Netapp overview

Netapp storage appliances connect directly to a natwork and have integrated disks.Netapp storage appliances are designed for data storage,use a Data ONTAP operating system.

Netapp supports following protocoles:
1.NFS(Network file Service):
This protocol allows UNIX and PC NFS clients to mount file system to local mount points.
2.CIFS(Common internet file system)
This protocol support windows clients(95,98,2000,NT)
3.FCP(SCSI)
FCP or iSCSI enable a storage device to communicate with one or more hosts such as solaris or windows in a SAN environment.We can configure logical units of storage(LUN) for multi protocol access,for block access or both.
Data ONTAP supports SAN protocols like filer,NearStore,FCP for SCSI and iSCSI for TCP/IP.
4.iSCSI(TCP/IP)
5.DAFS(Direct access file system)
This is designed for local file-sharing environment.Its goals are low latency,high throughput and low overhead.
6.HTTP(Hypertext Transfer Protocol)
7.FTP(File transfer Protocol)

Network Appliance's Data ONTAP provides a arcitecure contains 3 main elements that works together.

• Realtime mechanism for process execution
• WAFL file system containing NVRAM and Snapshots
• RAID Manager

Setting Snapshots in DataONTAP

The Snapshot technology is a key element in implementation of WAFL file system.
Snapshot is a read-only space-efficient,point-in-time image of the data in a volume.
It is only a picture of the file system and doesn't contain actual data.
These are used for backups and error recovery.

Data ONTAP automatically creates and deletes snapshots of data in volumes.
Volumes:
Snapshot for traditional and flexible volumes are stored in special sub directories.These sub directories can be access by both Windows and UNIX clients.maximum of 255 snapshots per volume may be stored at any one time.

Aggregates:
5% of and aggregate is reserved for snapshots of the aggregate.DataONTAP automatically creates snapshots of aggregate to support commands related to the Snapmirror.

Snapshots are taken according to an automatic schedule.We can also can reset it mannually when we configuring the storage appliance.Schedule intervals are weekly,Daily and Hourly.We can perform backups on recently created snapshots with out taking the system offline,because the snapshots are stored independent of the Active File System(AFS).
Before the snapshot is taken we have a file systen tree pointing to data blocks containing content.After the snapshot is taken there is no significant impact on disk space,because file structure take little space and no data blocks need to be copy on disk.But snapshot begins to use space when data is deleted or modified.WAFL writes new data to a new block(D') and change the root structure point to the new block.Meanwhile snapshot still references the original block D.



Allocation of Disk space for flexible volumes

Each aggregate has 5% allocated for snap reserve and 10% allocated for WAFL.Each flexible volume has 20% allocated for snap reserve.The remainder used for client data.The amount of space allocated for snap reserve is adjustable.

Allocation of Disk space for Traditional Volumes

Each aggregate has 10% allocated for WAFL.Each traditional volume has 20% allocated for snap reserve.The remainder used for client data.


The space used for the snap reserve on a volume may expand downward into user space as required by system needs.

Commands use to create and manage Snapshots

If we omit the volume name,the command applies to the root volume.In the snap command the option A is used for aggregates and the option V is used for volumes.Volume is the default.

The snap list command displays a single line of information for each snapshot in a volume.

The "snap sched" command sets the schedule for automatically creating Snapshots and specifies how many of each type will be stored.When the limit is reached,the oldest for each interval is deleted as a new Snapshot is added.
We can also use the FilerView graphical interface to shedule snapshots.

1. Volume-->Snapshot-->Configure
2. Select the Volume
3. Enter the number of snapshots to keep
4. Use the clockfaces to select hours that snapshot will be taken
5. Click Apply

To add snapshots:
Volumes->Snapshots->Add

To view a list of current Snapshots
Volumes->Snapshots->Manage

To delete snapshots manually
Volumes->Snapshots->Manage->check the snapshot->delete

We can enable snapshot in CIFS using the GUI
CIFS->Configure->Option->Show snapshots->set yes

Every volume in the file system contains a special Snapshot sub directory.This allow user to access earlier versions of the file system in case where they need to recover lost or damaged files.

UNIX clients

Snapshot sub-directory apears for NFS client as .snapshot.These directories are usually hidden.
To view the .snapshot directory:

1. logging as root and nosnapdir option is set off: vol option vol0 nosnapdir off
2. To view use ls -a

Windows clients

First configure the file manager to display hidden files,then navigate the root of the CIFS share and look for the directory folder.Snapshot sub-directory appears to CIFS client as ~snapshot.To restore a file from the ~snapshot rename or move original file then copy the file to the directory in which the file is originally existed.

Network settings in DataONTAP

Data ONTAP can resolve host information on a storage appliance using:

1. the /etc/hosts file on the root volume
2. NIS server
3. DNS server

By default the storage first tries resolve hostname locally by searching the /etc/host and /etc/nsswitch file then NIS,then DNS if needed.The /etc/hosts entries: IP address hostname alias(es).

The NIS client service provide information on security related such as hosts,user passwords,user groups and netgroups on a network.

Domain name Service matches domain names to ip addresses and maintain host information ,so we don't need to update the /etc/hosts file.DNS configured using host command.
The /etc/nsswitch.conf file lists the order in which a storage appliance searches for resolution.Also we can set the order using FilerView network->Manage DNS and NIS server.

Routing

Even though Netapp has multiple network interfaces it doesn't act as a router for other hosts.But we can see the currunt routing table using the command netstat -r command.We can add or delete a specific route for a host or a network in the routing table,using the route command.
Default route is defined in the /etc/rc file.We can use rdfile /etc/rc to view content of the file, wrfile /etc/rc to edit the content of the file.
Routed is daemon invoked at the boot time to manage the networking routing tables.

Configuring Network interfaces

Storage appliances support 4 network types of NAS:

• Ethernet 10/100 Base T
• Gigabit ethernet
• FDDI
• ATM

There are 7 network parameters that can be configured for an intreface:

• IP address
• Netmask address
• Media type and speed
• Maximum transmission unit(MTU)
• Flow control
• Up or Down state

On the command line the ifconfig command assigns and address to a network interface and assign these parameters.We can also use filerView Network-->Manage interfaces.

Accessing DataONTAP

To access the storage appliance from client workstation through telnet,type telnet [hostname].hostname is name or ip address of the storage appliance.
To logout of a telnet session press ctrl+d or enter logout telnet.
To enable remote shell services,make rsh.enable on.Set rsh.access value host=adminhost.
To view available commands,at the console prompt enter help or ?.

FilerView is an administration tool available to Netapp storage appliances.This tool enables IT administrator to use a web browser to access graphical user interface for administrator tasks.This allow administrator to set up and control storage remotely without disruption to the business-critical operations.This communicate with the storage with HTML and SNMP protocols.
If we try to open a telnet session in either FilerView or the Command Line Interface directly we can only have one telnet session at a time.

Basic Storage Appliance Configuration

many console commands provide filer system configuration information.

sysconfig -v Display system harware configurations
vol status -r Display volumes and raid group information
sysconfig -r Display volumes and raid group information
sysconfig -c checks configuration levels of hardware

The system configuration is managed via the use of options commands and configuration files:
Option commands
can be entered on console and automatically added to the storage appliance's registry,do not require editing of console files.

Configuration files
/etc/rc,/etc/hosts.equiv,/etc/dgateways,/etc/hosts must be edited to make non-option configuration permanent.

The storage appliance's boot configuration file contains command that are run automatically when the storage is booted./etc/rc is the configuration file of the storage appliance's root volume.The default root volume is /vol/vol0.

The /etc/rc file contains:

• Network interface configuration information.
• Commands to automatically export NFS mounts
• Commands to run at storage appliance startup

When we change the /etc/rc file we have to reboot the storage appliance to test the new configuration.
Persistent configuration information and other data is stored in registry database.There are several backups for these,/etc/registry.lastgood is a copy of the registry as it existed after the last successful boot./etc/registry is edited by DataONTAP shouldn't be manually edited.


Adminstarator users

Administrative console users have the same privilages as root console users.Syslog(/etc/messages)records console logins by username,time of access and node name /address.

useradmin useradd login_name :create new administrator user and a password
useradmin userdel login_name :Delete an administrative user
useradmin userlist :List administrtive users
passwd :Change console administrative user password

The trusted.hosts option can be used to limit telnet and FilerView access to administrative pages.

NFS:
Host name must be entered in the /etc/hosts.equiv file.The setup procedure automatically populate this feature.

CIFS:
Should be a member of the "Domain Administrator"or"Administrators"W@K groups.
edit configuration file by accessing the \\filer\C$ share.

Prepare for Installation

There are three types of software installations:
1.Configuring a new storage appliance.
2.Upgrading Data ONTAP software on existing storage appliance.
3.Re-configuring existing storage


We can re-configure a storage appliance at any time by typing setup at the console.(don't do unless it's a new install)

Configuring a New Storage Appliances

1.Gather information
2.Complete the setup script
3.type reboot to activate the configuration
4.verify the installation

Call center call routing

One of the call center that I was working with is HSBC call center.This a large call center with latest AVAYA technology,giving priority for customer service.
Before going in to details on contact centers let me get an example,a company like where I got my internship.When a customer call from out side he will hear a ring/music/beep then he will receive a welcome massage like "welcome to ABC company.If you know the extension dial now or wait for operator assistance".In there he can either wait or enter the ext he preferred to call.System will route the call to the given end point.This is a simple route pattern to begin.This roting pattern vary with the company complexity and its business.
To understand the call routing further let's take above example.For a PBX system we have to get number and a preallocated extension block from a service provider(SLT,LANKABELL,SUNTEL..).Let's say I got ext from suntel and lankabell:
Suntel - 4 472200 (200-299)
Lankabel- 5 472200 (200-299)
Direct invert dialing is given to last three digits.Take extension 222 as an example.So when customer wants to call to ext 222 he will dial 4472222 directly.Then the system match this to VDN(Vector Directory Number) after placing 1 before the ext.Calls coming to the trunk,we con figure a option in trunk whether to enter a digit or delete a digit.Always changes will be done to the start of the ext.Here we add 1 to the start od DID ext and create a VDN 1222.Each VDN carries a number of it's vector,measurability,COR,COS and other parameters.Measured parameter have 4 options int/ext/none/both.All of them are defining the source of reports.
For external call handling we need E1 cards.Let's take a example of 8 E1 card PBX system,4 E1 cards for the cal

Managing LUN Space

vol options fractional_reserve 0

This command sets the fractional reserve to zero percent, down from the default of 100 percent. Note that fractional reserve only applies to LUNs, not to NAS storage presented via CIFS or NFS.

snap autodelete trigger snap_reserve

This sets the trigger at which Data ONTAP will begin deleting Snapshots. In this case, Snapshots will start getting deleted when the snap reserve for the volume gets nearly full. The current size of the snap reserve can be viewed for a particular volume with the “snap reserve ” command.

snap autodelete defer_delete none

This command instructs Data ONTAP not to exhibit any preference in the types of Snapshots that are deleted. Options for this command include “user_created” (delete user-created Snapshot copies last) or “prefix” (Snapshot copies with a specified prefix string).

snap autodelete target_free_space 10

With this setting in place, Snapshots will be deleted until there is 10% free space in the volume.

snap autodelete on

Now that the Snapshot autodelete options have been configured, this command will actually turn the functionality on.

vol options try_first snap_delete

When a FlexVol runs into an issue with space, this option tells Data ONTAP to first try to delete Snapshots in order to free up space. This command works in conjunction with the next command:

vol autosize on

This enables Data ONTAP to automatically grow the size of a FlexVol if the need arises. This command works hand-in-hand with the previous command; Data ONTAP will first try to delete Snapshots to free up space, then grow the FlexVol according to the autosize configuration options. Between these two options—Snapshot autodelete and volume autogrow—you can reduce the fractional reserve from the default of 100 and still make sure that you don’t run into problems taking Snapshots of your LUNs.

Basics of AVAYA

In my internship I occupied in keels business system ltd,a company in the IT sector of the john keels group.KBSL is a information/Systems Integrator for Enterprises in Sri Lanka.Here I got trained in different sections server,call center,network,loggers,IVR and storage sections.I got chance to deal with real customer problems and come up with solutions.
From this article I'm going to tell the call center solutions mainly AVAYA products handled by KBSL.Let's have some idea about AVAYA products and it's features.
For call centers it's important that we can comunicate free of charge with in the center.If some one calling from out side we have to coordinate with external party(service provider),call will route through public switched terminal network(PSTN).Private Automated Branch Exchange(PABX) plays main role in this process.There may be connection to external parties or to another PBX from a PBX.In john keels holdings we have 5 locations have their own PBXs interconnected all together.There are 3 categories of end points Analog,Digital and IP.Analog and digital end points use Time Devision Multiplexing,IP end points using Internet protocol packet switching.When data and voice in a single network we call it a converge network.AVAYA moving towards voip platform so we have to convince customer to move on to ip platforms.Anlog phone is similar to what we have in our home.Digital phone has some features as call logs,to cater those features it need power,which supplies by the power supply of the PBX.For IP phones we have to install a additional power distribution unit to cater its requirements.

There several card which move in to the PBX system.From the PBX there is connections going to Main Distribution Frame(MDF),called as equipment side.If there are several buildings then it divides in to several Sub Distribution frames(SDF) before it reach end points.CO cards have 8 central office lines.E1 card has 1 E1 lines 30 simultaneous lines,we are getting those on 4 wires TX pair and RX pair.If it is IP we don't need extra card but CLAN.For Analog and Digital we need digital and analog boards(24 port on each).From CLAN we can serve 400 IP phones and media processor can handle 320 packets.
There is trend in customers that they don't want to spend money on their own PBX system,but they prefer to pay a rent if some service provider hosting thr PBX.In this concept all the equipments and lines belong to the service provider,and they can host the PBX in to 2 or 3 companies.They can ask for a rent and can be charge on agent basis.Service provider has the full ownership and management.Here what the can do is whole thing should be in IP platform or they can deploy gateways in customer premises.
In the beginning product now we are talking is come under the name AT&T,but it divided in to sections as AT&T for high end switch providers(SLT) and Luicent for low end providers(Celltel).In 2002 Luicent change it name to AVAYA,which brought over by TPG capital and Silver Lake.They are the only owners in AVAYA,there are no shares in the market.As in IP platform concern CISCO is competing AVAYA.
Avaya communication manager is thousands of C codes built on Linux platforms.Avaya CM5 is release 5 on Linux,but Cisco call manager 5 is the second release on Linux.This fact sounds AVAYA more reliable to me.
To connect to the PSTN we use CO(central office)lines and E1 lines.E1 uses two signaling protocols ISDN and R2 signaling.There is a limitation in R2 signaling,it doesn't allow name passing transparency,but ISDN has allow it.This is a useful feature to serve customers in call centers,agent can welcome the customer from his name.To connect two PBXs together we use QSIG signaling.

Let's consider some basic features in AVAYA.

Auto attendant:
When you call to a company you may have hear a announcement which says if know the extension you can dial the extension or wait until operator connects you.Auto attendant is this if know the extension we don't need a operator.

Direct Invert Dialing(DID):
Service provider has given us a E1 line which can cater 30 channels simultaneously.But service provider has allocated extension blocks that we can use for our company.Let's say we got 300-399 block.So in DID we can call directly to a person using his extension at the end.
for operator :2317000
Directly to 350:2317350

Transferring:
We can transfer calls to other places,even after we pick the phone

Conferencing:
We can get multiple parties to join to the same discussion on telephone.

Call Pick up:
We can create a group,and we can pick up call from any where within the group.It is need not be the original phone.

Call waiting:
When I'm in a call,if some one calling me that call appears in the phone.If I want to answer that 2nd call I can put 1st person in to on hold.

Call Coverage:
This feature send received call to the next person if I'm busy.It will ring mt extension some time(as we planned) and then will ring the next place.Anyhow the call will get served.