Changes to the characteristics of your virtual media through iSeries Navigator are performed by selecting Configuration and Service→ Hardware → Ταπε
∆εϖιχεσ → Tape Image Catalogs, Right-click your image catalog select List Volumes, then right-click on your volume and select Properties as shown in Figure 3-44 on page 94, Figure 3-45 on page 94, and Figure 3-46 on page 95.
Figure 3-44 List image catalog volumes via Navigator
Figure 3-45 Volume properties selected via Navigator
Figure 3-46 Volume Properties via Navigator
If viewing from a 5250 emulation session, the volume characteristics can be viewed by the Work with Image Catalog Entries (WRKIMGCLGE) command and after pressing enter, pressing F11 (up to three times) shows the volume
characteristics. The first screen of the volume characteristics in the Work with Image Catalog Entries screen is shown in Figure 3-47 on page 96.
Figure 3-47 Volume characteristics via 5250 emulation
From the Volume Properties in iSeries Navigator or the Work with Image Catalog Entries screen on a 5250 emulation session, you have the ability to change:
Volume Index (NEWCLGIDX)
Specifies a new index number to be used for the image catalog entry. If an entry currently exists at the specified index location, the new entry will be inserted and all entries at or below the specified index number will be incremented by 1. This determines which order your volumes are located in the image catalog.
– Current (*SAME) - The index number will not be changed.
– 1-256 - Specifies the image catalog index number to be used.
Write protect (WRTPTC)
Specify whether this catalog entry should be write protected or not. By write protecting this catalog entry, no write operations will be allowed to it. This
Work with Image Catalog Entries
parameter cannot be changed while the volume is in a MOUNTED status.
This parameter is not allowed for reference or dependent image catalogs.
– Current (*SAME) - The value for write protect will not be changed.
– Yes (*YES) - Specifies that this catalog entry is to be write protected. This will prevent write operation from being done to it.
– No (*NO) - Specifies that this catalog entry is not to be write protected.
This will allow write operations to be done to this catalog entry.
Volume size (IMGSIZ) -Specifies the maximum size allowed for this tape image file.
If the specified image size is larger then the current file size then the new maximum size is set and the file size is increased. If the specified size is smaller than current maximum image size and the data stored in the image file is less than the specified value then the file will be reduced to the specified size otherwise the command will fail. This parameter is only allowed for tape type image catalogs. This parameter is not allowed for reference or
dependent image catalogs.
– Minimum size (*MIN) - The allocated image file size is truncated or shrank to the size of the data stored in the file.
– 48-1000000 - Specify the maximum number of megabytes allowed for this tape image file.
Allocate Storage size (ALCSTG) - Specifies for tape image files, whether to allocate the entire amount of storage specified on the Image size (IMGSIZ) parameter.
This parameter is only allowed for tape type image catalogs. This value cannot be changed while the volume is in a MOUNTED status. This parameter is not allowed for reference or dependent image catalogs.
– Minimum size (*MIN) - Specifies to change the storage allocation to match the storage required to contain the existing image file data. If performing a save, the image file size is increased dynamically. However, the image file size will no longer increase once the system reaches 5% or 5G storage remaining, whichever value is the lesser. This value is not valid for reference or dependent catalogs (catalog shadowing).
– Image size (*IMGSIZ) - Specify to change the storage allocation to be the entire amount of storage for this image file. This is the value that was specified on the Image size (IMGSIZ) parameter of the ADDIMGCLGE command.
Better understanding of Allocate Storage (ALCSTG)
In the previous example, after saving a library to our virtual volume, we saw that the volume took up 10.7% of the 1000MB (maximum size) allocated for that virtual volume. The 10.7% of the 1000MB allocated
means that 107MB of actual data (112MB including the image file and its information) is contained on the system. In our previous example, we did not change the ALCSTG, so it will dynamically allocate space as needed.
This means that it allocates 107MB of space plus any extra it may have allocated. In the example, the properties tab shows 160MB is allocated.
However, if the Allocate Storage (ALCSTG) was set to Image Size (*IMGSIZ), then since the maximum size is 1000MB, the system would still keep the other 893MB of space allocated so that it cannot be used by anything else other than saving to this specific virtual volume. If you do not wish to preallocate this full space or any extra space for this virtual volume, then the proper way to deallocate this extra space (but still allow for the volume to write up to a total of 1000MB) is to Change the allocation to the Minimum size - ALCSTG(*MIN).