Device vs Database 
Author Message
 Device vs Database
Hello All,

Can someone please explain the relationship between a database device, a
log device,
and a database?

Does every database need its own database device and log device?
If not can you put multiple databases in one device?
Or can a single database span multiple devices?
What are the efficiency implications of each of these.

Thanks in advance,
-K-



Sat, 23 Dec 2000 03:00:00 GMT
 Device vs Database

Hi
A MS-SQL db consists of a part holding the data and a part holding the
transaction log.
You could create your db with the data AND the log part sharing a data .dev
BUT you would loose the possible control of the size of the log part.
If you create your db with separate data and log .dev, you also will be able
to take advantage of more than one disk/disk-subsystem, that is the access
to the data part and to the log part dosnt compete for bandwidth towards the
disk if separate disk-subsystems(best). In case you (just) use separate
disks the advantage is still great.
If you create your db with separate data and log .dev, you could gain some
performance putting the log part on a FAT partition, because the filesystem
access itself isnt at filesystem logged operation on FAT.
It is quite easy to expand your db online, edit->expand->data->new(create
new data .dev on adequate disk-subsystem)->expand_now and you are done.

kind regards

-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-
 Flemming V. Mortensen
Job   Privat
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Niels Bohrs All 185  Kongebakken 1
DK-5220 Odense S?  DK-5700 Svendborg
phone +45 66156368  phone +45 62210781
fax      +45 66155330  fax      +45 62210781


-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-

Quote:

>Hello All,

>Can someone please explain the relationship between a database device, a
>log device,
>and a database?

>Does every database need its own database device and log device?
>If not can you put multiple databases in one device?
>Or can a single database span multiple devices?
>What are the efficiency implications of each of these.

>Thanks in advance,
>-K-



Mon, 25 Dec 2000 03:00:00 GMT
 Device vs Database

Quote:
>3) Multiple databases can be on the same device.

The explanations are all correct, but I would like to add that while
it is possible to put multiple databases on the same device, it is NOT
a good idea.  Life can get very complicated later on that way, and
there is no reason not to keep things separate.

Roy



Tue, 26 Dec 2000 03:00:00 GMT
 
 [ 5 post ] 

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