IBM V7000 Introduction And Implementation Manual page 85

MDisks can be added to a storage pool at any time to increase the capacity of the storage
pool. MDisks can belong in only one storage pool and only MDisks in unmanaged mode can
be added to the storage pool. When an MDisk is added to the storage pool, the mode
changes from unmanaged to managed and vice versa when you remove it.
Each MDisk in the storage pool is divided into a number of extents. The size of the extent is
selected by the administrator at creation time of the storage pool and cannot be changed
later. The size of the extent ranges from 16 MB up to 8 GB.
The extent size has a direct impact on the maximum volume size and storage capacity of the
clustered system. A system can manage 4 million (4 x 1024 x 1024) extents. For example, a
system with a 16 MB extent size can manage up to 16 MB x 4 MB = 64 TB of storage.
The effect of extent size on the maximum volume size is shown inTable 2-7, and lists the
extent size and the corresponding maximum clustered system size.
Table 2-7 Maximum volume capacity by extent size
Extent size
16 MB
32 MB
64 MB
128 MB
256 MB
512 MB
1024 MB
2048 MB
4096 MB
8192 MB
The effect of extent size on the maximum clustered system capacity is shown inTable 2-8.
Table 2-8 Extent size and effect on clustered system capacity
Extent size
16 MB
32 MB
64 MB
128 MB
256 MB
512 MB
1024 MB
2048 MB
4096 MB
8192 MB
Maximum volume capacity for normal
volumes (GB)
2048 (2 TB)
4096 (4 TB)
8192 (8 TB)
16384 (16 TB)
32768 (32 TB)
65536 (64 TB)
131072 (128 TB)
262144 (256 TB)
528288 (512 TB)
1056576 (1,024 TB)
Maximum storage capacity of cluster
64 TB
128 TB
256 TB
512 TB
1 PB
2 PB
4 PB
8 PB
16 PB
32 PB
Chapter 2. Introduction to IBM Flex System V7000 Storage Node
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