Backups/Restores

Backups/Restores

Post by Thomas Shann » Thu, 18 Apr 2002 23:58:27



I would like to get some input on our backup/restore scheme.  First, I
work in a production environment and do not have the option of testing
our scheme.  We have several different UNIX (Solaris) systems running
multiple instances of Informix 9.2xxx.  We are using raw space for our
databases.  The disks are EMC and are mirrored using EMC software.  We
use ontape to do a level 0 database backup nightly.  These are done to
disks, which are then backed up to tape via UNIX.  Most of  the
databases are not logged, but a logical log backup is performed daily
on all.  We perform periodic dbschemas and store them on disk
also.
I guess my two main questions would be;
1)      Is there anything that I should be doing that Im not? And
2)      How would I restore in the event of a disk failure?  I understand
the ontape -r, but Im not sure how to get to that
point.  Would the dbspaces have to be created manually, before using
the dbschema to recreate the tables, indexes, etc?
 
 
 

Backups/Restores

Post by David Ste » Fri, 19 Apr 2002 00:29:24



> I would like to get some input on our backup/restore scheme.  First, I
> work in a production environment and do not have the option of testing
> our scheme.  We have several different UNIX (Solaris) systems running
> multiple instances of Informix 9.2xxx.  We are using raw space for our
> databases.  The disks are EMC and are mirrored using EMC software.  We
> use ontape to do a level 0 database backup nightly.  These are done to
> disks, which are then backed up to tape via UNIX.  Most of  the
> databases are not logged, but a logical log backup is performed daily
> on all.  We perform periodic dbschema’s and store them on disk
> also.
> I guess my two main questions would be;
> 1)      Is there anything that I should be doing that I’m not? And
> 2)      How would I restore in the event of a disk failure?  I understand
> the “ontape -r”, but I’m not sure how to get to that
> point.  Would the dbspaces have to be created manually, before using
> the dbschema to recreate the tables, indexes, etc?

It is my understanding that to be safe, you should do somehow both
logical and physical backups.

The book of Curtis Preston ("Unix backup & recovery") calls logical
backups what you obtain via "dbexport" or "onunload" (it sounds like you
are not running a logical backup).

This book also contains some scripts for Informix backup that you may
wish to use.

 
 
 

Backups/Restores

Post by Xuanhai Carmichae » Fri, 19 Apr 2002 02:11:51


   My backup schemes ares as follow:
   1.  ontape level 0 of each instance, nightly
   2.  dbexport of each important database, to disk, nightly.
   3.  ontape -c, continuous logical logs backup, during the         day.
   To restore:
    ontape -r is rarely needed.  But if it is needed, the logical logs backup is already included in ontape -r.
    Most of the times, we need to restore individual tables, so dbexport becomes very useful.

I would like to get some input on our backup/restore scheme.  First, I
work in a production environment and do not have the option of testing
our scheme.  We have several different UNIX (Solaris) systems running
multiple instances of Informix 9.2xxx.  We are using raw space for our
databases.  The disks are EMC and are mirrored using EMC software.  We
use ontape to do a level 0 database backup nightly.  These are done to
disks, which are then backed up to tape via UNIX.  Most of  the
databases are not logged, but a logical log backup is performed daily
on all.  We perform periodic dbschema’s and store them on disk
also.
I guess my two main questions would be;
1)      Is there anything that I should be doing that I’m not? And
2)      How would I restore in the event of a disk failure?  I understand
the “ontape -r”, but I’m not sure how to get to that
point.  Would the dbspaces have to be created manually, before using
the dbschema to recreate the tables, indexes, etc?

 
 
 

Backups/Restores

Post by kaka » Fri, 19 Apr 2002 16:17:23



> My backup schemes ares as follow:
>    1.  ontape level 0 of each instance, nightly
>    2.  dbexport of each important database, to disk, nightly.
>    3.  ontape -c, continuous logical logs backup, during the         day.
>    To restore:
>     ontape -r is rarely needed.  But if it is needed, the logical logs backup is already included in ontape -r.
>     Most of the times, we need to restore individual tables, so dbexport becomes very useful.


> I would like to get some input on our backup/restore scheme.  First, I
> work in a production environment and do not have the option of testing
> our scheme.  We have several different UNIX (Solaris) systems running
> multiple instances of Informix 9.2xxx.  We are using raw space for our
> databases.  The disks are EMC and are mirrored using EMC software.  We
> use ontape to do a level 0 database backup nightly.  These are done to
> disks, which are then backed up to tape via UNIX.  Most of  the
> databases are not logged, but a logical log backup is performed daily
> on all.  We perform periodic dbschemas and store them on disk
> also.
> I guess my two main questions would be;
> 1) Is there anything that I should be doing that Im not? And
> 2) How would I restore in the event of a disk failure?  I understand
> the ontape -r, but Im not sure how to get to that
> point.  Would the dbspaces have to be created manually, before using
> the dbschema to recreate the tables, indexes, etc?

In order to restore Informix instance You must have new one with
exactly the same:
1) names of devices. Therefore it is beter if You access You raw
devices by links ( /chunks/onlinedevnr2m--->/dev/c1t3s4d4) because You
may always join link to other disk rather than change hardware disk
numbering convention (which is possible on some Unix sytems eg HPUX,
but it generates mistakes if is applied).
2) You must have the same name of the Informix server in onconfig, and
the same server number. Therefore succesful backup shold have Your
onconfig on tape, or maybe beter on paper ( printed).
3) If You want to have working application just before restore, You
have to have sqlhosts backup and of course configuration files for
applicatio.
3) You must have backup tape, which is consistent with data abowe.

Ussually  if You have dbexport it is more safer than output from
ontape because You may import it on any Informix ( and even not only
Informix) database server. But restor from dbexport takes more time,
and of course must be done for each database separatelly.
In IDS 7.x there are several bugs in dbimport which follow some
troubles with import ( You must divide Your schema into at least two
parts: data and stored procedures. procedures.sql must be imported
separatelly).
I don't know if there are similar bugs in neewer relases...

regards
KK

 
 
 

Backups/Restores

Post by Simmons, Keit » Fri, 19 Apr 2002 17:30:29


I would be very nervous of unlogged databases in a production environment.
You can only ever get back to your last level 0 archive (and if you have a
tape failure you might not even get to that point) and you will lose all
data changes since that point up to the point of failure (are your changes
re-runable outside of the engine?).
Dbschemas are *quite* useful for admin purposes, but of minimal (if any) use
in a restore situation.
To do a restore (of the entire instance using ontape) you need your onconfig
file in place, all the dbspaces set up and the environmental variable set
up. *ontape -r* will then restore the data. It first carries out a check to
ensure the dbspaces are available and of sufficient size, double checking
what you should already have.
Once the data is restored you will be given the opportunity to apply logs.
In you case this will apply any database/table structural changes (these are
always logged) but you won't have any data changes to apply.
Although you archive to disk you can restore from tape by changing the
onconfig file before restoring, however the logs need to be available from
the same source as the archive (the same disk file if restoring from disk or
the same tape drive (not necessarily the same tape) if restoring from tape).
Hope this is of help, please repost if there is any thing of which you are
unclear.

Keith Simmons
Banner Business Supplies Limited
Informix Certified Professional

-> -----Original Message-----


-> Sent: Wednesday, April 17, 2002 3:58 PM

-> Subject: Backups/Restores
->
->
-> I would like to get some input on our backup/restore scheme.
->  First, I
-> work in a production environment and do not have the option
-> of testing
-> our scheme.  We have several different UNIX (Solaris) systems running
-> multiple instances of Informix 9.2xxx.  We are using raw
-> space for our
-> databases.  The disks are EMC and are mirrored using EMC
-> software.  We
-> use ontape to do a level 0 database backup nightly.  These
-> are done to
-> disks, which are then backed up to tape via UNIX.  Most of  the
-> databases are not logged, but a logical log backup is performed daily
-> on all.  We perform periodic dbschema’s and store them on disk
-> also.
-> I guess my two main questions would be;
-> 1)        Is there anything that I should be doing that I’m not? And
-> 2)        How would I restore in the event of a disk failure?  I
-> understand
-> the “ontape -r”, but I’m not sure how to
-> get to that
-> point.  Would the dbspaces have to be created manually, before using
-> the dbschema to recreate the tables, indexes, etc?
->

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Backups/Restores

Post by Thomas Shann » Fri, 19 Apr 2002 22:58:55


Thanks for all of the responses.  It appears that dbexport is a
popular backup tool.  Anyone have more info on the "bug" in dbimport?
 
 
 

Backups/Restores

Post by Andrew Ham » Sat, 20 Apr 2002 11:26:30



>Thanks for all of the responses.  It appears that dbexport is
>a popular backup tool.

McDonalds is popular too, but that doesn't make it food.

Using the proper archiving tools (ontape or onbar) means you can take a
point-in-time snapshot on a live system, which integrates with the logical
log tapes. It's also got built-in technology to attempt to recover data from
damaged disks.

Using dbexport is a really poor alternative to doing it properly.
--
Windows: A 32 bit extension and graphical shell for a 16 bit patch to an 8
bit operating system, originally coded for a 4 bit microprocessor, written
by a 2 bit company which can't stand 1 bit of competition.

 
 
 

1. Synchronising databases by physical backup/restore and/Or Replication

Hi,

I have a question regarding synchronisation of SQL Server Databases.

I am using replication to synchronise the databases which may be
connected or disconnected.  I am using "Transactional Replication with
Queued Updating".
The above is working fine. Replication does happen when the databases
become online.
But I have a situation where I will need to copy the transactions from
the client on to a backup media and physically apply it against the
server (assuming all the time that replication is on).  This situation
can arise during extended periods of Network Non-availability and the
databases need to be synchronised.

Is there any way by which I can apply the transaction log backup from
the client on to the Server database and vice versa.  The
Server/Client database may be having an altogether different set of
data (data added during the time the client/Server were disconnected).

Please let me know if there is a way by which this issue can be
addressed.  Your answers to the above are highly appreciated.

Thanks

Raj

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