How to back up raw devices.
and your username is???
We're getting a pilot data warehouse machine up and running, and the DBA
wishes to utilize raw devices, the first in our environment.
While I know dd can be used for this purpose, I was wondering if cpio
might also be an option. If so, which would be better?
Comments/opinions/etc. requested.
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John Kotches
and your username is??? wrote:
>
> We're getting a pilot data warehouse machine up and running, and the DBA
> wishes to utilize raw devices, the first in our environment.
>
> While I know dd can be used for this purpose, I was wondering if cpio
> might also be an option. If so, which would be better?
>
> Comments/opinions/etc. requested.
>
Point 1:
cpio only works if there's a file system to back up. If the database
is using a raw device you can't back it up to tape.
Point 2:
dd would be a safe, but inefficient method to backup your database.
You would be required to write block for block every byte of each raw
partition.
Point 3:
every commercial database I've used has had some mechanism included
with the engine for backups. Get to know this piece of software.
Test it out backups/restores with this database. Make sure it works.
I'm not mentioning any database engine names where restoration might
be an issue in a public forum such as this. However, if you want to
discuss one databases archive/restore weaknesses privately I'd be
delighted to.
--
___________________________________
/ John Kotches is cybernetically: /\
/ jkot...@pobox.com (Personally) / /
/ jo...@sigg.com (Professionally) / /
/ / /
/ Technology: no place for wimps! / /
\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\/
Henry Greene
In article <Pine.GSO.3.96.970308160510.12755A-100000@thumper>,
bo...@visi.com says...
> We're getting a pilot data warehouse machine up and running, and the DBA
> wishes to utilize raw devices, the first in our environment.
>
> While I know dd can be used for this purpose, I was wondering if cpio
> might also be an option. If so, which would be better?
DD is your only standard unix util option. Your other two options would
be to purchase a tape management system (Networker, ADSM, etc) that
supports RAW file systems. You know have tape management, but this does
not necessarily buy you any solution that is integrated to back up your
database. Your next solution would be to purchase a backup solution for
your database (vs. writing your own scripts) that is integrated into a
tape management system and supports your database.
My recommendation would be to purchase software to manage database
backups and restortions that is integratred into your tape management
system. The days of writing cpio, tar, dd and other unix scripts are
pretty much over for DBAs. These scripts never assist in restoring
databases and they certainly don't tell you were files are on tapes.
--
Neil Greene "Money doesn't always bring happiness.
Senior System Engineer / Oracle DBA People with ten million dollars
are
MCI Systemhouse, Inc. no happier then people with nine
million
email: ngr...@laoc.SHL.com dollars." --- Hobart Brown
Michael G. Beirne
In article <332267...@pobox.com>, John Kotches <jkto...@pobox.com> wrote:
>and your username is??? wrote:
>>
>> wishes to utilize raw devices, the first in our environment.
>>
>> While I know dd can be used for this purpose, I was wondering if cpio
>> might also be an option. If so, which would be better?
>>
>>
>
>Point 1:
>cpio only works if there's a file system to back up. If the database
>is using a raw device you can't back it up to tape.
Correct.
>Point 2:
>dd would be a safe, but inefficient method to backup your database.
>You would be required to write block for block every byte of each raw
>partition.
dd has bs= ib= ob= parameters to fix the blocksize problem, but
will exit for any output errors. This will leave you with a partial
backup on the tape. Dds error handling capability leaves much to be desired.
It also won't handle backups that need to span tapes.
>Point 3:
>
>every commercial database I've used has had some mechanism included
>with the engine for backups. Get to know this piece of software.
>Test it out backups/restores with this database. Make sure it works.
>I'm not mentioning any database engine names where restoration might
>be an issue in a public forum such as this. However, if you want to
>discuss one databases archive/restore weaknesses privately I'd be
>delighted to.
Sybase has a good backup program, but Oracle does not, at least not yet.
Exporting the data to files and then using dump, tar or cpio to backup
the files should always work though. This, of course, requires you
to have enough disk space for the data and the exported data.
Legato Networker is supposed to have some support for raw partition
database backups. I haven't used it though, so I can't recommend it.
Mike Beirne
--
Michael G. Beirne | 1509 W. Oakdale 1st, Chicago,IL 60657-4010, (773)348-8438
bei...@limerick.chi.il.us or bei...@wwa.com
and your username is???
On 9 Mar 1997, Michael G. Beirne wrote:
> In article <332267...@pobox.com>, John Kotches <jkto...@pobox.com> wrote:
> >and your username is??? wrote:
> >>
> >> We're getting a pilot data warehouse machine up and running, and the DBA
> >> wishes to utilize raw devices, the first in our environment.
> >>
> >> While I know dd can be used for this purpose, I was wondering if cpio
> >> might also be an option. If so, which would be better?
> >>
> >> Comments/opinions/etc. requested.
> >>
> >
> >Point 1:
> >cpio only works if there's a file system to back up. If the database
> >is using a raw device you can't back it up to tape.
>
> Correct.
Was fairly certain of that, as nothing I read explicitly stated that it
would. Of course, nothing explicitly stated it wouldn't, either.
> >Point 2:
> >dd would be a safe, but inefficient method to backup your database.
> >You would be required to write block for block every byte of each raw
> >partition.
>
> dd has bs= ib= ob= parameters to fix the blocksize problem, but
> will exit for any output errors. This will leave you with a partial
> backup on the tape. Dds error handling capability leaves much to be desired.
> It also won't handle backups that need to span tapes.
That last part (dd's non-spanning of tapes) has bothered me from the
outset, as this box has 60 GB of drives on it. Writing to compressed
DLT drives will require some careful planning on where to stop and switch
tapes.
> >Point 3:
> >
> >every commercial database I've used has had some mechanism included
> >with the engine for backups. Get to know this piece of software.
> >Test it out backups/restores with this database. Make sure it works.
> >I'm not mentioning any database engine names where restoration might
> >be an issue in a public forum such as this. However, if you want to
> >discuss one databases archive/restore weaknesses privately I'd be
> >delighted to.
>
> Sybase has a good backup program, but Oracle does not, at least not yet.
> Exporting the data to files and then using dump, tar or cpio to backup
> the files should always work though. This, of course, requires you
> to have enough disk space for the data and the exported data.
>
> Legato Networker is supposed to have some support for raw partition
> database backups. I haven't used it though, so I can't recommend it.
I believe Legato 4.2.5 now supports raw backups. However, I'm not
touching that one yet, either.
Due to the headaches I've been experiencing attempting to plan out a
backup/recovery method, my recommendation is to go with filesystems, and
not raw devices. If they want speed, go with Veritas (VxFS).
At any rate, I think the pilot will utilize a dual backup
strategy--ufsdump for filesystems, dd for the raw devices.
Thanks all for your advice and comments.
Philip Leung
John Kotches <jkot...@pobox.com> writes:
>and your username is??? wrote:
>>
>> We're getting a pilot data warehouse machine up and running, and the DBA
>> wishes to utilize raw devices, the first in our environment.
>>
>> While I know dd can be used for this purpose, I was wondering if cpio
>> might also be an option. If so, which would be better?
>>
>> Comments/opinions/etc. requested.
>>
>Point 1:
>cpio only works if there's a file system to back up. If the database
>is using a raw device you can't back it up to tape.
>Point 2:
>dd would be a safe, but inefficient method to backup your database.
>You would be required to write block for block every byte of each raw
>partition.
My Sybase technical support contact told me never to use dd to back up raw
device because it wouldn't work. The advice was always to use database
dumps (to binary files). That was when Sybase was at version 4.9. Doubt
if things have changed much since then on this issue.