Operating OnLine 3-107

Change Physical Log Location or Size

To start or end mirroring
1. Select the Dbspaces menu, Mirror option.
Every OnLine blobspace and dbspace is listed. You can start mirror-
ing for spaces with a status ofN . You can end mirroring for spaces
with a status of Y.
2. Use the RETURN key or the arrow keys to select a blobspace or
dbspace. PressCTRL-B or F3.
Ifthe current status is Y,DB-Monitor ends mirroring and releases the
mirror chunks.
If the current status isN,DB-Monitor prompts you for the full path-
name location, offset, and size of each mirror chunk.
Informix recommends that you use a linked pathname. (Refer to
page 1-22 for further information about the benefits of using linked
pathnames. Refer topage 1-43 for guidelines on how to determine
where your chunks should be located on disk.)
3. Specify an offset in theOffset field if it is appropriate for your
device. (Refer topage 1-49 for further information about how to
determine if you need an offset.)
4. Enter the size of the chunk, in kilobytes, in theSize field.
Change Physical Log Location or Size
Thesize of the physical log is specified as PHYSFILE in the configuration file.
The dbspace location of the physical log is specified as PHYSDBS.
You can move the physical log file to try to improve performance. When
OnLine disk space is initialized, the disk pages allocated for the logical log
and the physical log are always located in the root dbspace. After OnLine is
initialized, you might be able to improve performance by physically
separatingthe physical log and the logical log and placing them on disks that
are not shared by active tables.
Thespace allocated for the physical log must be contiguous. If you move the
log to a dbspace without adequate contiguous space or increase the log size
beyond the available contiguous space, a fatal shared-memory error occurs
when you attempt to reinitialize shared memory with the new values.
Specify the size of the physical log in kilobytes.