Brick Level Backups
mcp6453
we're getting the "Top of Information Store" errors that appear to be
caused by Veritas Backup Exec. The problem is repeatedly attributed to
brick level backups, but like others who have gone before me, I don't
understand the mechanics of telling Exchange to to a DS/IS backup
instead of BLB. Please explain. Thanks!
Paul Hutchings
If you do a "basic" backup of the DS/IS you're effectively doing an "all or
nothing" backup, you can only restore the whole thing so if you need to get
back one mailbox, you have to get them all back.
If you do a brick level backup you're backing up individual mailboxes, so
in theory you can restore single mailboxes.
The downside is that with brick-level backups you typically lose all the
benfits of Single Instance Storage, so if you have ten mailboxes that each
have the same 100mb message in them, with a basic backup you're backing up
100mb, but with brick level you're backing up 10x100mb = 1gb.
If you follow the "Ed Crowley Never Restore Method" at
http://swinc.com/resource/exch_faq_appxb.htm you shouldn't ever need brick
level.
regards
Paul
--
paul <at> spamcop.net
mcp6453
Understood, and I read the article. However, I don't see where the
backup is in the method. It looks like the backups are being maintained
as part of Exchange instead of on a tape, which is not adequate if the
drive(s) fails. I confess to missing the point and would appreciate
further explanation.
Paul Hutchings
news:3DE056...@bellsouth.net:
>> If you follow the "Ed Crowley Never Restore Method" at
>> http://swinc.com/resource/exch_faq_appxb.htm you shouldn't ever need
>> brick level.
>
>
> Understood, and I read the article. However, I don't see where the
> backup is in the method. It looks like the backups are being
> maintained as part of Exchange instead of on a tape, which is not
> adequate if the drive(s) fails. I confess to missing the point and
> would appreciate further explanation.
>
You still need to do regular backups, but you should be able to do standard
backups rather than brick-level as using the Ed Crowley method you should
never be asked to restore a folder or a message or a mailbox - unless you
screw up and delete a mailbox.
I'm not an expert but if you have enough time and space to do brick level
backups I guess there's no harm done, but all the Exchange disaster
recovery papers (that I've read) seem to base things on a standard backup.
Melissa Travers [MS]
Microsoft does not support brick level backups. However we realize that our
customers do these types of backups for various reasons. But in the event
of a database failure a full backup of the Exchange databases is
recommended. There have been problems associated with restoring from Brick
level backups such as missing calendar and contact items or strange things
such as a phamtom duplicate calendar folder that cannot be deleted.
So as a best practice you should do database backups for your private and
public stores and if you wish to do brick level backups, for whatever
reason, continue to do so as long as you have the database backups up as
well.
Hope this is helpful
--
Melissa Travers, MCSE
Microsoft Exchange Support
Please do not send email directly to this alias. This alias is for newsgroup
purposes only.
This posting is provided "AS IS" with no warranties, and confers no rights.
"mcp6453" <mcp...@bellsouth.net> wrote in message
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John Francis Burke
During an online backup, each database page is read, the checksum verified,
and then written to tape (or wherever).
In order to preserve database integrity :
1. Each page is locked whilst it is read to prevent transactions being
applied to it.
2. Transactions that would normally have been applied to pages that are
already backed up are placed in .pat files
3. At the end of the backup, the .pat files are written to tape.
4. Transactions may subsequently be applied as normal.
When the backup is restored, the pages are read from tape to form the
database and then the .pat files are restored and replayed against it.
Verifying the checksum is a first line defence against inconsistencies
caused by hardware failure, allowing you to recover using yesterday's
backup.
(If any of that is wrong, please correct me :-)
John Francis Burke, MCSE
"mcp6453" <mcp...@bellsouth.net> wrote in message
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mcp6453
I understand your response, but not being an Exchange guru, I don't know
how to accomplish the specific steps you suggest to "do database backups
for your private and public stores." I *still* do not understand the
difference between what you suggest and brick-level backups.
Mike
Ben Winzenz
detail.
A "database" backup is a normal, online backup of just that, the information
store. Directly out of the BackupExec Administrator manual:
"Backing Up Exchange Server
To back up Microsoft Exchange Server:
1. From the Backup Selections tab in the Backup Exec main window, click
Remote
Selections, then click Microsoft Windows Network, or click Local Selections
if the
Exchange databases or storage groups are local.
2. Click the domain containing the Microsoft Exchange server you want to
back up.
A list of Windows NT/2000 computers appears.
3. Click the Windows NT/2000 computer containing Microsoft Exchange Server.
Note If you are using a server cluster, make backup selections from the
virtual server.
A list of shares appears along with Exchange database or storage group
icons, and
mailbox icons.
4. Select the databases or storage groups you want to back up."
You should have as selections,
1. Microsoft Exchange Directory
2. Microsoft Exchange Information Store
3. Microsoft Exchange Mailboxes.
IF you ONLY choose the Directory and Information Store, you are performing
an Online, Full Backup of the DATABASES. The databases being priv.edb and
pub.edb (theses are the actual files). IF you select Microsoft Exchange
Mailboxes, you are doing a Brick-Level backup, or Mailbox level backup.
What you are doing with a brick-level backup is logging on to the Exchange
server with a MAPI profile and accessing EACH and EVERY mailbox and
basically copying the contents of the mailbox to the backup medium. Here is
another snippet from the BE admin manual:
"When you select the Information Store and Directory Store databases for
backup, mailboxes and messages are included in the backup. However, you can
also select one or more messages, mailboxes, or folders for backup without
selecting the databases.
Caution!!! Generally, mailboxes should not be backed up separately from the
databases
until you can run a test (based on your environment) to determine that
system
performance does not deteriorate. You should expect mailbox backups to take
longer than database backups.
In addition, backing up individual mailboxes should not be used as a
substitute for backups of the entire Information Store database. For full
recovery of an Exchange Server, you must back up and restore from
Information Store database backups. This applies to both Exchange 5.5 and
Exchange 2000."
--
Ben Winzenz
Network Engineer
Gardner & White
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