Provisioning Volumes; Full Provisioning; Thin Provisioning; Best Practice For Setting Volume Size - HP StorageWorks P4000 User Manual

Provisioning volumes

Configure volume size based on your data needs, how you plan to provision your volumes, and
whether you plan to use snapshots. The SAN/iQ software offers both full and thin provisioning for
volumes.
Table 39 Volume provisioning methods
Method

Full provisioning

Thin provisioning

Full provisioning
Full provisioning reserves the same amount of space on the SAN as is presented to application servers.
Full provisioning ensures that the application server will not fail a write. When a fully provisioned
volume approaches capacity, you receive a warning that the disk is nearly full.
Thin provisioning
Thin provisioning reserves less space on the SAN than is presented to application servers. The SAN/iQ
software allocates space as needed when data is written to the volume. Thin provisioning also allows
storage clusters to provision more storage to application servers than physically exits in the cluster.
When a cluster is over-provisioned, thin provisioning carries the risk that an application server will
fail a write if the storage cluster has run out of disk space. The SAN/iQ software adds utilization and
over-provisioned events as the cluster approaches 100% utilization. You can add capacity to the
cluster or delete unneeded snapshots to accommodate additional volume growth.
NOTE:
Paying attention to the space utilization events on over-provisioned storage clusters is critical to prevent
a write failure on a thin volume.

Best practice for setting volume size

Create the volume with the size that you currently need. Later, if you need to make the volume bigger,
increase the volume size in the CMC and then expand the disk on the server. In Microsoft Windows,
you expand a basic disk using Windows Logical Disk Manager and Diskpart. For detailed instructions,
see "Changing the volume size on the

Planning data protection

Data protection results from creating data redundancy for volumes on the SAN. Configure data
protection levels, called Network RAID, when you create a volume. You can store two, three, or four
mirrored copies of your data using Network RAID-10, Network RAID-10+1, or Network RAID-10+2.
Network RAID-5 and Network RAID-6 store parity on multiple storage systems in the cluster. Under
some workloads that write the data infrequently, Network RAID-5 and Network RAID-6 provide better
190 Provisioning storage
Settings
Volume size x Network RAID level factor = amount of space allocated
on the SAN
Volume size x Network RAID level factor >= amount of space allocated
on the SAN
server" on page 203.