topic Re: SET VOL/REBUILD=FORCE Explanation in Operating System - OpenVMS

SET VOL/REBUILD=FORCE Explanation

Jack Trachtman — Thu, 22 Sep 2005 12:06:38 GMT

Below is the Help text. Could someone provide more explanation of the FORCE option vs not uisng FORCE? Thank you

SET

VOLUME

/REBUILD

/REBUILD[=FORCE]

Recovers caching limits for a volume that was dismounted
improperly. If a disk volume was dismounted improperly (such
as during a system failure), and was then remounted with the
MOUNT/NOREBUILD command, you can use SET VOLUME/REBUILD to
recover the caching that was in effect at the time of the
dismount. The FORCE option forces the disk to be rebuilt
unconditionally, thus updating the free block count in the disk
volume's lock value block.

Re: SET VOL/REBUILD=FORCE Explanation

Jan van den Ende — Thu, 22 Sep 2005 12:18:11 GMT

Jack,

since the option is default, and as far as I can see non-negatable, I take it that is documentary only.
Maybe some time in the past Engeneering thought it wise to leave open the option for future devellopments?

Are there any REAL gurus around that can confirm this, or explain otherwise?

Proost.

Have one on me.

jpe

Re: SET VOL/REBUILD=FORCE Explanation

Uwe Zessin — Thu, 22 Sep 2005 12:25:57 GMT

If I recall correctly, the history is this:

SET VOLUME/REBUILD (without FORCE) used/uses some characteristics of the volume to find out if a rebuild was really necessary - sometimes the assumption was wrong and the disk was not rebuild. FORCE will tell the code to skip these checks and always run a full rebuild.

Re: SET VOL/REBUILD=FORCE Explanation

Jack Trachtman — Thu, 22 Sep 2005 13:08:35 GMT

Addiontal question:

This command is supposedly safe to run at any time, and I presume it could run for a few minutes on a disk with lots of files.

Does it lock the disk during its work, therefor the users might see a "pause"?

Re: SET VOL/REBUILD=FORCE Explanation

Uwe Zessin — Thu, 22 Sep 2005 13:24:09 GMT

Yes, it must lock out de/allocation changes to get a consistent view while it walks through the file headers, although reading/writing of existing files might be allowed (I'm not sure).

Re: SET VOL/REBUILD=FORCE Explanation

Ian McKerracher_1 — Thu, 22 Sep 2005 14:24:13 GMT

Hello Jack,

You may find this of interest:

http://h18000.www1.hp.com/support/asktima/operating_systems/CHAMP_SRC980303000978.html

And now a piece of trivia - the /REBUILD qualifier for SET VOLUME was introduced in V5.5.

Regards,

Ian

Re: SET VOL/REBUILD=FORCE Explanation

Jack Trachtman — Thu, 22 Sep 2005 15:38:47 GMT

Thanks all