HP StorageWorks XP24000 Continuous Access Journal Software User and Reference Guide, v01 (T5278-96001, June 2007)

For further information on Per formance Monitor, see the H P StorageWorks XP24000 Performance
Monitor User's Guide.
To perform Continuous Access Journal (o r other) Remote Web Console o perations while Performance
Monitor is collecting data for one or more storage systems on the same storage system internal LAN:
1. If Performance Monitor is collecting a large amount of LDEV data, consider disabling
Performance M onitor LDEV data collection for one or more storage systems before using the
Remote Web Console software. Please see the HP StorageWorks XP24000 Performance Monitor
User's
Guide for instructions on disabling LDEV data collection.
2. If Performance Monitor is collecting data for more than three storage systems on the storage
system internal LA N, consider disconnecting Performance M onitor from one or more storage
systemsbefore using theRemoteWeb Consolesoftware. Please seethe HP StorageWorks
XP24000 Performance M onitor User's Guide for instructions on disconnecting Per formance
Monitor.
3. After you have disabled LDEV data colle ction and/or disconnected Performance M onitor, you
can
connect to the storage system using the Remote Web Console software, launch Continuous
Access Journal, and perform Continuous Access operations (for example, create pairs and
view pair status).
4. When you are finished performing Continuous Access Journal operations, exit Continuous
Access Journal, and disconnect the Remote Web Console software from the storage system.
5. After you have disconnected the Remote Web Console comp uter from the storage system, you
can
re-enable Performance Monitor data collection.
Planning of Journal Volumes
Data transfer speed for journal groups is affected by the specifications of journal volumes that the journal
groups use. Therefore, you n eed to think about specifications of journal volumes to be used by journal
volumes, in order to a chieve the data transfer speed that you want.
This s
ection explains what you need to c onsider when deciding on journal volume specifications.
The fo
llowing factors affect the speed for writing to and reading from journal volumes, particularly when
atem
porary communications path failure occurs between the primary storage system and the secondary
stor
age
system or when the amount of data transferred from hosts to the primary storage system is
increasing:
• RAID configuration of the RAID groups that will conta in the journal volumes
• Typ
es of physical volumes in the RAID groups that will contain the journal volumes
• Frequency of access to non-journal volumes in the RA ID groups that will contain the journal
volumes
• Dat
a
transfer speed required for the non-journal volumes mentioned above
• Disk usageratefor theRAIDgroups
The following factor affects the time during which data transfer with hosts can continue without being
influenced by a temporary c om munications pa th failure bet ween the primary storage system and the
secondar y storage system or without being influenc ed by an increase in the data to be transferred from
the
hosts to the primary storage system.
• C
apacity of the journal volumes
Data Transfer Speed Required for Journal Volumes
Figure 32 on page 71 illustrates how the data transfer speed (that is, the amount of data to be transferred
per unit of time) will change as time elapses, citing different t ypes of data transfer speed with Continuous
Access Journal. Data transfer speed bet ween hosts and the primar y storage system goes through two
phases: in one phase, the d ata transfer speed remains almost unchanged; in the other p hase, the data
transfer speed increases temporarily.
70
Preparing for Continuous Access Journal Operations