LD on large-cluster disk fails?

[Willem Grooters]

On my (8.2) system, one og the 18Gb disks is destined to hold logical disks as created by the LD utility (which is now built-in). Since these files tend to be 2-4Gb in size, I specified a clustersize of 80.
No big deal or OpenVMS, but for LD, it seems to be causing trouble. In creating a file of 2.000.000 blocks, it chokes the process that issued the LD command. I checked this process using SDA, found it didn't do a thing except LEF, with a channel to the disk busy.
Accessing that disk from another process, just DIR would do, will cause that process to stall as well. The first process is now in RWAST state.
After killing both processes after several minutes, there is no problem acessing the disk, where I find the specified file, but it's empty.

The same commans issued on a "normal" disk, with clustersize of 4, succeeds within seconds.

I couldn't find a clue on why access to the disk leads to hang the process - both LD and the other process.
All disks are controlled by the same HSZ50, on shared SCSI. None of them is a system disk, all are mounted /SYSTEM and usually accessable.

Is theer a limit in clustersize for LD to handle the CREATE command, or have I simply been too impatient?

[Volker Halle · Accepted solution]

Willem,

when creating the file, LD will probably erase the contents of the file - at least if high-water-marking is turned on on your disk. This is the same behaviour you see with SYSGEN> CREATE file/SIZE=big-number.

Recent versions of AUTOGEN include some specific tests for this situation and an appropriate help text.

Try again, but be more patient. The fact, that the 'hang' seems to have cleared up by itself, seems to support my theory.

Volker.

[Karl Rohwedder]

Willem,

I just compared creation of a LD container on a disk with a clustersize of 12 to another with 127. It makes no difference (both have high water marking enabled), perhaps this was different on your disks. Access to the disks is blocked as long as LD is working, which seems to support Volkers staement.

regards Kalle

[Jur van der Burg]

Willem,

LD does not do any black magic in this case, just a plain RMS Create. High water marking is probably on, and you won't see any i/o going on as that happens at DKdriver level. Just be patient...

Jur (LDdriver author).

[Willem Grooters]

Removed highwater marking - and problem gone.