Re: Minimal configuration, suggestions wanted.

From: ben brugman (ben_at_niethier.nl)
Date: 04/07/04 

Date: Wed, 7 Apr 2004 13:01:22 +0200

Going with your suggestions,
suppose you have split the total RAID device in 3 groups
of disks (fysical separate), how would you place

1 OS
2 Logging
3 Data
4 Backupdata
5 Transactionlog backup

Have I missed anything ?
Or are 2 groups enough ?
Or do I need more groups ?

> on how much data you are willing to loose. If you can afford to loose up
to
> 15 minutes worth of transactions then use a 15 minute interval etc. Just

If I go from estimates of MTBF of disks the chance of
losing a mirrored disk is extremely small. So the chance
of loosing up to 15 minutes of data is extremely small.
Loosing the complete system because of a major
dissaster (fire for example) looks more likely and then
you loose everything since the last time you brought
the backup to outside of the 'box' or the computerroom.
Because for a minimal system bringing the data out of the
room more than once or twice a day would probably be a
problem.

(Calculation for 2 disks failing, assuming a MTBF of 300000 hours,
that a failed disk is spotted with in 24 hours. I get a failure of
two disks every once in 1/(24/300000)^2 days = 156250000 days)

Two of my problems :

1. Backup of the transaction log is not a 'backup' but a 'move' of the
'content',
so how do I protect the backup of the transaction log, because at that
moment
it is the only 'copy' of that data in existence. (Still mirrored I would
suggest).

2. If part of the chain of transactionlogs (active of backupped) is lost the
datafiles are worthless, so I do not understand that the datafiles
should be on a separate disk.
(Performance not being a consideration).

Thanks for your thoughts.

ben brugman

"Andrew J. Kelly" <sqlmvpnoooospam@shadhawk.com> wrote in message
news:uRptBADHEHA.2260@TK2MSFTNGP09.phx.gbl...
> Keep in mind that a server with a 200GB db and moderate load may not be
the
> same for a 10GB db with light load and this is addressing the latter as
you
> asked. A RAID 0+1 will give the most fault tolerate Raid with good
> performance as well. If the load is light enough (not a lot of
> transactions) then you can probably get away with a good size (meaning #
of
> disks not size of disks) RAID 0+1 or even 1+0 that has everything on it.
> But it is usually best to place the logs on their own RAID 1 and separate
> from the data for performance reasons. With a minimal configuration a
good
> raid is essential along with proper backups. A full backup once a night
is
> usually OK for most applications. The frequency of the log backups depend
> on how much data you are willing to loose. If you can afford to loose up
to
> 15 minutes worth of transactions then use a 15 minute interval etc. Just
> ensure the backups are not done to the same drive the logs or data reside
> on.
>
> --
> Andrew J. Kelly SQL MVP
>
>
> "ben brugman" <ben@niethier.nl> wrote in message
> news:u1zBcW7GEHA.688@tk2msftngp13.phx.gbl...
> > Minimal configuration.
> > (Performance is not an issue).
> >
> > Dataloss should not happen. (But we do not account
> > for real dissasters, for example a big fire destroying
> > the complete production center, resulting
> > in the dataloss of 24 hours would be acceptable.)
> >
> > The shop runs 7 x 24 hours.
> > Most is done during office hours.
> > Some is done during all day.
> > At night the system must be available but it is
> > used very limited.
> >
> > Once a day a tape goes from the production machine to an
> > offsite safe.
> > The total amount of data has a disk footprint off
> > between 1 and 10 Gigabytes.
> >
> > Offcourse there is a production machine and
> > a standby machine probably in another location.
> > (The second machine will be used for testing and
> > practicing procedures.)
> >
> > Raid is required, raid protects agains single disks failures,
> > but what are the options for more protection ?
> > What configuration is considered minimal in these circumstances ?
> > Esspecially what to do with the disks ?
> > (OS / Logging / Data / Backupdata / Transactionlog backup) ?
> > What can be combined and what can not be combined ?
> > And how often to do the transactionlog backup ?
> > (Side question what "route" should the transactionlog(-backup)
> > take).
> >
> >
> > Keep in mind : We are looking for a minimal configuration.
> >
> > Later on we will also looking for a 'larger' configuration with
> > more performance, a larger database etc. (But still no super
> > configuration. Something like 100-200 Gigabyte and more load).
> >
> > Thanks for your thoughts,
> > ben brugman.
> >
> >
>
>

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