1. you need an Exchange Server at the W2K level (Exchange 2000)
2. I dont now if IBM / Tivoli already have build the new API for the Brick
Level Restore.
Steve Strutt@TIVOLI SYSTEMS
18/02/2000 09:23 AM
To: Steve Cliff/Tivoli Systems@TIVOLI SYSTEMS@IBMUS
cc:
Subject: TSM and Exchange Brick-level backup
Steve, you may want to forward this to the EMEA TSM group. I had to put
together the latest position for a business partner.
This is the current position of Tivoli Storage Manager as regards the
requirement for 'brick-level' backup in Microsoft Exchange.
Brick level backup has a number of limitations which limit it usefulness as
a general purpose backup capability. In Exchange 5.5 Microsoft provide an
'item recovery' facility which allows the recovery of deleted mail items
for a specified grace period which meets most of the requirements for mail
box restore. Microsoft intend to extend this capability in Exchange 2000
to provide full mailbox recovery. The Tivoli Data Protection agent for
Exchange 2000 is intended to be shipped in 4th quarter 2000 and this will
exploit the features implemented by Microsoft in Exchange 2000. The
following notes give more details of of the issues with brick-level backup
and the enhancements to Exchange 2000.
Brick Level Backup
In order to offer mailbox or individual msg restore granularity, non backup
APIs (called MAPI) must be used to back up the exchange data at that
granularity. Tivoli Storage Manager has chosen not to use MAPI for backup
and recovery because there are several issues associated with their use.
The two most significant ones are:
1. poor performance and scalability, when compared to throughput possible
when using the backup APIs.
2. breakage of the single object store architecture in Exchange.
The following example illustrates the issue relating to the second point :
When a mail message is sent to a distribution list of 20 people, that mail
item is stored in Exchange only once and each of the 20 mailboxes has a
pointer to the single instance of the item. When MAPI interfaces are used
to extract the mail items for mailbox level backup, then the full mail item
is extracted repeatedly for each mailbox. This means that the size of the
backup data when stored per mailbox could be much larger than the actual
size of the IS. Further, when restoring by individual mailbox, the mail
object will be stored multiple times so that the resulting IS will be
larger than the original...and may even cause issues with being able to fit
on available storage (especially if large attachments are included in mail
sent to multiple people).
Microsoft recommends against using MAPI for backup and recovery. During
last fall's Exchange conference in Atlanta, Microsoft once again reiterated
that MAPI should not be used for that purpose. To address the issue of
simple recovery of an individual mail item, Microsoft has provided the
"item recovery"
feature in Exchange 5.5 and has indicated that it will provide the
additional feature of "Mailbox recovery" in Exchange 2000 which is expected
to become available mid 2000 (this was demoed at the conference). Both of
these features provide a grace period for which deleted items will remain
in the IS before they are actually purged. Thus, if a mail item or entire
mailbox is accidentally deleted, during the grace period, it will be
possible to recover it through an exchange or outlook client without any
need to access the backup storage. The grace period for this capability
can be set by the Exchange administrator.
Additionally Exchange 2000 will be providing some significant architectural
changes (multiple storage groups (up to 15) with up to 6 db files per
storage group) which will enhance the manageability and scalability of
exchange servers. The IS will be subdivided into more granular parts so
that backup and recovery can be done at a more granular level than today
(with parallel sessions at the storage group level). TSM development is
focusing on exploiting the new Exchange 2000 features as that will offer
relief for managing large Exchange server environments in a manner
consistent with the Microsoft Exchange backup architecture. These offering
improved backup and recovery times and greater granularity in recovery,
which will scale with the growth in Exchange and the size and volume of
email traffic.
with kind regards
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Joachim Paul Schaub
Abraxas Informatik AG
Beckenhofstrasse 23
CH-8090 Zürich
Schweiz / Switzerland
Telefon: +41 (01) 259 34 41
Telefax: +41 (01) 259 42 82
E-Mail: mailto:joachim.schaub AT abraxas DOT ch
Internet: http://www.abraxas.ch
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