hi to all.

i am not able to understand what is
meant by battery backup
what is it used for .
how different is it from regular backup.
what is meant by battery backup of-
disk cache.


thank's
naresh

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Hi Naresh,

I'm not sure if this is what you are talking about but I found the following:

"Controller write caching can also speed up SQL Server I/O. The problem with this is that SQL Server will not know about the write caching, and will assume that when it writes a page to disk, that it was written successfully to disk. While this will be the case in most instances, it may not always be the case. If the server should fail before the data in the cache has been written to disk, then that data will be lost and your SQL Server databases may become corrupted.

While a battery backup for the cache can help reduce this problem, they introduce their own problems. For example, what if the server's motherboard fails and you need to move the drives to a new server. Will you be able to also move the cache controller to the new server, and will the data being backed up still be available in the new server? I personally never use write caching. The potential benefits don't outweigh the potential problems. To find out how to turn our I/O controller's write caching ability off and on, you will need to check your I/O controller's vendor. [6.5, 7.0, 2000]" from http://www.swynk.com/sqlhome/tips/mcgeheegensql4.asp

Also check out this knowledge base article from Microsoft:

http://support.microsoft.com/defaul...B;en-us;q230785

__________________
Best,

Susan
My Weblog about studying for MS 70-229 (Notes and Links)
http://ix.1sound.com/dbagirl

Last edited by sjgross on 12-17-02 at 07:28 PM

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thank's susan.

buddy you look dam good in sql yaar!!

that was nice of u. your message has

greatly helped me to understand

what is all about write cache and

battery backup.


thank's once again

naresh

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