Support News Flash

Support News Flash for 2001

April 19, 2001 - DATABASE EXPANSION PROBLEM WITH ALL MSM 4.4.x VERSIONS

A problem was discovered in the database expansion patch DB40FIX.zip, which fixes critical database expansion problems with all MSM 4.4.x systems. A new patch kit called DBFIX0104.ZIP has been created that should be loaded on all existing MSM 4.4.x systems. The patch is available on the InterSystems public ftp server at ftp://ftp.intersys.com/pub/msm/patches/DBFIX0104.ZIP. The problems resolved by this new patch kit are described below.

Two problems involve adding database volumes to an existing volume group. First, if the file name of the volume being created was longer than 64 characters, it was not handled properly, leading to errors during creation and mounting (PR012729). The second, and more significant issue resulted in <DKHER> errors in the newly created volume. In addition, in some cases, one block in an existing volume could be corrupted (PR012765).

The third occurred if the "SysAdmin" tool (an unsupported tool) was used to expand a volume group with BIJ enabled, the expand would work, but a <NOPGM> error would occur at the end, and BIJ would be disabled (PR012785).

The fourth occurs if more than one additional volume was added to an existing volume group without dismounting and remounting it. The self-identifier (an internal structure) of the label block of the first unmounted volume would be reset to zero. The error would not be immediately apparent unless you added more then two additional volumes. However, at some point in the future the system would attempt to access the label and you would receive a "<DKSER>:::7:35:" error on the label. (CCM053M)

As part of the patch for CCM053M a new routine named VGLABCHK has been added, it will check a volume group's labels for consistence in a number of ways, including the labels self-identifier. It is recommended that you run this utility on all volume groups if you suspect that you may have any of the problems listed above. (CCM043M)

We strongly recommend that this patch be installed on ALL MSM Version 4.4.x systems, even if you have previously installed database expansion patches. You may also want to use the ^VGLABCHK utility to ensure that all your existing labels are correct.

If you have any questions InterSystems Worldwide Response Center (WRC) at 617.621.0700 or support@intersys.com.

April 2, 2001 - MSM - Daylight Savings Time Problem

MSM has been found to be affected by a bug in Microsoft Visual C++ which affects the way that daylight savings time is calculated during years when April 1 falls on a Sunday. The problem is seen in MSM as the MSM time being one hour behind the system time - essentially still reporting EST instead of EDT. This bug only affects the first week of April, starting April 8 MSM and Windows time will be in synch again. This problem is present for all supported MSM 4.x releases under both Alpha and Intel flavors of NT as well as Windows-95/98 (the MSM for Windows-NT and MSM for Windows-95 products).

As a workaround for this problem InterSystems WRC suggests disabling the automatic daylight savings time adjustment of Windows. This can be done through the Windows control panel.

In Control Panel => Date/Time => Time Zone tab, uncheck the "Automatically adjust clock for daylight saving changes" box, and click apply.

Then under Control Panel => Date/Time, manually correct the time and click apply.

If you have any questions InterSystems Worldwide Response Center (WRC) at 617.621.0700 or support@intersys.com.

January 9, 2001 - MSM Database Expansion Beyond 2 Gigabytes can Corrupt or Destroy a Database

*** This can delete existing data on a volume expansion ***
On all currently supported releases of MSM there is an issue when creating or expanding a database beyond two gigabytes (4096 maps, 2,097,152 kilobytes or blocks, 2,147,483,648 bytes). We have only seen the problem on UNIX, but it may also occur on Windows-NT, and Windows-95/8 using FAT16 file systems. On some implementations of UNIX when you reach 1 UNIX block (512 bytes) before the two gigabyte boundary MSM ceases to be able to expand the file further (although there is no error), as a result the database is rendered unusable. In other cases at the two gigabyte boundary MSM begins writing the newly formatted blocks at the beginning of the volume file, or at some other location within the existing database. Destroying the file and deleting any existing data in the volume. This appears to be an integer overflow problem at the UNIX level, and can express itself differently on differently on different versions of the same operating system.

In the next released version of MSM you will not be allowed to create or expand a single volume of a group past two gigabytes minus 4 kilobytes (2,093,056 blocks/kilobytes or 4088 maps). The reason for setting the limit to this size is because we want to avoid meeting the two gigabyte boundary, and MSM volume groups maximum size must be evenly divisible by 4meg.

Until the next release you must not expand or create volumes larger than this. Be aware that this will not significantly reduce the maximum size of a volume group, but it will require that the volume group be made up of 8 volumes.

It should also be noted that we have seen similar issues creating or reading HFS (device 51 - 54) files as well, you should also avoid accessing these large files from MSM.

Versions affected: MSM-UNIX v4.3.(all minor releases and patch levels), 4.4.0(all patch levels), 4.4.1(all ad-hoc releases). It is likely to effect some other older versions, and may effect non-UNIX products on operating systems or file systems that have not traditionally supported large file systems.

If you have any questions InterSystems Worldwide Response Center at 617.621.0600 or support@intersys.com.

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