System Mailbox in exchange server 2003:

This article gives you the functionality of the built in system mailbox that present in the mailbox store. Every private information store in Exchange Server 2003, has 3 system mailbox by default.

The following are the three different system mailboxes are:

•SystemMailbox{GUID}
•System Attendant Mailbox
•SMTP Mailbox

System Mailbox {GUID}:

•Contains two parts to each System mailbox – the mailbox itself with its content in the corresponding information store and an associated directory object located in MESO (Microsoft Exchange System Object) folder in AD.
•GUID is related to the objectGUID i.e., to the system mailbox. The objectGUID of the mailbox store with which the system mailbox is associated.
•Whenever we mount the store, it checks for the availability of the systemmailbox{GUID}. If not it looks in the MESO directory for the same.
•Each MDB has its own GUID associated with a particular instance of SystemMailbox{guid}.
•Faulty functioning SystemMailbox{guid} then, there’s a very good chance EXOLEDB event sinks will not function.
•It will occupy some reasonable amt of space for storing the schema definitions.

System Attendant Mailbox:

•Each Exchange 200x server has one (and hopefully only one) System Attendant mailbox
•The System Attendant Mailbox contains the folder SpecialPrivateFolderForFreeBusyStorage, for Free/Busy information for Microsoft Outlook and CDO Applications (Collaboration Data Objects) which will be temporarily stored in MSExchangeFBPublish.
•The System Attendant Mailbox will also be used to send and receive Exchange monitoring messages for the Link Monitoring Service. You can find this function in the Exchange System Manager under Tools – Monitoring and Status.
•System Attendant mailbox is also required to be available during mailbox moves. For instance, if you have the mailbox store containing the System Attendant mailbox dismounted during a mailbox move, the move will fail.
•There are two parts to make up the complete System Attendant mailbox: a directory object and a mailbox object.
•Faulty system attendant mailbox, results in OWA-generated Free/Busy information not getting updated and also mailbox moves fail.

SMTP Mailbox

•The SMTP mailbox will be generated when the private information store is created and mounted.
•SMTP (servername-{guid}) mailbox is used by the mail transport of Exchange 200x as a temporary holding place for various messages as they pass through the system. In other words, every private mailbox store contains an SMTP mailbox to store temporary messages.
•For eg, The folders MTS-IN and MTS-OUT are used by Exchange Deployment Kit (EDK) connectors to transfer messages between the MTA (Microsoft Exchange Transport Agent) and the Exchange Server information store (store.exe). They are also used for X400 connectors, Exchange site connectors, and fax connectors.
•Faulty SMTP mailbox, results in failure in delivery into the store

Logging into system mailbox:

Logging into the system mailbox is not recommended, but still we can open the mailbox using the MFCMAPI.

Please revert if you have any questions.

Thanks

Logu

logu_microsoft@hotmail.com
91-9841499143

Microsoft Exchange System Attendant:

This article explains the characteristic features of the Microsoft exchange system attendant services. The Microsoft Exchange System Attendant service is primarily a collection of subcomponents that work together to proxy Active Directory requests and to regulate internal Exchange Server functions.

1.It is exchange related services. It is critical for exchange server’s performance and many exchange related services will not work.
2.You cannot mount the database unless the exchange system attendant service is running.
3.It facilitates AD communications to enforce the retention policies and mailbox quotas.
4.Main executable file is the MAD.EXE, located in Program Files\Exchsrvr\Bin folder and most of the subcomponents exist as .DLL files.

The following are the components of the System Attendant services.

DSACCESS Component:

1.DSACCESS.dll is used to prevent exchange server from flooding your exchange server with excessive requests.
2. In detail, When exchange server component such as exchange store or SMTP Transport engine needs to get the receipient information from AD, the query is routed through the DSACCESS component. Generally it acts as a proxy for these AD request. The recent request are stored in the cache to avoid the repetitive queries.

DSProxy Component:

1.DSProxy.dll acts as a proxy for AD queries coming from outlook clients.
2.In detail, when client running outlook 2000 or later, refers the GC for processing the AD query (such as a request to retrieve the GAL) in direct. Whereas the client older the outlook client 2000, will acts as a true proxy for communicating the GC, so DSProxy performs he operation on behalf of the client.
3.DSACCESS performs differently, DSACCESS proxies AD request coming from the other exchange component.

RUS – Recipeint Update Service:

1.Abv_dg.DLL is the core file for the RUS.
2.It is used for applying recipient policies to mail-enabled user objects.

Mailbox Manager Component:

The Mailbox Manager's job is to enforce policies that help to control the size of an information store, including mailbox quotas and message retention policies.

Server Monitor Component:

1.It is primarily used to keep exchange server’s link state information up to date.
2.The link state information is used to calculate the optimal path to various destinations within the exchange organization. Metrics like costs, availability and hop counts are taken into account.
3.It is responsible for monitoring server resources using WMI Windows Management Instrumentation.
4.It is also responsible for managing message tracking logs (if the message tracking is enabled).

Offline Address Book Generator:

1.The idea behind OAB generator (OABgen.dll) is for mobile users to access the address book, even is the users are offline.
2.So the offline users rely on the OAB instead of GAL.
3.The OABgen.dll file is stored in an Exchange public folder subfolder called Offline Address Book. This folder contains two subfolder: OAB Version2 and OAB Version 3a.

Free/busy Component:

1.The free/busy (madfb.dll) component is responsible for publishing the free busy information.
2.In detail, free busy information of other attendee is required for scheduling meeting. So the source user needs the free busy data of the target attendee’s calendar. Since user don’t generally have access to other user’s mailbox. Like OAB, the free/busy(madfb.dll) component is stored in a subfolder of the system public folder named SCHEDULE + FREE BUSY.
3.When a user creates an appointment or meeting, the exchange store sends the corresponding free/busy information to the exchange system attendant mailbox. The madfb.dll extracts the free busy data from the message and publishes it in the SCHEDULE + FREE BUSY folder.

Metabase Update Service:

1.Metabase Update Service (ds2mb.dll) is closely related to the IIS.
2.IIS metabase is the core file for IIS. Given that, exchange is dependent on IIS, exchange is also dependent on the IIS metabase.
3.IIS metabase exists in the form of an XML file named Metabase.xml, also stores as binary file called Metabase.bin (located in System root\system32\inetsrv) and the corresponding schema file called MBSchema.xml.
4.Some Exchange configuration information related to SMTP Virtual servers, the HTTP configuration of OWA and few others are stored in AD, but are needed by IIS. This is where the Metabase Update Service comes into play. This service replicates protocol related exchange server configuration information from the AD to the IIS metabase.

Hope the above is informative. Please ping me if you have any questions.

Thanks

Logu

logu_microsft@hotmail.com
91-9841499143

Finding the mailboxes homed in particular mailbox store:

This article explains the different type of methods to find the mailbox homed in particular mailbox store. In simple words, the methods used for querying the mailbox based on the mailbox store information.
When you try to delete a mailbox store from a server that is running Exchange 2000 or Exchange 2003, you may receive the following error message:
“One or more users currently use this mailbox store. These users must be moved to a different mailbox store or be mail disabled before deleting this store.
ID no: c1034a7f
Exchange System Manager”.

In that, we need to find the mailboxes that are homed in that particular mailbox store. The following are the different types of method to find that respective mailboxes.

Method 1: Use the LDP tool (Ldp.exe) to browse for mailboxes that are on a mailbox store

You can use the LDP tool to find all the accounts that have mailboxes on a particular mailbox store. This tool is included with the Microsoft Windows 2000 Support Tools package.

To use the LDP tool to find all the accounts that have mailboxes on a particular mailbox store, follow these steps:
1.Start Ldp.exe.
2.Click Connection, and then click Connect.
3.Enter the name of a domain controller, and then click OK.We recommend that you enter a domain controller in the root domain of the forest.
4.Click Connection, and then click Bind.
5.Enter the user name, the password, and the domain name of an administrative account, and then click OK.
6.On the View menu, click Search.
7.Click to select the "DC=domainname,DC=local" by Base DN check box.
8.Click the Filter box, and then type the following text:
msExchHomeServerName=Exchange virtual server name
9.Click Subtree, and then click Run.
10.Identify the users who have mailboxes on this store. Then, use the Active Directory Users and Computers snap-in to move the mailboxes to a different store or to delete the mailboxes.


Method 2: Use the LDP tool to search for mailboxes that are on a mailbox store

1.Start Ldp.exe.
2.Click Connection, and then click Connect.
3.Enter the name of a domain controller, and then click OK.
4.Click Connection, and then click Bind.
5.Enter the user name, the password, and the domain name of an administrative account, and then click OK.
6.On the View menu, click Tree.
7.Make sure that the Base DN box is blank, and then click OK.If the Base DN box is not blank, clear its contents, and then click OK.
8.Right-click the container that you want to search, such as the CN=Users container, and then click OK.
9.Click the Filter box, and then type the following:
(&(objectCategory=person)(objectClass=user)(msExchHomeServerName=/o=ORGANIZATION NAME/ou=ADMINISTRATIVE GROUP NAME/cn=Configuration/cn=Servers/cn=SERVER-NAME-TO-REMOVE))
10.Click Subtree, and then click Run.
11.When you have identified which users have mailboxes on this store, you can use Active Directory Users and Computers either to move the mailboxes to a different store or to delete the user's mailbox.

Method 3: Use Active Directory Users and Computers to browse for mailboxes that are on a mailbox store

1.Start Active Directory Users and Computers on a computer that has Exchange System Manager installed on it.
2.In Active Directory Users and Computers, click View, click to select the Advanced Features check box, and then click OK.
3.Click View, and then click Choose Columns.
4.In the Modify Columns box, click Exchange Mailbox Store in the Hidden Columns list, click Add, and then click OK to add the Exchange Mailbox Store to the Displayed Columns list.An Exchange Mailbox Store column appears in Active Directory Users and Computers that shows the mailbox store that a user has a mailbox on.
5.When you have identified which users have mailboxes on this store, you can use Active Directory Users and Computers either to move the mailboxes to a different store or to delete the user's mailbox.

Method 4: Use Active Directory Users and Computers to search for mailboxes that are on a mailbox store

1.Start Active Directory Users and Computers.
2.Right-click the domain that you want, and then click Find.
3.Click the Advanced tab, click Field, point to User, and then click Exchange Home Server.
4.In the Condition list, click Ends with, type the name of your Exchange computer, and then click Find Now.
5.If you are prompted to add the current criteria to your search, click Yes.
6.When you have identified which users have mailboxes on this store, you can use Active Directory Users and Computers either to move the mailboxes to a different store or to delete the user's mailbox.
The mailbox search results appear in the lower pane.

Method 5: Use the LDIFDE tool (Ldifde.exe) to create an export file that contains the mailboxes that are on a mailbox store

1.At a command prompt, type an LDIFDE command that is similar to the following. Then press ENTER.
ldifde -d "DC=ROOT,DC=COM" -f c:\output.txt -r "(&(objectCategory=person)(objectClass=user)(msExchHomeServerName=/o=ORGANIZATION NAME/ou=ADMINISTRATIVE GROUP NAME/cn=Configuration/cn=Servers/cn=SERVER-NAME-TO-REMOVE))"
2.Quit the command prompt.
3.Start Notepad or some other text editor, and then load the Output.txt file that you created in step 1 to view the mailboxes that are on the mailbox store.
4.When you have identified which users have mailboxes on this store, you can use Active Directory Users and Computers either to move the mailboxes to a different store or to delete the user's mailbox.

Thanks

Logu

logu_microsoft@hotmail.com
91-9841499143

Outlook Web Access – OWA in Exchange 2007:

In this article, we are going to discuss all the new features that are available in the exchange 2007 OWA and also related configuration. The OWA is handy for many users in accessing their email when compared to the outlook client when they are out of their organization, probably when they are travelling different places. They will be able to access their email with ease even though they don’t have the laptop.

Key new OWA features:

1.Web ready documents allow opening office docs.
2.Email headers view.
3.Customizable toolbars.
4.Out of Office configuration.
5.Deleted Item recovery.
6.Instant language options.
7.Cleaner Calendar reminders.
8.Multiple calendars and drag gable appointments.
9.Mobile device configuration options.
10.Change password interface.
11.Open other’s mailbox within OWA.

Light vs. Premium Client

Light Version:
1.For non-IE browsers.
2.For slow connections.
3.For older systems.
4.Most secure/best for kiosks
5.Contains basic access to all resource types.

Full Version:
1.More feature-rich.
2.Deeper interaction with mailbox content.
3.Drag and drop.
4.Access to file servers and SharePoint.

Thanks

Logu

Logu_microosft@hotmail.com
91-9841499143

Address List:

In this article, we are going to discuss about the functions of the address list in exchange server 2007 version. In simple words, address list contains the classified details of the contact address (user’s email address, mail contacts, public folder email address, distribution email address, etc). The address lists are built to make lookups more useable than the basic Global Address List. The Global Address list contains all the address in the exchange directory (in short contains all mail enabled objects), and by default this is available in all email clients. This pre-canned address book will suffice for small-midsized businesses. The custom address list can be created as per your company needs.

Global Address List:

1. A list from the AD with all mail-enabled containers in it.
2. By default, it is provided to every user within Outlook and OWA.
3. Additional GALs can be created for hosting environments that need isolation.

Offline Address Book:

1. Allow users to get AD info while offline.
2. It is available to both internal and external users.
3. Are distributed via web-site and via Public folder.

Dynamic Distribution Group:

1. Groups can be built based on AD properties like Department, State or Company.
2. Dynamic security group is not feasible; one dynamic distribution group is possible. For example, Suppose I need to create a group on the basis of company name and city location (custom attribute1). The above can be done by creating the dynamic distribution group. Any new addition which matches the above condition will be automatically added to the distribution group, that’s the reason why it s called as Dynamic.
3. Especially useful for location-specific communications.
4. Can’t be used as security groups.
5. Create them in the Group sub-node of the Recipient node.
6. Non-wizard filtering criteria can be used if you use the New-DynamicDistributionGroup cmdlet.
#New-DynamicDistributionGroup –Name “Groupname” –Alias “ABC_Company” –IncludedRecipeints “MailboxUsers,MailContacts” – OrganizationalUnit “Domain.com/Users” –ConditionalCompany “Domain”

Best Practice:

1.Address List:

a. Don’t create any unless you really need them, and then keep it simple.
b. Make list names clearly descriptive of contents.

2.Global Address List:

a. Stick with the default one if at all possible.
b. Create new ones only for client based isolation.

3.Dynamic Distribution List:

a. Make use of this group.
b. Don’t forget about the value of the non-wizard Dynamic lists.

Hope the above is informative.

Please feel free to contact me for any questions.

Thanks
Logu

Logu_microsoft@hotmail.com
91-98414 99143.

Public folder in the exchange server 2007:

In Simple words, the Public folder is just like a general forum which is used for posting mails, documents and other common information. Actually, usage of public folder has been overcome by SharePoint portal services. Exchange server 2007 is de-emphasized i.e., there is no change or improvement in the public folder architecture in the 2007 version. Microsoft no more support public folders. This article explains the working of the public folders in the exchange 2007 server.

Public folder function:

1. Public folder data is kept in the public folder database.
2. Multiple replicas of a public folder can be maintained on separate servers.
3. Any sort of folder data can be kept in a public folder.
4. Public folders can be given their own email address.
5. You can configure Send-as permission on a public folder.

Public folder Creation:

In the EMC, go to toolbox PFMC – Public folder management console.

#New-Publicfolder –name TESTPUBLICFOLDER –path ‘\’ –server ‘servername’

Assigning PF Permission and PF Email address:

1.Setting Permission can be done from Outlook or the EMS.

2.There are two ways to give admin permission via EMS:

a.Add-PublicFolderadministratorPermission - Per-PF.
b.Add-ExchangeAdministrator - General Admin rights, including to PF root.

3.The easiest way is to use Add-PublicFolderClientPermission to assign ownership

#Add-PublicFolderClientPermission –Identity \TESTPUBLICFOLDER –User USERALIASNAME –AccessRights FolderOwner

4.Check permission of the PF using the Outlook or in EMS with

Get-PublicFolderClientPermission
Set perms with Add/Remove/Set-PublicFolderClientPermission

#Get-PublicFolderClientPermission \TESTPUBLICFOLDER list

5.You can use either the EMC or the EMS to mail-enable a public folder.
#Enable-MailPublicFolder \TESTPUBLICFOLDER

6.Check whether a PF is mail-enabled

#Get-PublicFolder list mailenabled
#Get-MailPublicFolder

7.Send-As Permission can be done in the console.

Hope the above is informative.

Please feel free to contact me for any questions.

Thanks

Logu

Logu_microsoft@hotmail.com

91-98414 99143.

Best Practices for FSMO role placement:

In an Active Directory environment, some of your domain controllers (DCs) must be assigned certain special roles for your network to function properly. These special roles are called flexible single master operations (FSMO) roles, and DCs that hold such roles are called FSMO role holders. If you don't assign these roles properly, bad things can happen, so the focus of this article is on rules for proper placement of FSMO roles on AD-based networks. But before we proceed, please refer my blog session on FSMO roles.

Symptoms of FSMO Problems:

If one or more of your FSMO role holders has problems, bad things can happen. To help you troubleshoot such situations, the table below describes some of the symptoms that can occur when FSMO role holders go missing or don't work properly.

Symptom:

1. PDC Emulator
1. Users can't log on - If system clocks become unsynchronized, Kerberos may fail.
2. Can't change passwords - Password changes need this role holder.
3. Account lockout not working - Account lockout enforcement needs this role holder.
4. Can't raise the functional level for a domain - This role holder must be available when the raising the domain functional level.
2. RID Master
1. Can't create new users or groups - RID pool has been depleted.
3. Infrastructure Master
1. Problems with universal group memberships - Cross-domain object references need this role holder.
4. Domain Naming Master
1. Can't add or remove a domain - Changes to the namespace need this role holder.
2. Can't promote or demote a DC - Changes to the namespace need this role holder.
5. Schema Master
1. Can't modify the schema - Changes to the schema need this role holder.
2. Can't raise the functional level for the forest - This role holder must be available when the raising the forest functional level.

Rules for FSMO Role Placement

Since FSMO roles are crucial for the proper functioning of an AD-based network, it's a good idea to get them right from the planning stage of your deployment. By default, when you install the first DC of your forest root domain, this first DC holds all five FSMO roles. When you install the first DC of any other domain in your forest, that DC will hold all three domain FSMO roles (PDC Emulator, RID Master, and Infrastructure Master). Depending on the complexity of your network, this FSMO role must be placed.

Rule 1: The PDC Emulator and RID Master roles should be on the same machine because the PDC Emulator is a large consumer of RIDs.

Tip: Since the PDC Emulator is the role that does the most work by far of any FSMO role, if the machine holding the PDC Emulator role is heavily utilized then move this role and the RID Master role to a different DC, preferable not a global catalog server (GC) since those are often heavily used also.

Rule 2: The Infrastructure Master should not be placed on a GC.

Tip: Make sure the Infrastructure Master has a GC in the same site as a direct replication partner.

Exception 1: It's OK to put the Infrastructure Master on a GC if your forest has only one domain.

Exception 2: It's OK to put the Infrastructure Master on a GC if every DC in your forest has the GC.

Rule 3: For simpler management, the Schema Master and Domain Naming Master can be on the same machine, which should also be a GC.

Exception: If you've raised your forest functional level to Windows Server 2003, the Domain Naming Master doesn't need to be on a GC, but it should at least be a direct replication partner with a GC in the same site.

Rule 4: Proactively check from time to time to confirm that all FSMO roles are available or write a script to do this automatically.

Tip: If any FSMO role holders at a remote site are unavailable, check first to see if your WAN link is down.

Hope the above is informative.

Please feel free to contact me for any questions.

Thanks

Logu

Logu_microsoft@hotmail.com

91-98414 99143.

Exchange 2007 Database

This article explains the architecture of the exchange 2007 database and also about its new feature when compared to the previous versions. As we aware exchange 2003 database uses the .edb (rich text file) and .stm files(streaming file). For more details please refer my blog session. In simple words, the rich text file holds the actual messages, the rich text information and the Message Application programming (MAPI) information. The streaming file holds non-MAPI information like MIME contents. There is no more .stm file, all stored in .edb file.

How Exchange stores data:

Database built on a heavily extended version of JET. The JET Database is an old and simple database type which is used for all mail storage in the exchange 2007. Why Microsoft relying on the JET still?, it’s a bit interesting stuff. Microsoft doesn’t want to change the database from JET to SQL database because already in exchange 2007 has enough changes like 64 bit architecture and many other new improved features. Single Instance Storage (SIS) provides large disk space saving. SIS is nothing but, when you send 1 MB attachment mail for 10 users, actually only one copy (1 MB of file) is stored in the DB. Databases use transaction logs (and memory) to initially store data. The mail flow exist as below

All incoming mails à transaction log à Database

Transaction log is like heart beat of the database. All the message routing is logged in a file before getting into the database (edb file) is called the transaction log. The analogy behind this transaction log is used for the restoring the recent data of the database in times of disaster. After successful backup, the committed logs are removed in order to avoid the disk space accumulation. So the last full backup copy plus the uncommitted transaction log will reproduce the recent copy of the database.

Storage Capacity:

In exchange, the maximum storage limit for a database is restricted to certain level, whereas in exchange 2007, it is unlimited theoretically. Please find the difference b/w the standard and enterprise edition in terms of the storage capacity.

In Standard edition:Storage group – up to 5,Database per SG – up to 5,Database limit – 16 TB.
Enterprise edition: Storage group – up to 50,Database per SG – up to 50,Database limit – 16 TB.

The above are the storage limits of the databases, but there are some size caps. The size caps are nothing but artificial size limit set at the registry level. For example for standard edition, there is artificial 50 GB cap on database sizes (for SP1 = 150 GB). This can be increased as per your wish and need, by just creating some entry in the registry as below.

HKLM\system\currentcontrolset\services\MSexchangeIS\servername\private{respective-DB-GUID}

In the above location just add a new DWORD value “Database Size Limit in GB” and set the decimal value as 200 (in this case increasing the size limit to 200 GB). In addition, the default mailbox size limit is 2 GB (can be changed).

Difference b/w exchange 2007 database and the previous version:

The following the differences between the exchange 2007 database and the exchange database of older version.

1. The name of the store has been changed to Database.
2. There is no more .stm file anymore. All data is in the .edb file.
3. Transaction logs have shrunk from 5 MB to 1 MB.
4. Transaction log numbering limits have been expanded from a million to 4 billion.
5. Lost Log Resilience keeps last several log files in memory.

Relationship b/w Storage groups and Database:

1. Storage groups are virtual containers for databases.
2. They can hold up to five databases each.
3. Transaction logs are handled at the storage group level.
4. LCR – Local Continuous Replication - is a new feature of exchange 2007 will enables us to have a copy of the database in some other location. LCR can be used only if you use single database per storage group.

Guidelines for Best practices:

1. Try 1:1 model for storage groups and databases.
2. Isolate DB and transaction logs on separate disk for redundancy purpose.
3. Leave Circular logging disabled.
4. Perform regular Full backups.
5. Check the available disk space for the transaction logs because it increases in faster rate and occupies plenty spaces.
6. If you have multiple DB’s, set maintenance schedules so they don’t conflict each other.
7. If it is 1:1 model, make use of LCR-Local Continuous Replication option.
8. Don’t forget about the artificial size cap.

Hope the above is informative.

Please feel free to contact me for any questions.

Thanks

Logu

Logu_microsoft@hotmail.com

91-98414 99143.

Managing File System Inconsistencies and Disk space in UNIX\Solaris:

This article explains how to manage disk space and file system inconsistencies. In general, Unix file system uses a set of tables to keep track of used inodes and available blocks. Inconsistencies will arise, for example, abrupt termination of the operating system. The reason for inconsistencies are listed below

1. Software error in the kernel.

2. Turning off the system without proper shutdown procedure.

3. Defective hardware, such as problem with the disk.

fsck Command:

Used to find the inconsistencies and repair them.

Syntax:

#fsck {option} {device}

Options

-F {fstype} – limit to check the specified file system.
-m – check but do not repair, for checking the status of the file system.

df Command:

Used to monitor disk space usage at file system level, also used to determine the following,

1. The amount of disk space occupied by currently mounted or unmounted file systems.
2. The total amount of the used and available space.
3. The fraction of the file system’s total capacity that has been used.

Syntax:

#df {-F fstype} {option} {file system}

du Command:

Used to get the report on disk usage at the directory and file level, also used to determine the following,

1. Total space allocated to a directory.
2. Total space allocated to a directory subtree.
3. Total space allocated to a non-directory file.

Syntax:

#du {option} {file}

quot Command:

Used to get the report on disk usage by user name, if you want to know how much space is being used by each user on a given file system, can make use of this command.

Syntax:

#quot {option} {filesystem}

Hope this is informative.

Thanks

Logu

Logu_microsoft@hotmail.com
91-98414 99143

Managing Hard and Symbolic Links in Solaris/Unix:

This article explains the purpose and usage of hard and symbolic links. A link is a file that points to another file. There are two kinds of link available

1.Hard Link:

a. A Hard Link is a pointer to a file that is indistinguishable from the original file.

b. Any changes made to a file are effective regardless of the name used to refer to the file – the link file or the original file name.

c. The link and the file are on the same file system because both have the same inode number.

d. A hard link can only point to a file, not to a directory.

e. You cannot create a hard link file without having the existing file.

f. The hard link file will consume the same amount of the disk as that of the original file.

g. If you delete the link file, the other will exist and the reverse is also applicable.

Syntax of the Hard Link file:

To create a hard link file,
#ln {source} {Target}

To remove the same file,
#rm {linkfile}

2.Symbolic Link:

a. A Symbolic Link is an indirect pointer to a file and it can span the file systems.

b. A symbolic link can be pointed to either file or directory.

c. You can create a symbolic link without having the existing file.

d. The symbolic link file will have the different inode number.

e. The symbolic link file will just have the details of the pointer information of the original file alone. Hence it won’t consume the same space as that of the original file.

f. It is just like a shortcut in the Windows.

g. If you delete the shortcut link file, the original file will exist. The reverse is obviously not applicable. It is better to clean up the shortcut files i.e, symbolic file before deleting the source file.

Syntax of the Symbolic Link file:

#ln –s {Source} {Target}

Thanks

Logu

Logu_microsoft@hotmail.com
91-98414 99143