What problem could happens if i have data and log in the same device
or if i have 2 data device with the same name:

look at: (runing sp_helpdb)
nrdata27 359.0 MB data only
341808
nrdata27 298.0 MB log only
305152
nrdata27 683.0 MB data only
662176
nrdata27 292.0 MB log only
299008
nrdata27 405.0 MB data only
388064

In article <84e1563a.0309090357.61548fca@posting.google.com >,
ofercohen@allot.com says...
> What problem could happens if i have data and log in the same device
> or if i have 2 data device with the same name:
>
> look at: (runing sp_helpdb)
> nrdata27 359.0 MB data only
> 341808
> nrdata27 298.0 MB log only
> 305152
> nrdata27 683.0 MB data only
> 662176
> nrdata27 292.0 MB log only
> 299008
> nrdata27 405.0 MB data only
> 388064

Device names must be unique within the same server.

What you see above is not two devices with the same name, but
multiple fragments ("chunks of a database") allocated on the same
device. Run sp_helpdevice and you will see that "nrdata27"
appears only once.

Data & log can be mixed in two different ways. The first is the
way that affects you from the above output - data and log are
"logically separated" in that no device fragment has both data &
log mixed on the same fragment. If they were mixed (sp_helpdb
would show "data and log"), then transaction dumps (incremental
backups) are disallowed.

Even though your data & log are logically separated, they are
still physically mixed, in that the same device contains both
data & log, albeit in different fragments. This is a point of
failure because if you lose that device, you may only recover up
to your last good backups.

If data & log are physically separated (completely different
devices) then even if you lose your data device(s), as long as
your log device(s) remains healthy you can take a special post-
disaster transaction dump, which you then reload to recover all
transactions committed up to the moment of disaster.

This is discussed in detail in the System Administrator Guide.

Regards,
--
Joe Woodhouse
Principal Consultant (former Sybase Technical Evangelist)
Prima Donna Consulting Pty Ltd
(IT. Business. Law. Children's Parties.)