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New Message on MumbaiUserGroup
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From: hereiam_always
Message 1 in Discussion
When to Use Transactional NTFS[This topic is pre-release documentation and
is subject to change in future releases.]
Any application can use Transactional NTFS (TxF) to preserve the integrity of
data on disk during unexpected error conditions. The following sections in this
topic provide examples of scenarios for you to use TxF. Saving a File
Saving a file is a common and typically simple operation. However, if a
computer fails while an application is saving information to disk, the result
can be catastrophic, because the user data can be corrupted by a file save
operation that is partially completed. Robust applications often perform
complex sequences of file copies and file renames to ensure that data is not
corrupted if a system fails.
TxF makes it simple for an application to protect file save operations from
system failure. To save a file safely, the application opens the file in
transacted mode, saves the file, and then commits the transaction. If the
system fails during the file save, then TxF automatically restores the file to
the state that it had before the file save began, which avoids file corruption.
Multi-File Updates
TxF is even more important when a single logical operation affects multiple
files. For example, if you want to use a tool to rename one of the HTML or ASP
pages on a Web site, a well-designed tool would also fix all links to use the
new file name. However, a failure during this operation leaves the Web site in
an inconsistent state, with some of the links still referring to the old file
name. By making the file rename operation and the link fixing operation a
single transaction, TxF ensures that the file rename and link fix succeed or
fail a single operation.
Consistent Concurrent Updates
TxF isolates concurrent transactions. If an application opens a file for a
transactional read while another application has the same file open for a
transactional update, TxF isolates the affects of the two transactions from one
another. In other words, the transactional reader always views a single,
consistent version of the file, even while that file is in the process of being
updated by another transaction.
An application can use this functionality to allow customers to view files
while other customers make updates. For example, a transactional Web server can
provide a single, consistent view of files while another tool concurrently
updates those files.
Note TxF does not support concurrent updates by multiple writers in different
transactions. TxF supports only a single writer with multiple concurrent and
consistent readers.
Multi-Machine Updates
Because TxF can can be used in distributed transactions by using Distributed
Transaction Coordinator (DTC), you can use transactional properties when
modifying files on multiple machines. To continue with the previous consistent
concurrent update example in this topic, if you maintain a Web farm and want to
rename a page, you can use TxF to ensure that all replicas of a page are
renamed successfully and all links fixed.
Because it is easy to make transactional updates in a script, TxF can also
process datacenter administration tasks. For example, if an administrator must
change files on hundreds of servers, the administrator can write a script to
automate the task. TxF ensures that, if there is a failure on any of the
machines, all of the file operations are undone, and restores the servers to a
consistent state.
I think this doc will help in all. (found on MSDN)
Enjoy,
Nilesh Joshi
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