HP StorageWorks Storage Mirroring scripting guide (T2558-96074, February 2008)

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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
QJournalFreeSpace
Min
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