There is a new flash for TSM.
http://www.tivoli.com/support/storage_mgr/flash_tsmultrium.html
Who: Customers using Windows 2000 and IBM Ultrium tape drives with Tivoli
Storage Manager (TSM) V4.1 and V4.2 lanfree or library sharing functions.
If you are not using Windows 2000 and IBM Ultrium tape drives with Tivoli
Storage Manager (TSM) V.4.1 and V4.2 lanfree or library sharing functions
you are not affected.
Attention: We have identified an exposure in environments where IBM
Ultrium tape drives are being shared with multiple Windows 2000 hosts
which use TSM library sharing function or the lanfree function. During
some situations, more than one host may concurrently use the same tape
drive resulting in data corruption.
Specifically, you are exposed to this problem if:
- you are using at least two Windows 2000 systems and a TSM server or
a TSM storage agent on each system
- these systems share one or more IBM Ultrium tape drives between them
- a change occurs in your SAN network where hardware is added to the
SAN, removed from the SAN, or fails.
Problem Description: When hardware is added to, removed from, or fails on
a SAN network, the plug and play capability of Windows 2000 is
automatically invoked by the operating system. This may cause the devices
to be mapped differently than they were previously while applications are
active. In some circumstances when a remapping occurs, a single Ultrium
drive may be accessed by more than one Windows 2000 host simultaneously
causing data corruption.
Immediate Action: If you are using the lanfree function of TSM, you
should disable it and return to LAN backup until a circumvention is
provided. To disable the function, remove the ENABLELANFREE statement
from the TSM client options file and ensure that the COMMMETHOD is
appropriately set to communicate with the TSM server over the LAN.
If you are using the library sharing function of TSM, it is unlikely that
you can disable this function as it would require additional Ultrium drives
and libraries for the TSM library client. Therefore, take the following
precautions until a circumvention is available:
Do not allow the TSM servers on Windows 2000 to autostart at reboot
Do not allow the TSM storage agent on a Windows 2000 machine to autostart
at reboot
When a Windows 2000 system is restarted, ensure the mapping of the
devices is correct
Do not add or remove equipment in your SAN until a circumvention is
available. If you must add or remove equipment, ensure that you have halted
the Windows 2000 machines running TSM servers and storage agents and
checked the drive mappings before restarting the servers and storage agents
If a hardware failure occurs and the device is no longer visible to a
Windows 2000 system, immediately stop TSM processing until you are sure
that the devices are properly mapped on the Windows 2000 system
Check to ensure that you have enabled all remapping capabilities
available with your adapter. For example, Emulex provides a parameter
which attempts to map hardware on a Windows 2000 system in a persistent
manner through reboots. Qlogic provides an application called QLCONFIG
which also attempts to retain remapping done by Windows 2000. Enabling
these hardware functions will minimize but not entirely remove your
exposure to this problem.
-- Regardless of which adapter you are using, you should review the
mapping on Windows 2000 systems running TSM library sharing or lanfree
mapping on Windows 2000 systems running TSM library sharing or lanfree
functions after a reboot to ensure that they correctly point to the drives.
You should also review the mapping when hardware problems have occurred in
your network.
Temporary Intervention: Tivoli Storage Manager V4.2 will provide a
temporary patch to use the TSM device driver where code has been added to
temporarily circumvent the problem. This temporary circumvention is
documented in APAR IC31822. An enhancement to the IBM Tape device driver
will be made available via anonymous ftp from ftp.software.ibm.com, file
/devdrvr/Win2000/IBMUltrium.5.0.2.3.exebin. This enhancement will ensure
that a SCSI RESERVE is issued whenever the drive is opened from one Windows
2000 host, which will prevent any other host from accessing the drive.
Explanatory information concerning the enhancement will be available in
files /devdrvr/Win2000/IBMUltrium.fixlist.txt and
devdrvr/Win2000/IBMUltrium.Win2k.Readme.txt
On Tivoli Storage Manager 4.1, there is no interim circumvention other than
limiting your exposure to the problem by taking the precautionary steps
listed above. When the enhancement is available via level 5.0.2.3 of the
IBM device driver, you will need to use that level of the driver.
______________________________________________________________________________________________________________
Questions and Answers
1) Am I impacted if I use other IBM devices such as the IBM 3590 or 3570?
No -- In TSM, on Windows 2000, only the IBM Ultrium tape drive uses the
IBM Tape device driver. Therefore, other IBM devices used by TSM are
not affected.
2) Does this happen with only IBM Ultrium Tape drives attached via the IBM
San Data Gateway (rather than direct fibre attached)?
No. It occurs with both direct fibre attached IBM Ultrium tape drives
and those attached through the IBM San Data Gateway.
3) If I am not using the library sharing or lanfree features of TSM am I
affected?
No. You are only affected if you are using the library sharing or
lanfree features of TSM. You must have more than one Windows 2000
system attempting to share at least one IBM Ultrium tape drive to be
affected.
4) If I only have one Windows 2000 system sharing with other non Windows
2000 systems (such as AIX or SUN) am I affected?
No. You must have at least two Windows 2000 systems. In the case of
drive sharing (and remapping) between a Windows 2000 system and another
non-Windows 2000 system, a SCSI reservation applied to the drive from
the non-Windows 2000 system will prohibit the Windows 2000 system from
mistakenly accessing the drive. Note that the Windows 2000 process will
fail, but data will not be corrupted.
5) If I am using Windows NT instead of Windows 2000 am I affected?
No. You are only affected if you are using Windows 2000. NT device
driver does do a reserve/release.
6) If I am using a non IBM Ultrium device am I affected?
No. You are only affected if you are using an IBM Ultrium tape drive.
7) My SAN network is very stable. I never add or remove devices to my
network. Am I affected?
Yes. Even though you may not be adding or removing hardware, if
hardware fails on your network, it may "disappears" from Windows 2000
as if it were removed. This causes the remapping of devices to
automatically occur in Windows 2000.
8) My Windows 2000 systems are never rebooted. Am I affected?
Yes. Because Windows 2000 has plug and play capability, it sees
hardware appear and disappear without going through a reboot. Anything
causing hardware to appear or disappear to a Windows 2000 system will
trigger the remapping function of Windows 2000. Because Windows 2000
does not store information about devices in a database and instead
derives the "name" each time a change occurs, this problem exists.
9) I am not using the RSM function of Windows 2000. Am I affected?
Yes. The RSM function of Windows has no impact on this problem.
Regardless of whether you are using this feature, you are exposed to the
problem if your installation meets the criteria described in the flash.
10) I used library sharing on TSM 3.7. Am I affected?
No. TSM did not support the 3581, 3583, and 3584 until TSM 4.1 on W2k.
These libraries would be necessary to support the library sharing or
lanfree function of TSM with the IBM Ultrium tape drive. TSM did
support this libraries on 3.7 with NT, but NT does not have the problem.
(The Windows 2000 solution with LTO required RSM which is not available
on 3.7)
James Thompson
Performance Analyst - Open Systems
Tivoli Certified Consultant - TSM 4.1
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