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HP OpenVMS Systemsask the wizard |
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The Question is: What does the "Trans Count" column on a $SHOW DEVICE <disk> mean? I had always thought it meant the number of open files on the disk. I now have a Trans Count of 2765 but a $SHOW DEV/FILE only shows 7 open files + INDEXF.SYS. Also, from SDA it doesn't seem to be the number of channels from any of the seven processes with one file open each. Thanks, Colin Shaw. The Answer is : The SHOW DEVICE "trans count" (transaction count) is the number of File Control Blocks (FCBs) associated with the device, and this includes the number of files open on the disk, particularly including any extension headers that might be present. Please also ensure that you have the current mandatory ECO kits installed on the system for the OpenVMS release in use, and please move to a supported release -- there is the potential that this large transaction count is artificially large, and was caused by a (benign) problem within the file system that was found and fixed in 1999. Please also ensure that your disks are not excessively fragmented, as this will increase the numbers of extension headers required for mapping the files. A search engine that can provide you with lists of ECO kits based on the ECO installation ratings is referenced in the OpenVMS FAQ. Please get and please apply all mandatory kits. As of this writing, OpenVMS V7.2-2 or V7.3-1 would be the logical upgrade paths for this system. Continuing with the SHOW DEVICE discussion, the SHOW DEVICE "mnt cnt" (mount count) shows the number of times that a volume has been mounted, both locally and throughout the cluster. Shared disk volumes can be mounted multiple times on one node, or across multiple cluster members. Batch jobs can use a MOUNT command to effectively prevent an existing and previously-mounted disk volume from being dismounted until the batch job is completed, for instance. There is no user interface to the SHOW DEVICE mount count field; the value is retrieved from an internal data structure. The sys$getdvi (and f$getdvi) MOUNTCNT item returns the node-local mount count; the number of times the volume is mounted on the local node.
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