HP StorageWorks Storage Mirroring for Linux User's Guide (T2558-96317, June 2009)

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application. In this case, you would need to configure the applications so that they collectively do
not exceed the amount of RAM on the server. Perhaps on a server with 1 GB of RAM running the
application and Storage Mirroring, you might configure the application to use 512 MB and
Storage Mirroring to use 256 MB, leaving 256 MB for the operating system and other applications
on the system. Many server applications default to using all available system memory, so it is
important to check and configure applications appropriately, particularly on high-capacity
servers.
Any changes to the memory usage will not take effect until the Storage Mirroring daemon has
been restarted on the server.
 Maximum disk space for queue—This is the maximum amount of disk space, in MB, in the
specified Folder that can be used for Storage Mirroring disk queuing, or you can select Unlimited
which will allow the queue usage to automatically expand whenever the available disk space
expands. When the disk space limit is reached, Storage Mirroring will automatically begin the
auto-disconnect process. By default, Storage Mirroring will use an unlimited amount of disk space.
Setting this value to zero (
0) disables disk queuing.
 Minimum Free Space—This is the minimum amount of disk space in the specified Folder that
must be available at all times. By default, 50 MB of disk space will always remain free. The
Minimum Free Space should be less than the amount of physical disk space minus Maximum
disk space for queue.
 Alert at following queue usage percentage—This is the percentage of the disk queue that
must be in use to trigger an alert message in the Linux system log. By default, the alert will be
generated when the queue reaches 50%.
NOTE: The Maximum disk space for queue and Minimum Free Space settings work in
conjunction with each other. For example, assume your queues are stored on a 10 GB
disk with the Maximum disk space for queue set to 10 GB and the Minimum Free
Space set to 500 MB. If another program uses 5 GB, Storage Mirroring will only be
able to use 4.5 GB so that 500 MB remains free.