Справочник Пользователя для IBM Flex System V7000 Expansion Enclosure 4939H29
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8068ch02-HW Intro.fm
Draft Document for Review January 29, 2013 12:52 pm
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IBM Flex System V7000 Storage Node Introduction and Implementation Guide
Figure 2-14 IBM Flex System V7000 Storage Node with single and multi-tier pools
2.5.9 Volumes
A volume is a virtual logical disk that is presented to a host system by the clustered system. In
our virtualized environment, the host system has a volume mapped to it by IBM Flex System
V7000 Storage Node. The IBM Flex System V7000 Storage Node translates this volume into
a number of extents, which are allocated across MDisks. The advantage with storage
virtualization is that the host is “decoupled” from the underlying storage, so the virtualization
appliance can move the extents around without impacting the host system.
our virtualized environment, the host system has a volume mapped to it by IBM Flex System
V7000 Storage Node. The IBM Flex System V7000 Storage Node translates this volume into
a number of extents, which are allocated across MDisks. The advantage with storage
virtualization is that the host is “decoupled” from the underlying storage, so the virtualization
appliance can move the extents around without impacting the host system.
The host system cannot directly access the underlying MDisks in the same manner as it could
access RAID arrays in a traditional storage environment.
access RAID arrays in a traditional storage environment.
There are three types of volumes:
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Striped Volume
A striped volume is allocated using one extent from each MDisk at a time in the storage
pool. This process continues until the space required for the volume has been satisfied. It
is also possible to supply a list of MDisks to use.
pool. This process continues until the space required for the volume has been satisfied. It
is also possible to supply a list of MDisks to use.
��
Sequential Volume
A sequential volume is where the extents are allocated one after the other from one Mdisk.
If there is not enough space on a single Mdisk the creation of the sequential volume fails.
If a volume is required to be expanded the sequential volume is converted to a striped
volume by policy when the expansion occurs
If there is not enough space on a single Mdisk the creation of the sequential volume fails.
If a volume is required to be expanded the sequential volume is converted to a striped
volume by policy when the expansion occurs
Figure 2-15 on page 65 shows examples of the striped and sequential volume types.