Chapter 7. Working With Storage Pools And Volumes; Understanding Storage Pools; Understanding Volumes - IBM BladeCenter S SAS RAID Controller Module Installation And User Manual

Chapter 7. Working with storage pools and volumes

You can divide your available storage into storage pools and volumes to customize
your configuration.

Understanding storage pools

A storage pool is a collection of disk drives that become a logical entity. When you
create a storage pool, you assign a RAID level to it which will provide a
redundancy level.
You can create a storage pool using IBM Storage Configuration Manager or by
using the create pool command in the RAID Controller command line interface
(see "create pool" on page 80).
Notes
v You should determine the size of your storage pool by the amount of space
v All disk drives in a storage pool must be the same type.
v A disk drive can only belong to one storage pool.
v If you use global spares to protect storage pools, ensure that any spare matches

Understanding volumes

After you create storage pools, you need to break the storage pools into discrete
areas of storage, which are called volumes. Volumes are the basic unit of storage
that are exposed to the Blade server and are created from the available space in a
storage pool. A volume is completely contained within a single storage pool,
however a storage pool can contain multiple volumes. After you create volumes,
you must map them to each individual Blade server. Each Blade server can access
one or more of these volumes.
Volumes are typically defined as either data volumes, which are used to store
application date, or boot volumes, which are used to store the operating system
image. For each volume, you need to determine the following characteristics:
v The size (in GBs)
v The blade server or servers that will have access to the volume
v Any applications on the blade servers that need access to the volume
You define volumes using IBM Storage Configuration Manager or by using the
create volume command in the RAID Controller command line interface (see
"create volume" on page 81).
Notes:
v The minimum size of a volume is 1 MB. The maximum size of a volume is the
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:
required by your application. Once you have determined whatever constraints
are put in place by the application, then you can weigh the performance
enhancement versus cost to determine the RAID level to use.
the capacity, speed and type of the drives in the storage pool for which it is
used.
maximum size of the storage pool in which the volume resides.
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