HP StorageWorks Storage Mirroring Scripting Guide (T2558-96327, April 2009)

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PriorityClass The priority level at which the Storage Mirroring service runs.
Values:
3
Default:
3
GUI Setting: None
The Storage Mirroring service runs at normal priority by default, which is
adequate in most cases. However, there are some high-load situations where
Storage Mirroring needs a higher priority in order to move data through its
queues and transmit the data to the target. One specific example is with bulk
inserts to a SQL Server
®
database. During this operation, SQL Server uses so
much CPU that Storage Mirroring does not get enough CPU cycles to transmit
data as quickly as it otherwise might. Boosting the priority of the Storage
Mirroring service process to high on the source enables Storage Mirroring to
transmit data as quickly as possible and results in less data being queued on
the source. This boost usually results in better overall performance because
Storage Mirroring will not queue as much data to disk, which degrades overall
performance. If Storage Mirroring replication traffic is not being sent to the
target as quickly as possible during high load processes, boost the priority of
Storage Mirroring on the source. This condition can be recognized by
monitoring queued replication, and network and CPU utilization. If CPU
utilization is high, a lot of data is being queued, and the utilization of the
network between the source and target is low, that means Storage Mirroring
is not getting enough CPU to transmit data as quickly as possible.
ProductCode Used by the Storage Mirroring installation program to maintain the
installation settings for an upgrade. Do not modify this entry.
ProductName Used by the Storage Mirroring installation program to maintain the
installation settings for an upgrade. Do not modify this entry.
QJournalDir The location where the queue is stored.
Values: any valid path
Default: the location specified during the installation
GUI Setting: Server Properties, Queue tab, Location, Folder
For best results and reliability, you should select a dedicated, non-boot
volume. The queue should be stored on a fixed, local NTFS volume.
This location also stores the Storage Mirroring driver pagefile.
QJournalFileSize The size, in MB, of each queuing transaction log file.
Values: any valid file size, up to 4095 MB
Default: 5
GUI Setting: None
QJournalFree
SpaceMin
The minimum amount of disk space, in MB, in the specified
QJournalDir
that must be available at all times.
Values: dependent on the amount of physical disk space available
Default: 50
GUI Setting: Server Properties, Queue tab, Memory and Disk Usage,
Minimum Free Space
The QJournalFreeSpaceMin should be less than the amount of physical disk
space minus
QJournalSpaceMax.
QJournalPreload The number of operations being pulled from the disk queue at one time. Do
not modify this setting.
Server Setting Description