Physical DBSpace is showing 0 bytes free
A user found that their dedicated physical-log dbspace (physdbs) had shown 0 bytes free for months, yet the server kept running fine, and asked why. John Miller explained this is normal: the physical log reserves a fixed block of space in the dbspace, so the dbspace legitimately shows as fully allocated. The physical log is a circular log that resets at each checkpoint; an oversized one merely wastes disk, while an undersized one hurts performance. The poster accepted the explanation; no action was needed.
Auto-generated by DrWatson from the posts below — may be imperfect; read the full thread.
This database server has been running for at least the last 8 months since we took it over showing the physical dbspace with 0 bytes free. What is happening under the hood to allow it to continue running without us adding space? DBSpaces number flags fchunk nchunks pgsize flags owner name 2 0x40001 2 1 2048 N B informix physdbs Chunks chunk/dbs offset size free bpages flags pathname 2 2 0 1024000 0 PO-BD /opt/informix/dbspaces1/physdbs
The physical log reserves a block of space in some dbspace. There are optimization & HA benefits if you actually use a dbspace marked as a physical log space, but that is optional. The physical log is just a circular log which resets at each checkpoint. Generally if the physical log is to big, not to many problems other than wasting some disk space, but if it is to small it can greatly effect performance. John F. Miller III miller3@us.ibm.com 503-747-1366 ids-bounces@iiug.org wrote on 04/14/2017 08:35:09 AM: > From: "BENJI LONG" <ruggedmouse@hotmail.com> > To: ids@iiug.org > Date: 04/14/2017 08:35 AM > Subject: Physical DBSpace is showing 0 bytes free [38933] > Sent by: ids-bounces@iiug.org > > This database server has been running for at least the last 8 monthssince we > took it over showing the physical dbspace with 0 bytes free. > > What is happening under the hood to allow it to continue running without us > adding space? > > DBSpaces > > number flags fchunk nchunks pgsize flags owner name > > 2 0x40001 2 1 2048 N B informix physdbs > > Chunks > > chunk/dbs offset size free bpages flags pathname > > 2 2 0 1024000 0 PO-BD /opt/informix/dbspaces1/physdbs > > > ***************************************************************************= **** > Forum Note: Use "Reply" to post a response in the discussion forum. >
Perfect, thanks John
Perfect, thanks John