Technical data

System Management Release Notes

5.9 OpenVMS Cluster Systems

Table 5–2 System Parameter Settings for Multipath Shadow Sets

System Parameter Recommended Setting

MSCP_CMD_TMO 60 as a minimum.

The value of 60 is appropriate for most conﬁgurations. Some

conﬁgurations may require a higher setting.

SHADOW_MBR_TMO 3 x MSCP_CMD_TMO

SHADOW_SYS_TMO 3 x MSCP_CMD_TMO

MVTIMEOUT At least 2 x SHADOW_MBR_TMO

The following example shows the use of the recommended settings:

MSCP_CMD_TMO 60

SHADOW_MBR_TMO 180

SHADOW_SYS_TMO 180

MVTIMEOUT 1200

5.9.15 Multipath Devices: Volume Rebuilds During Mount Operation

V7.2-1

When mounting a Fibre Channel or SCSI device, a volume rebuild is sometimes

performed even though the volume was previously dismounted without any

apparent error. For example:

$ DISMOUNT $1$DGA32762:

$ MOUNT/CLUSTER $1$DGA32762: MYVOL

%MOUNT-I-MOUNTED, DGA1016 mounted on _$1$DGA32762: (FIBRE2)

%MOUNT-I-REBUILD, volume was improperly dismounted; rebuild in progress

Workaround

A user with privileges can work around this problem by issuing an I/O to the

device immediately before dismounting it. For example:

$ CREATE $1$DGA32762:[0,0]A.TMP

$ DELETE $1$DGA32762:[0,0]A.TMP;0

5.9.16 Multipath Device Dismount Problem with Volume Shadowing

V7.3

If a multipath member of a shadow set switched paths prior to being dismounted,

and no I/Os were issued immediately before the DISMOUNT command was

issued, the dismount fails and the following error message is displayed:

%DISM-W-CANNOTDMT

This error does not occur under the following conditions:

• If no path switch occurred before the use of the DISMOUNT command.

• If a path switch did occur, I/O was issued to the device before the use of the

DISMOUNT command.

A user with privileges can work around this problem by issuing an I/O to the

device immediately before dismounting it. For example:

$ CREATE $1$DGA32762:[0,0]A.TMP

$ DELETE $1$DGA32762:[0,0]A.TMP;0

5–20 System Management Release Notes