the correct cable will be different on different models of the PS Array) on the active control module. The active control module is indicated by the green control module status LED labeled ACT. The status LEDs are located on the controllers sometimes on the left side or next to the serial port on other controllers.
2.) Turn off power to the member (if you have dual power supplies, turn off both power supplies). Volumes with data located on the member will be offline and iSCSI connections to those volumes will be lost until the member is restarted.

3.) If the member has two control modules, after it is shut down, remove the controller that your serial cable is not connected to. This is to ensure that, while you are setting password-recovery mode on one controller, the other controller doesn’t run past us and start the array up.  Controllers just have to be removed a little so they don’t make contact any more to be disabled. (2 cm out is far enough)
4.) Turn on power to the member by turning on all the power supplies.
5.) While the member is restarting, press Ctrl/p when the following message appears on the console: Press Ctrl/p to enter setup mode. This will halt the boot process and allow you to enter commands to the boot monitor.
6.) At the CFE> prompt, enter the following commands, which are case-sensitive and must be typed exactly as shown:
CFE> reload
7.) When the member restarts, the PeerStorage login prompt appears. After a short pause, the following message should appear: WARNING:Password recovery mode… Temporarily resetting grpadmin password.
If you get the previous message, log in the the group using the grpadmin account and its factory-set password, grpadmin:
Login: grpadmin
Password: grpadmin
At this point, you are logged in to the group with read-write permission and can perform any group administration task. At this point, you should set the grpadmin account password to a known value. Use the procedure described in the Modifying Accounts section in the Group Administration manual or use the following command:
> account select grpadmin passwd
Enter New Password: xxxxxxx
Retype password: xxxxxxx
Note: Unless you set the grpadmin account password within five minutes after the password recovery mode message appears, the grpadmin password will revert back to the value it had prior to the password reset procedure (that is, you will no longer be able to log in with the factory-set password).
However, as long as you remain logged in to the grpadmin account, you can set the password to a known value. If the password recovery mode message does not appear, the password reset procedure did not succeed (for example, because you did not enter the CFE commands exactly as shown). In this case, allow the member to completely start up, and then retry the password reset procedure, shutting down the member and following the steps above.
8.) If the member has two control modules, after logging in to the group and setting the grpadmin password, reinsert the second controller,  this restarts the secondary control module and allows it to be used. Within one minute, you should see a console message, indicating that the secondary control module is operational.

FTDI - Virtual COM port for Mac OS X

FTDI - specialists in converting peripherals to Universal Serial Bus (USB).

Virtual COM port (VCP) drivers cause the USB device to appear as an additional COM port available to the PC.  Application software can access the USB device in the same way as it would access a standard COM port.

Tuesday, September 04, 2012

PowerConnect 8024-k : link is up even the switch is power cycled or reloaded

“The below is from the release notes for (listed under the section):

Internal ports are up during most of the switch POST Internal ports were up while switch is booting, this was causing traffic loss in network.

Corrected the initialization of the internal ports. CPLD Code Update is required.

1. Update the CPLD using the command 'dev cpldUpdate'
Console#dev cpldUpdate
2. Power cycle the switch. (Power Cycle from CMC WebUI. Do not run “reload” from the console prompt)