IBM 201 manual PSM notes

Once the cache file usage exceeds the warning threshold (configured in the PSM Volumes panel for the drive; the default value is 80 percent), PSM generates a warning message to the system event log (viewable via the Windows 2000 Event Viewer in the IBM NAS Admin console), and to the alert log in the Microsoft Windows 2000 for Network Attached Storage user interface. The name of the source for the message will be psman5. Additionally, while the cache file usage is above the warning threshold, PSM prohibits any attempt to create a new persistent image, and logs an error message (to the system log and alert log). The text of the error message that is logged in the system event log (from psman5) is “A persistent image could not be created due to error 0xe000102b”.

Note: The share settings are maintained in a persistent image. Therefore, granting access to all end-users only permits those users to access files and directories within the persistent image that they would have been able to access originally on the actual drive.

PSM notes

1.As mentioned, you can take and keep a maximum of 250 persistent images. These can be taken on local drives, or drives on the external storage that are logically local.

Note that on various panels, such as the New Persistent Image Schedule panel, you will see a field, Keep the last: (number of persistent images). The total number of persistent images that you enter in these fields will not override the maximum number of persistent images that you set in the Global Settings panel. For example, if your maximum number of persistent images is 10, and you enter in numbers in other fields that add up to greater than 10, only 10 persistent images will be taken.

2.You cannot take a persistent image of the maintenance drive (D:). Hence, you will not see it as a choice in either the New Persistent Image Schedule panel or the Create Persistent Image panel.

3.PSM stores the cache file for each drive on the drive itself. The first persistent image created on a particular drive will take a significant amount of time because the PSM cache file must be created (pre-allocated) for that drive.

The time required for creation depends on the configured size of the cache file (15 percent of the total drive size by default). Creation takes roughly three to four minutes per gigabyte. For example, a 10 GB cache file would take 30 to 40 minutes to create. You should create a persistent image for a drive before scheduling any persistent images for that drive, to build the cache file. You may then delete the persistent image that you just created if you do not need to keep it.

After the creation of the first persistent image on a volume, future persistent images on that volume will complete faster.

4.As mentioned, the default size of the cache file per drive is 15 percent of the total drive capacity. In most cases, that should be sufficient.

However, it is possible that it will not be enough to maintain the number of persistent images you wish to keep concurrently on the drive, given the amount of file-write activity to the drive. PSM will automatically take action to prevent the cache file from overflowing, because if that occurred, PSM would be forced to automatically delete all persistent images on the drive (once it cannot keep track of changes made to the drive, it cannot maintain a valid persistent image).

PSM takes the following actions as the cache file usage approaches a full condition:

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Chapter 6. Additional administrative functions 43