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Posted by David Portas on 08/07/06 19:33
Bjørn Augestad wrote:
>
>
> I'm no NTFS expert either, so I read the tech spec for NTFS at
> http://technet2.microsoft.com/WindowsServer/en/library/59a9462a-cbdd-45e7-828b-12c6cd9ae4781033.mspx?mfr=true
>
> Here's a quote:
> NTFS Change Journal
>
> As files, folders, and other NTFS objects are added, deleted, and
> modified, NTFS enters change journal records in streams, one for each
> volume on the computer.
>
> My interpretation, hopefully wrong, is that NTFS journal entries will be
> written to disk whenever a file is modified. This will lead to disk head
> movement and decreased performance on a busy disk, won't it?
>
The point of NTFS journaling is to protect the integrity of file system
META-DATA - avoiding the integrity issues inherent with FAT. NTFS
doesn't guarantee data consistency. For that SQL Server relies on the
transaction log. Your transaction logs can and should be placed on
separate drives to avoid disk contention.
"The Windows NT Filesystem (NTFS) is a journaling, or transactional
file system. This means that any I/O that alters the file system data
or meta-data (directory structure, etc.) is completed atomically so
that either all of the changes are completed"
http://www.microsoft.com/technet/archive/termsrv/evaluate/indcomp/tsunix.mspx?mfr=true
"NTFS does not do data journaling"
www.cs.wisc.edu/adsl/Publications/sba-usenix05.pdf
"An important feature of NTFS is journaling. Before a change is made to
the metadata of a file, a transaction is logged in the $LOGFILE."
http://www.mcmillan.cx/ntfs.html
--
David Portas, SQL Server MVP
Whenever possible please post enough code to reproduce your problem.
Including CREATE TABLE and INSERT statements usually helps.
State what version of SQL Server you are using and specify the content
of any error messages.
SQL Server Books Online:
http://msdn2.microsoft.com/library/ms130214(en-US,SQL.90).aspx
--
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