FUJITSU CentricStor V3.1D - Manual (Page 252)

252 U41117-J-Z125-7-76
Display of the Global Status Monitor Global Status
Virtual library servers
The middle column indicates the operating statuses of the VLM and virtual library servers
(VLSs).
If you click the left mouse button on on an object, an info box is output containing further
details. In the case of control components, for example, this would indicate the host on
which the component runs.
Tape volume caches
The display of the tape volume cache occupancy in the right-hand column should be inter-
preted as follows:
free Free storage space
clean Data of virtual volumes which are no longer mounted but which have been
saved to tape, i.e. valid duplicates of these volumes are available on tape. The
“clean” area can be used at any time for data recording, without the need to
rewrite the data, if the “free” area is not sufficient.
used This area contains maps of currently mounted virtual volumes.
dirty Modified data of virtual volumes which are no longer mounted. Although this
data has been changed, the changes have not yet been written back to tape.
This area cannot be made free for other volumes until the data has been written
back to tape and therefore been made “clean”.
The proportions of the individual classes are displayed in the appropriate field of the bar,
if there is enough space.
If you click the left mouse button on a cache column, the size of the occupied area (used +
clean + dirty) and the corresponding unpacked data volume are displayed. Due to data
compression, the saved data volume can be greater than the capacity.
In the steady state, the proportion of “free” data in the cache is low. When unloading a
written volume (“dirty”), CentricStor attempts to “clean” its data as soon as possible by
rewriting and then retain it in the cache for as long as possible. CentricStor automatically
adapts the resources used for rewriting to the number and scope of write requests: the more
the cache is occupied with “dirty” data, the more drives are used for Save requests.
If you click the right mouse button on a cache column, a context menu appears which you
can use to output statistical data (“Show Statistics”). Information on this is provided in the
section “Data which can be called via objects of the Global Status” on page 297 . The /DB
column represents the ufs file system containing the CentricStor metadata.