As announced 2 weeks ago we did some research on backing up MS-SQL and
Exchange Servers using ADSM.
There's an 3 methods for doing the necessary backup:
1. You can shutdown the database, start the backup, wait for completion
and restart your database. The method is easy and reliable, but you
can't have the database online 24 hours per day.
2. At least with the SQL-Server you can produce a fulldump of the
database while the server is running and then backup this file normally
like any other file. It works, but keep in mind that you will need twice
the ammount of storage space the database usually consumes as the
created file is written to your harddisk. So it is a good way to use the
method for small environments, but it is unusable for larger databases.
3. You can use a database agent that communicates directly with both the
database and the ADSM server.
One product that implements the 3rd method is BackupExec from Seagate.
Before I give a short description of our experience with the product,
here are the basics on how it works:
SQL/Exchange <=> {BackupExecAgent <=> BackupExec (single server) <=>
ADSM Option} <=> ADSM-Server
The ADSM Option emulates a huge autochanger backupdevice with a virtual
magazine. The magazine holds as many virtual medias as you want and each
media can contain more than 2 TB of data.
Seen from the client side the Exchange (SQL) server is backed up simply
using BackupExec. Only the backup device driver does not write to a
local drive but connects to the ADSM server.
You need licences for the products in "{"-brackets, note that you don't
need the autochanger option of BackupExec (as one might expect).
Our tests
Installation:
Installation of BackupExec is no problem, I first tried to backup to a
real tape drive which worked as expected. To get backups of the Exchange
server working, I needed some help from our MS-Backoffice specialists.
Unfortunately BackupExec creates one LOCAL account to be used for backup
purposes, grants all necessary rights to this account to do all usual
backups, but you need a domain account to perform Exchange backups. I
think it is also possible with a local account on some implementations
of Exchange, but one of our specialists said that it's not conforming to
Microsoft's rules for Exchange implementations.
For using the ADSM option it is necessary to first run a special script
on the ADSM server to prepare a special policy domain, backup group...
An extra diskbased storage pool without migration is created for the
database holding information on virtual magazine contents, BackupExec
does not use the ADSM database.
Seagate does not provide any information on other ADSM-servers than
WINNT, but we "translated" the script for use with MVS (and preallocated
and formatted the space for the storage pool) and the whole complex
worked from the first try.
Using the product to backup:
Very positive: BackupExec creates no additive bottlenecks. All actions
that usually move tapes or read indexes are really fast. Initialization
of BackupExec can take some time, but try to catalog a virtual tape -
really fast.
The backup process was as fast as network permitted, that looked good
but I can't say anything about the maximum possible speed of the whole
combination as our network is an obvious bottleneck...
Restore under non-disaster circumstances:
You can use all BackupExec features with the ADSM option, too. I deleted
documents in the Exchange database and brought all of them back without
problems.
Restore in case of disaster:
We formatted the harddisk of our testserver and restored all files using
ADSM. System was running again, only the databases did not start as the
excluded open files were not available. BackupExec brought back all the
databases and I did not find any problems after a server reboot.
==>
All features worked great with our testserver, there are some places
where Seagate could do it better. A new version of BackupExec is
announced for September 15th, I think we'll try this version before
installing the product on our large servers. Especially the possibility
to start a backup from outside BE (using a batch or the ADSM scheduler)
is missing up to now.
And I don't know if all our tests can be reproduced on a larger
environment. I don't want to implement the backup method on our large
servers prior to having tried to restore a server with a comparable
amount of data.
IBM also announced agents for SQL and Exchange for next year. It depends
on the quality of these products, I think direct ADSM support could be
better than putting a number of products into a row.
Does anyone have information about other possibilities to backup SQL and
Exchange databases?
Regards,
Michael
--
Michael H. Bartl
Michael H. Bartl
ADAC e.V. (Rechenzentrum, Produktionsplanung und Organisation)
Tel.: (089) 7676-4063, Fax: (089) 7676-8161
EMail: Michael.Bartl AT Zentrale.ADAC DOT de
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