Hp StorageWorks XP Remote Web Console Software Instrukcja Użytkownika Pobierz pdf (Strona 67)

Planning of Journal Volumes

Why Planning is Necessary

Data transfer speed for journal groups is affected by speciﬁcations of journal volumes that the journal

groups use. Therefore, you need to think about speciﬁcations of journal volumes to be used by journal

volumes, in order to achieve the data transfer speed that you want.

What to Consider for Planning

This section explains what you need to consider when deciding on journal volume speciﬁcations.

The following factors affect the speed for writing to and reading from journal volumes, particularly

when a temporary communication path failure occurs between the primary storage system and the

secondary storage system, or when the amount of data transferred from hosts to the primary storage

system is in

creasing:

• RAID conﬁguration of the RAID groups that will contain journal volumes

• Types of physical volumes in the RAID groups that will contain journal volumes

• Frequency

of access to non-journal volumes in the RAID groups that will contain journal volumes

• Data transfer speed required for the non-journal volumes mentioned above

• Disk usageratefor RAID groups

The following factor affects the time during which data transfer with hosts can continue without being

inﬂuenced by a temporary communication path failure between the primary storage system and the

secondary storage system, or without being inﬂuenced by an increase in the data to be transferred from

hosts to t

he primary storage system.

• Capacity of journal volumes

HowtodoPlanning

Data Transfer Speeds for Journal Volumes

Figure 13 on page 68 illustrates how the data transfer speed (i.e., the amount of data to be transferred

per unit of time) will change as time elapses, citing different types of data transfer speed with URz.

Data transfer speed between hosts and the primary storage system goes through two phases; in one

phase the data transfer speed remains almost unchanged, and in another phase the data transfer

speed

increases temporarily.

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Hp StorageWorks XP Remote Web Console Software Instrukcja Użytkownika Strona 67