Microsoft provides a backup software solution with the
Windows NTBackup software. Most Enterprise customers choose to use more robust
enterprise-oriented backup software and hardware solutions. However, in
choosing that solution, customers who use Windows server clusters have to
recognize special considerations that apply to these servers. This article
describes these considerations.
Considerations for cluster backup software include the
- Cluster backup software should be "cluster aware" because
it uses cluster APIs and can gracefully deal with the failover of a disk
resource during the backup process.
- While we do not recommend open file managers for use on a
cluster, if any are installed they have to gracefully handle a failover of a
disk resource and correctly release all handles to the disk. Failure to release
open handles may cause the disk to appear to the receiving node to have the
dirty bit set and will trigger a chkdsk /f on that disk resource.
Other considerations include the following:
- The hardware and storage area network (SAN) fabric must be
architected in such a way that tape devices do not share the same small
computer system interface (SCSI) bus or host bus adaptors (HBAs) as the shared
storage disks. For Fibre Channel, some vendors try to interpret bus resets into
other Link Services commands, assuming the bus reset is only used to clear
reservations and is issued by clusters only. In fact, bus resets are used
within the Windows storage stack for recovering from command timeouts. If the
command timeout was on the tape drive, and the reset is translated to a
different Link Services command, the tape drive is likely not to recover and
will not be available for use unless its power was cycled or the system was
Note The power being cycled could lead to other failures because some
backup applications cannot correctly process the PnP notifications that will
We do not recommend such a configuration with SCSI miniport
or a monolithic full-port driver.
Some storage vendors may offer their
own solutions for coexistence of disk and tape on a single HBA with either a
SCSIport miniport driver or a monolithic full-port driver. Support of these
types of solutions is the responsibility of the storage vendor and not
Microsoft, and the storage vendor must be the first point of contact for any
disk related issues in these configurations. Microsoft supports the use of disk
and tape on the same HBA using Storport miniport drivers.
recommends use of Storport, a new port driver, which is available for use in
Windows Server 2003 for the above mentioned configuration. In the Storport
environment, Windows will use LUN and target resets to clear reservations and
timeout problems. This prevents a reset of devices that are not involved in the
error condition. Cluster configurations based on the Storport driver that share
tape and disk on the same HBA or SCSI bus can be supported by Microsoft.
- Software that installs filter drivers, such as antivirus
software or multipathing software, must be "cluster aware" and must be able to
gracefully let the disk resource to failover to other nodes.
- Some backup solutions use what is known as "server-less"
backups. These solutions cannot be used with a server cluster because of the
cluster's persistent binding to the HBA. Server-less backups must be performed
to a mirror set which is implemented in the hardware of the SAN and does not
involve the cluster software. All backup solutions that are implemented outside
the server cluster's fabric are the support responsibility of the backup vendor
and not Microsoft.
For additional information about Windows server clusters, visit
the following Microsoft Web sites:
For additional information, click the following article
number to view the article in the Microsoft Knowledge Base:
CHKDSK may be initiated if there are open handles when a cluster disk fails over
How to properly restore cluster information
The Microsoft support policy for server clusters, the Hardware Compatibility List, and the Windows Server Catalog
Antivirus software may cause problems with cluster services
Article ID: 887017 - Last Review: February 8, 2007 - Revision: 2.6
- Microsoft Windows 2000 Advanced Server
- Microsoft Windows Server 2003, Standard Edition (32-bit x86)
|kbwhitepaper kb3rdparty kbclustering kbhowto kbinfo KB887017|