[Info-vax] Re; Spiralog, RMS Journaling (was Re: FREESPADRIFT)

[David Froble]

Michael Moroney wrote:
> lawrencedo99 at gmail.com writes:
> 
>> On Saturday, June 18, 2016 at 2:26:45 AM UTC+12, Stephen Hoffman wrote:
> 
>> Then where is the inconsistency in free-space usage coming from? You 
>> know, the issue that started this thread?
> 
> I can't tell for certain without more info, but in a cluster wide mount,
> some stuff like file headers and disk space bitmaps are allocated to each
> cluster member (and marked as allocated on the disk) so the cluster member
> can create/extend files without all the inter-cluster traffic required to
> update cluster members every time this happens.  When a disk is properly
> dismounted, unused allocated space is returned.  If a cluster member
> crashes, it is possible for other members to not be able to mark space
> allocated to the departed member free, it remains as a ghost allocation.  
> MOUNT/REBUILD normally clears this stuff up.

Hmmm ....  perhaps this explains why I never see such problems on my 
non-clustered systems?