Xen318

Tuesday, January 24, 2017

Below is an alternate method that I have used to remove disks owned by control domain

Obtain the UUID of the VM in question

<UUID of VM> = 26708987-c6b2-3243-c49c-db20a96b15a8

From the command line interface run the following command:

xe vbd-list vm-uuid=26708987-c6b2-3243-c49c-db20a96b15a8
uuid ( RO) : 81ae5475-02fd-ba46-68f6-4a170102641a
vm-uuid ( RO): 26708987-c6b2-3243-c49c-db20a96b15a8
vm-name-label ( RO): FvWebProxy01
vdi-uuid ( RO): <not in database>
empty ( RO): true
device ( RO): xvdd

uuid ( RO) : 974dc129-48bf-eac2-ab6c-467ef0dfd620
vm-uuid ( RO): 26708987-c6b2-3243-c49c-db20a96b15a8
vm-name-label ( RO): FvWebProxy01
vdi-uuid ( RO): 8d673a64-26a2-4e8e-8c8d-0cd4efcf2520
empty ( RO): false
device ( RO): xvda

and then execute the following command. NOTE: I chose vdi-uuid 8d673a64 because the other VDI is listed as not in the database

xe vbd-list vdi-uuid=8d673a64-26a2-4e8e-8c8d-0cd4efcf2520
uuid ( RO) : 64cd3f2e-66c4-ae3f-7f53-d83d97d2601f
vm-uuid ( RO): 70ad4283-6d3e-47c6-9c3c-070f586f43c2
vm-name-label ( RO): Control domain on host: FsXENSVR152
vdi-uuid ( RO): 8d673a64-26a2-4e8e-8c8d-0cd4efcf2520
empty ( RO): false
device ( RO): sm/backend/2710d6e3-fb6b-0cdf-0230-845f87620eab/8d673a64-26a2-4e8e-8c8d-0cd4efcf2520

uuid ( RO) : 974dc129-48bf-eac2-ab6c-467ef0dfd620
vm-uuid ( RO): 26708987-c6b2-3243-c49c-db20a96b15a8
vm-name-label ( RO): FvWebProxy01
vdi-uuid ( RO): 8d673a64-26a2-4e8e-8c8d-0cd4efcf2520
empty ( RO): false
device ( RO): xvda

and then run the following command. NOTE: I chose UUID 64cd3f2 because as you can see the vm-name-label is Control domain on host

xe vbd-unplug uuid=64cd3f2e-66c4-ae3f-7f53-d83d97d2601f
The device is not currently attached
device: 64cd3f2e-66c4-ae3f-7f53-d83d97d2601f

xe vbd-destroy uuid=64cd3f2e-66c4-ae3f-7f53-d83d97d2601f

The VM disks that were owned by the control domain should now be gone.

Monday, January 23, 2017

VM disks Owned by the Control Domain

You tried to migrate a VM, move a disk, or take a snapshot, and you look on your SR to find that your VM’s disk is owned by “the control domain”.

1. Why does this happen?

Basically it boils down to disk operations on/from a VM failing. Operations such as move, copy, snapshot, export, etc.

2. How do I get around it?

One answer is to reboot.

Another way is to find the link between your virtual disk and DOM0 (the control domain) from your stand-alone XenServer (or primary server if you have a pool).

Use list_domains to get the UUID of DOM0 (the control domain):

The control domain UUID is 09dffafe-5bec-430d-bc80-6ddb2313beff

Now we have to find the VBD(s) that DOM0 (the control domain) owns:

xe vbd-list vm-uuid=<DOM0 UUID, such as 09dffafe-5bec-430d-bc80-6ddb2313beff id>

This will show information about any Virtual Block Device (VBD) that DOM0 (the control domain) may be hanging onto. What we are interested in is the UUID of the VBD(s).

Grab the VBD’s UUID and execute:

xe vbd-unplug uuid=<UUID of the VBD being held by DOM0>

Finally, run:

xe vbd-destroy uuid=<UUID of the VBD being held by DOM0>

And there – rescan your storage repository and your VDI (virtual disk interface) should be free for your use.

Switch Commands

Dell M8024-k switch

Enable SSH on switch

Connect to switch via CLI

Module A1(config)#crypto key generate dsa

Do you want to overwrite the existing DSA keys? [Y | N] :y

DSA key generation started, this may take a few

minutes..................................................................................................................................

.......................................................
DSA key generation complete.

Module A1(config)#crypto key generate rsa

Do you want to overwrite the existing RSA keys? [Y | N] :y

RSA key generation started, this may take a few minutes....................
RSA key generation complete.

Module A1(config)#ip ssh server

Module A1(config)#exit

Module A1#exit

Module A1>en
Password:***********

Module A1#show ip ssh

SSH Server enabled. Port: 22
Protocol Levels: Versions 1 and 2.
SSH Connections Currently in Use: ............. 0
Maximum number of SSH Sessions Allowed: ....... 5
SSH Session Timeout: .......................... 600
RSA key was generated.
DSA key was generated.
SSH Public Key Authentication is disabled.

Active Incoming Sessions.

Ip Address User Name Idle Time Session Time
--------------- --------------- ------------ ------------

Module A1#exit

Module A1>exit

=====================
Disable Telnet
=====================

config
ip telnet server disable
exit

test a telnet connection to see if it fails

========================================================================

Ran the following command from the command line interface :

config t
line vty 0 4
transport input ssh

line 5 15
transport input ssh

copy run start

I tested a telnet connection and it failed. SSH connection worked successfully.

========================================================================

============
Enable HTTPS
============

Module A2(config)#crypto certificate 1 generate

Module A2(config-crypto-cert)#?

common-name Specifies the common name.
country Specifies the country name.
do Run Privileged Exec mode commands.
duration Specifies number of days a self-signed certi fication
would be valid. If unspecified defaults to 3 65 day.
email Specifies the contact email address.
exit To exit from the mode.
key-generate Regenerate SSL RSA key.
location Specifies the location or city name.
organization-name Specifies the organization name
organization-unit Specifies the organization internal unit
show Show configured settings and operational sta tus.
state Specifies the state or province name.

Module A2(config-crypto-cert)#key-generate ?

<cr> Press enter to execute the command.
<length> Specifies the length of the SSL's RSA key. I f
unspecified, length defaults to 1024.

Module A2(config-crypto-cert)#key-generate

Module A2(config-crypto-cert)#exit

Certification Generation Successful..

Module A2(config)#ip http secure-certificate 1

Module A2(config)#ip http secure-server

Module A2(config)#exit

Module A2#show ip http server secure status

HTTPS Server is Enabled. Port : 443
DH Key exchange enabled.
Certificate 1 is active.
Issued by: self-signed
Valid from Mar 8 05:11:14 2006 GMTMar 8 05:11:14 2007 GMT0.0.0.0 to Mar 8 05:11:14 2007 GMT0.0.0.0
Subject: /CN=0.0.0.0
Fingerprint: DF1027F336CC450ED2AC1C740DF24921

Module A2#show ip telnet

Telnet Server is Disabled. Port : 23

Module A2#show ip http server status

HTTP Server is Disabled. Port : 80

Monday, May 9, 2016

XenServer Host Crashed - What to do?

Good info

http://www.gregorystrike.com/2012/04/16/xenserver-host-failed-what-now/

Courtesy of: http://citrixtechs.com/blog/help-my-citrix-xenserver-poolmaster-is-down-2/

It’s 3 O’Clock in the morning, do you know where your Xenserver Poolmaster is? Your client calls you frantic, and you start a GoToMeeting to see what’s wrong. If it’s down, this could have been the result of a few issues. Maybe there was a network glitch which resulted in the Citrix XenServer Poolmaster fencing itself from the rest of the farm. This can also result during a power outage, or other catastrophic failure. This is the normal defense mechanism built into Xenserver, and in the consulting world we see this type of scenario often. You can’t simply reboot the Poolmaster to bring it online. Restarting the toolstack will do you no good. There is a complex process that must be followed, so let’s discuss it –

If you’ve tried to connect to the pool from the Xencenter console, and it failed – your Poolmaster may be down. Verify this by dropping to a command prompt and issue a command like “Xe host-list” to see if you get a coherent response. If you get an error message like ““Cannot perform operation as the host is running in emergency mode” – then your Poolmaster is almost certainly down.

How do I get the Poolmaster back up?

This is easier said than done. First you’ve got to promote another server in the farm to become the Poolmaster, so that it can take over pool operations. From that servers CLI, type the command, “xe pool-emergency-transition-to-master” which will transition it to be the new Poolmaster. If the command runs successfully, you can recover the other pool servers by issuing the command, “xe pool-recover-slaves”. Now if pool management is working again, you should be able to successfully run the “xe host-list” command and get a valid response.

Now that the pool is back online, how do I fix the failed poolmaster?

1). First you have to figure out which server in the environment has failed. To do this, you’ll want to run the command, “xe host-list params=uuid,name-label,host-metrics-live”. Any servers that come back with “host-metrics-live = false” have failed. Take note of the UUID of any failed servers

2). Second, you must determine which VM’s were running on that failed server. You can do this by running the command, “xe vm-list is-control-domain=false resident-on=UUID_of_failed_server”. Once you’ve determined which VM’s were running, you need to reset their power state in order to get them to move onto another server. To do this, run the command, “xe vm-reset-powerstate resident-on=UUID_of_failed_server –force –multiple”. You should see the VM’s in question now show up as halted in the Xencenter console. Restart each of the VM’s, and they should now boot up onto surviving pool member servers.

For more information on various issues you can run into during this process, check out the official Citrix whitepaper here:

http://support.citrix.com/servlet/KbServlet/download/17140-102-18520/XenServer%20System%20Recovery%20Guide.pdf

What are some root causes as to why my Xenserver Poolmaster may have been down?

The usually suspects include your network, because if the poolmaster loses connectivity to some of the other Xenserver hosts in your environment, it could fence itself and go offline as a built in defense mechanism. Poolmaster fencing is a typical issue that can occur if there are network issues in your environment, so check with the network team before you pass go.

Monday, July 6, 2015

XenServer Host Failure

XenServer Host Failed

Find the UUID of failed server
xe host-list

Find out which VMs were running on failed server
xe vm-list resident-on= <UUID of XenServer>

Tell pool that the VMs are powered off
xe vm-reset-powerstate resident-on= <UUID of XenServer> --force --multiple

This will reset the power for the VMs that were running on this XenServer so that we can now see them in XenCenter

Friday, April 24, 2015

Steps to address a hung XenServer virtual machine:

Find the UUID of the hung virtual machines. This is done from the command line of the XenServer hosting the problem virtual machine. The command to execute is xe vm-list. Another way to find the UUID of the virtual machine is to click the ‘General’ tab of the virtual machine in XenCenter.

Once you have the UUID you need to find the domain ID of the hung virtual machine. This is done by executing the command list_domains from the XenServer hosting the problem virtual machine. You will need to match the UUID with domain ID number. The output of this command will look like this:

id | uuid | state

0 | 2fe455fe-3185-4abc-bff6-a3e9a04680b0 | R

47 | 267227f3-a59e-dafe-b183-82210cf51ec4 | B

59 | 298817fb-8a3e-7501-11e0-045a8aa860ff | B

(i.e. UUID 267227f3-a59e-dafe-b183-82210cf51ec4 has a domain ID of 47)

To free the virtual machine we need to execute destroy_domain command on the domain ID. This is done by executing the command:

/opt/xensource/debug/destroy_domain –domid 47

Note: 47 is the domain ID

If the Host reports the vm in a halted state after running xe vm-list, try to reset the power.

To reset the power state run the following command:

xe vm-reset-powerstate vm=VM NAME force=true where VM Name is the server name.

xe vm-shutdown vm=VMNAME force=true where VM NAME is the server name.

Once the VM is shutdown, restart on another XenServer

xe vm-start vm=VMNAME

Sometime running commands using the XenServer command line will yield you more information about a problem that otherwise XenCenter may not reveal to you.

For example: If the VM is having issues starting; executing the command xe vm-start name-label= <Name of VM> will likely get more information about what may be causing the issue.

Also, sometimes a server will not report to its host after being migrated. It is either stuck in powering off (staying in yellow) or powering on. Run this command on from the pool master for that pool.

xe-toolstack-restart

The VM should show back up. If not close out of XenCenter and reopen.

How to Setup XenServer 6.x to Auto-Start Virtual Machines

Setting the XenServer to allow Auto-Start

Gather the UUID’s of the pools you wish to auto-start.

To get the list of the pool’s on your XenServer type “xe pool-list”

Copy the UUID of the pool. If you have just one server, it will still have a pool UUID as noted in the following screenshot:

Then type the following command to set the pool or server to allow auto-start:
xe pool-param-set uuid=UUID other-config:auto_poweron=true

Note: Replacing UUID with the UUID of the XenServer or pool.

Setting the Virtual Machines to Auto-Start

Gather the UUID’s of the Virtual Machine you want to auto-start by typing:

xe vm-list

Note: This generates a list of Virtual Machines in your pool or server and their associated UUID’s.

Copy the UUID of the Virtual Machines you want to auto-start, and type the following command for each Virtual Machine to auto-start:

xe vm-param-set uuid=UUID other-config:auto_poweron=true

Note: Replace UUID with the UUID of the Virtual Machine to auto-start.

Steps to install NIC drivers on XenServer

Steps to install NIC drivers on XenServers

Check NIC driver version by running ethtool -i eth0

I created a directory in the tmp directory called iso. It does not have to be called iso this is just what I chose. I performed this using WinSCP

[root@fsxensvr14 ~]# cd /tmp/iso

Copy the NIC drivers to this new directory and then perform an ls to view the files in the directory

[root@fsxensvr14 iso]# ls

bnx2x-1.74.22.tar.gz bnx2x.iso bnx2x.iso.md5 bnx2x.metadata.md5

Mount the iso using the following command. You are mounting the iso to the /tmp/iso directory that you created earlier

[root@fsxensvr14 iso]# mount bnx2x.iso /tmp/iso -o loop,ro

Change directories to the /tmp/iso directory

[root@fsxensvr14 iso]# cd /tmp/iso

Perform an ls to view the files in the directory

[root@fsxensvr14 iso]# ls

bnx2x-modules-kdump-2.6.32.43-0.4.1.xs1.6.10.784.170772-1.74.22-1.i386.rpm

bnx2x-modules-xen-2.6.32.43-0.4.1.xs1.6.10.784.170772-1.74.22-1.i386.rpm

install

install.sh

XS-PACKAGES

XS-REPOSITORY

Execute install.sh by running the following command

[root@fsxensvr14 iso]# ./install.sh

Installing 'Broadcom bnx2x driver'...

Preparing... ########################################### [100%]

1:bnx2x-modules-xen-2.6.3########################################### [ 50%]

2:bnx2x-modules-kdump-2.6########################################### [100%]

Pack installation successful.

Change directories to root by running the following command

[root@fsxensvr14 iso]# cd /

Unmount the /tmp/iso directory by running the following command

[root@fsxensvr14 /]# umount /tmp/iso

Clean UP !! Delete the files that you copied over to perform the installation.

Wednesday, February 25, 2015

Check the performance of your storage repository

Ref: http://support.citrix.com/article/CTX121634

[root@FsXENSVR109 ~]# ll /dev/disk/by-id/ | grep <SCSI ID> NOTE: SCSI ID can be found on the 'General' tab of your SR in XenCenter

The output of this command will be something like the following:

lrwxrwxrwx 1 root root 9 Feb 12 19:16 scsi-36000d3100087d3000000000000000005 -> ../../sdb

Once you have this information you can execute the following command

[root@FsXENSVR109 ~]# hdparm -t /dev/sdb

/dev/sdb:
Timing buffered disk reads: 248 MB in 3.06 seconds = 81.08 MB/sec
[root@FsXENSVR109 ~]# hdparm -t /dev/sdb

Friday, January 30, 2015

XenServer MultiPath Info

Useful commands discovered and used along the way.

Check iSCSI sessions

iscsiadm -m session

Ping storage from a particular NIC IP address

ping -I xenbr8 192.168.190.10

Note: You may need to use this command to figure out where to ping from
brctl show
Show info on virtual switches

Rescan iscsi sessions

iscsiadm -m session -r 1 --rescan

Show all records in discovery database and show the targets that
were discovered from each record:
./iscsiadm -m discovery -P 1

Display session statistics:
./iscsiadm -m session -r 1 --stats

Display running sessions:
./iscsiadm -m session -P 1

Restart iscsi service
service open-iscsi restart

Check iscsi service status
service open-iscsi status

To get information about the running sessions: including the session and
device state, session ids (sid) for session mode, and some of the
negotiated parameters, run:
iscsiadm -m session -P 2

To get a Host view of the session there is the host mode.
iscsiadm -m host

Log into iSCSI targets
iscsiadm -m node --login

To log into an individual iSCSI target use:
iscsiadm -m node -l -T iqn.2001-05.com.equallogic:83bcb3401-16e0002fd0a46f3d-rhel5-test -p 172.23.10.240:3260

TFTP - cheat sheet

Here is a quick reference on how to backup/restore switch configurations...

A free TFTP server is available for download from Solarwinds website

To copy a switch configuration to a TFTP server run the following command:

copy running-configuration tftp://TFTP-IP/filename.txt

To copy a switch configuration from a TFTP server to switch run the following command:

copy TFTP://TFTP-IP/filename.txt startup-configuration

Then type:
reload

Friday, October 24, 2014

vDisk owned by Control Domain

VM disks becoming “owned by the Control Domain”.

You know: you tried to migrate a VM, move a disk, or take a snapshot and POW: you look on your SR to find that your VM’s disk is owned by “the control domain”.

1. Why does this happen?

Basically it boils down to disk operations on/from a VM failing. Operations such as move, copy, snapshot, export, etc.

2. How do I get around it?

One answer is to reboot.

Another way is to find the link between your virtual disk and DOM0 (the control domain) from your stand-alone XenServer (or primary server if you have a pool).

Use list_domains to get the UUID of DOM0 (the control domain):

The control domain UUID is 09dffafe-5bec-430d-bc80-6ddb2313beff

Now we have to find the VBD(s) that DOM0 (the control domain) owns:

xe vbd-list vm-uuid=<DOM0 UUID, such as 09dffafe-5bec-430d-bc80-6ddb2313beff id>

This will show information about any Virtual Block Device (VBD) that DOM0 (the control domain) may be hanging onto. What we are interested in is the UUID of the VBD(s).

Grab the VBD’s UUID and execute:

xe vbd-unplug uuid=<UUID of the VBD being held by DOM0>

Finally, run:

xe vbd-destroy uuid=<UUID of the VBD being held by DOM0>

And there – rescan your storage repository and your VDI (virtual disk interface) should be free for your use.

Wednesday, July 30, 2014

Prevent users from auto-forwarding their email to an external domain

Monday, July 28, 2014

XenApp 6.x terminology mapped to XenApp 7.x

XenApp 6 Instead of…	XenApp 7 Think of…
Independent Management Architecture (IMA)	FlexCast Management Architecture (FMA)
Farm	Delivery Site
Worker Group	Session Machine Catalog Delivery Group
Worker	Virtual Delivery Agent Server OS Machine Desktop OS Machine
Zone and Data Collector	Delivery Controller
Delivery Services Console	Citrix Studio and Citrix Director
Publishing applications	Delivering applications
Data store	Database
Load Evaluator	Load Management Policy
Administrator	Delegated Administrator Role Scope

Send mail via telnet

1. Telnet mail.domain.com 25 (obviously replace mail.domain.com with whichever mail server you want to use.)

2. helo your domain name

3. mail from:your email address

4. rcpt to:destination address

5. data

6. Type your message

7. . (type a period and hit enter)

Configure users for internal mail routing only

You should be able to use Transport Rules to do that. Make sure those groups are Distribution Groups (they can eventually be hidden from Address Lists).

To forbid sending E-mails outside of Exchange, create a rule:

if sender is member of group2
and message is sent outside the organization
then drop the message
and send NDR with status code (choose code and message)

To forbid receiving E-mails from the Internet:

either use the same principle (if user is member of group2 and sender is outside the organization, drop with a custom message
or in the delivery options for those users, only allow messages from authenticated users
you can make exceptions, for instance if you have custom applications sending messages directly to Exchange

For group3, then

create a rule that forbids sending to member of a distribution list when sender is member of group3
and send NDR etc

Link:

http://social.technet.microsoft.com/Forums/en-US/aeece703-a5b9-40ff-9ec1-e2977f7d6a56/how-to-configure-users-for-internal-mail-routing-only

Thursday, July 24, 2014

vLAN Tagged/Untagged

Assigning Ports to vLANs

Before enabling vLANs for the switch, you must first assign each port to the vLAN groups in which it will participate. By default, all ports are assigned to vLAN 1 as untagged ports. You should add a tagged port (a port attached to a vLAN-aware device) if you want it to carry traffic for one or more vLANs and the device at the other end of the link also supports vLANs. Assign the port at the other end of the link to the same vLANs. However, if you want a port on this switch to participate in one or more vLANs and the device at the other end of the link does not support vLANs, you must add an untagged port (a port attached to a vLAN-unaware device).
Port-based vLANs are tied to specific ports. The switch's forwarding determination is based on the destination MAC address and its associated port. Therefore, to make valid forwarding and flooding decisions, the switch learns the relationship of the MAC address to its related port (and to the vLAN) at run-time.

Think of it this way - untagged port is when you have an end device that doesn't know what tagging is, but you still need to assign it to a particular vLAN. Basically, you're telling the switch that "All traffic in from this port that doesn't explicitly have a tag will get tagged with this vLAN ID"

If your switches understand vLANs, then you would tag the ports between them. You tell the switch that traffic with these vLAN tags is allowed to pass.

For inter vLAN routing you need to either go through your router, or enable routing in your switches. You need to explicitly allow this, otherwise you can't reach one vLAN from another

"Trunk" ports are those between switches or a switch and a device like an access point or firewall, where you could need more than one vLAN to pass.

Cisco Router Interface Status

The first line of the show interface command is the most important one. The first parameter refers to the physical layer, therefore in this case FastEthernet 0 is up and operating. The second part of the line refers to the Data Link Layer; therefore here line protocol is up means that we have layer 2 connectivity as well.

There are four possible outputs that you may come across:

FastEthernet0 is up, line protocol is up: Both the Physical and Data Link layers on the interface are functioning correctly.
FastEthernet0 is down, line protocol is down: This output indicates a physical interface problem. For example, the cable on this interface or on the remote interface is disconnected.
FastEthernet0 is up, line protocol is down: In this case, Physical layer is operational. The line protocol being down indicates a clocking or framing problem. Probable reasons for this are encapsulation and clock rate mismatches.
Ethernet0 is administratively down, line protocol is down: This output indicates that a local interface has been manually shut down using the shutdown command.

===============================================================================================================
#1: The "?"

It may seem entirely too obvious that you should know how to type ? to ask for help when using the Cisco IOS. However, the Cisco IOS is completely different from other operating systems when it comes to using the question mark (help key). As the IOS is a command-line operating system with thousands of possible commands and parameters, using the ? can save your day.

You can use the command in many ways. First, use it when you don't know what command to type. For example, type ? at the command line for a list of all possible commands. You can also use ? when don't know what a command's next parameter should be. For example, you might type show ip ? If the router requires no other parameters for the command, the router will offer CR as the only option. Finally, use ? to see all commands that start with a particular letter. For example, show c? will return a list of commands that start with the letter c.

#2: show running-configuration

The show running-config command shows the router, switch, or firewall's current configuration. The running-configuration is the config that is in the router's memory. You change this config when you makes changes to the router. Keep in mind that that config is not saved until you do a copy running-configuration startup-configuration. This command can be abbreviated sh run.

#3: copy running-configuration startup-configuration

This command will save the configuration that is currently being modified (in RAM), also known as the running-configuration, to the nonvolatile RAM (NVRAM). If the power is lost, the NVRAM will preserve this configuration. In other words, if you edit the router's configuration, don't use this command and reboot the router--those changes will be lost. This command can be abbreviated copy run start. The copy command can also be used to copy the running or startup configuration from the router to a TFTP server in case something happens to the router.

#4: show interface

The show interface command displays the status of the router's interfaces. Among other things, this output provides the following:

Interface status (up/down)
Protocol status on the interface<
Utilization
Errors
MTU
This command is essential for troubleshooting a router or switch. It can also be used by specifying a certain interface, like shint fa0/0.

#5: show ip interface

Even more popular than show interface are show ip interface and show ip interface brief. The show ip interface command provides tons of useful information about the configuration and status of the IP protocol and its services, on all interfaces. The show ip interface brief command provides a quick status of the interfaces on the router, including their IP address, Layer 2 status, and Layer 3 status.

#6: config terminal, enable, interface, and router

Cisco routers have different modes where only certain things can be shown or certain things can be changed. Being able to move between these modes is critical to successfully configuring the router.

For example, when logging in, you start off at the user mode (where the prompt looks like >). From there, you type enable to move to privileged mode (where the prompt looks like #). In privileged mode, you can show anything but not make changes. Next, type config terminal (or config t) to go to global configuration mode (where the prompt looks like router(config)# ). From here, you can change global parameters. To change a parameter on an interface (like the IP address), go to interface configuration mode with the interface command (where the prompt looks like router(config-if)#). Also from the global configuration mode, you can go into router configuration using the router {protocol} command. To exit from a mode, type exit.

#7: no shutdown

The no shutdown command enables an interface (brings it up). This command must be used in interface configuration mode. It is useful for new interfaces and for troubleshooting. When you're having trouble with an interface, you may want to try a shut and no shut. Of course, to bring the interface down, reverse the command and just say shutdown. This command can be abbreviated no shut.

#8: show ip route

The show ip route command is used to show the router's routing table. This is the list of all networks that the router can reach, their metric (the router's preference for them), and how to get there. This command can be abbreviated shipro and can have parameters after it, like shiproospf for all OSPF routers. To clear the routing table of all routes, you do clear ip route *. To clear it of just one route, do clear ip route 1.1.1.1 for clearing out that particular network.

#9: show version

The show version command gives you the router's configuration register (essentially, the router's firmware settings for booting up), the last time the router was booted, the version of the IOS, the name of the IOS file, the model of the router, and the router's amount of RAM and Flash. This command can be abbreviated shver.

#10: debug

The debug command has many options and does not work by itself. It provides detailed debugging output on a certain application, protocol, or service. For example, debug ip route will tell you every time a router is added to or removed from the router.

Cisco Router ACL

Add an ACL to an existing extended access list
http://sysadminnotebook.blogspot.com/2011/07/creating-and-editing-cisco-extended.html

show ip access-list

show ip access-list <name of access list>

Example:
config t
ip access-list extended branch_repeater
70 permit ip 192.168.210.0 0.0.0.255 10.0.0.0 0.0.255.255

EqualLogic Delegated Space

Best way to get a good calculation as to how much delegated space to reserve is to add up the amount of space displayed in the location <Replication button > Outbound Replicas>

Once this amount of space is added up then you can determine if you have too much delegated space configured.

So for example if I add up my volume replica reserve and it totals 45Tb and I currently have 48Tb configured I can proably split the difference and reduce the amount of delegated space by 1.5Tb.

Also, it is recommended to keep a minimum of 10% of disk space free to allow for background operations.