John
Thu Mar 27 16:39:49 PDT 2008
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In Exchange 2007, an IO to the database is 8K. An IO to the logs cam be =
512 bytes to 1MB. If you use a backup program that does not leverage =
snapshots and instead uses backupo API, then use 64K because many backup =
API applications read in 64K chunks. If you use snapshots, it really =
depends on the cache architecture of your storage. COnsult your storage =
vendor.
"Tarek Ismail" <Tarek_877_nospam@hotmail.com> wrote in message =
news:9E859CD2-EBC6-4DA3-9B94-CC56CD45708F@microsoft.com...
Microsoft Exchange Server 2007 writes data in multiples of 8-kilobyte =
(KB) I/O operations, and I/O operation to a database can be from 8 KB to =
1 megabyte (MB). Therefore, make sure that the starting offset is a =
multiple of 8 KB.
Failure to do so may cause a single I/O operation spanning two tracks, =
causing performance degradation.
If your storage vendor does not have any specific recommendations, =
Microsoft recommend that you use 64 KB.
--=20
Tarek Ismail=20
Infrastructure Consultant
OMS
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<DIV><FONT size=3D2>In Exchange 2007, an IO to the database is 8K. =
An IO to=20
the logs cam be 512 bytes to 1MB. If you use a backup program that =
does=20
not leverage snapshots and instead uses backupo API, then use 64K =
because many=20
backup API applications read in 64K chunks. If you use snapshots, =
it=20
really depends on the cache architecture of your storage. COnsult =
your=20
storage vendor.</FONT></DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<DIV> </DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<BLOCKQUOTE dir=3Dltr=20
style=3D"PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV>"Tarek Ismail" <<A=20
=
href=3D"mailto:Tarek_877_nospam@hotmail.com">Tarek_877_nospam@hotmail.com=
</A>>=20
wrote in message <A=20
=
href=3D"news:9E859CD2-EBC6-4DA3-9B94-CC56CD45708F@microsoft.com">news:9E8=
59CD2-EBC6-4DA3-9B94-CC56CD45708F@microsoft.com</A>...</DIV>
<DIV><FONT face=3DTahoma color=3D#0000ff size=3D2>
<DIV> </DIV>
<DIV>Microsoft Exchange Server 2007 writes data in =
multiples of=20
8-kilobyte (KB) I/O operations, and I/O operation to a database can be =
from=20
8 KB to 1 megabyte (MB). Therefore, make sure that the =
starting=20
offset is a multiple of 8 KB.</DIV>
<DIV> </DIV>
<DIV>Failure to do so may cause a single I/O operation spanning two =
tracks,=20
causing performance degradation.</DIV>
<DIV> </DIV>
<DIV>If your storage vendor does not have any specific =
recommendations,=20
Microsoft recommend that you use 64 KB.</DIV></FONT></DIV>
<DIV><FONT face=3DTahoma color=3D#0000ff size=3D2></FONT><FONT =
face=3DTahoma=20
color=3D#0000ff size=3D2></FONT><BR>-- <BR>Tarek Ismail =
<BR>Infrastructure=20
Consultant<BR>OMS</DIV></BLOCKQUOTE></BODY></HTML>
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