Storage System Operation When Ldevs Are Formatted; Quick Format Function - HP XP7 User Manual

Formatting function
Quick Format

Storage system operation when LDEVs are formatted

The storage system acts in one of two ways immediately after an LDEV is added, depending on
the default settings in the storage system.
The storage system automatically formats the added LDEV. This is the default action.
The storage system blocks the LDEV instead of automatically formatting it.
To confirm or change the default formatting settings on the storage system, contact the administrator.
Users who have the Storage Administrator (Provisioning) role can change these default formatting
settings.

Quick Format function

The Quick Format function formats internal volumes in the background. While Quick Format is
running in the background, you can configure your system before the formatting is completed.
Before using Quick Format to format internal volumes, ensure that the internal volumes are in
blocked status.
I/O operation from a host during Quick Format are allowed. Formatting in the background might
affect performance.
Because shared resources such as MP blades or cache paths are used during quick format
operations, all host I/Os in a storage system may be affected.
Particularly, in the following cases of quick format operations, due to the load concentration on a
specific component at the same time, the I/O performance of the host may decrease while
performing of the quick format.
In a configuration that satisfies both of these conditions, many quick formats started at the
same time.
◦
The number of modules is one or two.
◦
Configuration of CPEX (Cache Path control adapter and PCI EXpress path switch), DKA
(DisK Adapter), and CHA (CHannel Adapter) are minimum in each module
In a configuration that satisfies either one of these conditions, quick formats started.
◦
In the multiple modules configuration, the number of CPEXs, DKAs, and CHAs that are
installed in each module, are extremely unbalanced between modules.
For example, in the multiple modules configuration, one module contains many CPEX,
DKA, and CHA, and other modules contains CPEX, DKA, and CHA of the least number.
◦
In a module, numbers of CPEXs, DKAs, and CHAs that connect to CPEX (Basic) or CPEX
(Option) are extremely unbalanced between CPEX (Basic) and CPEX (Option).
For example, inside of one module, CPEX (Basic) is connected by many DKAs, CHAs, or
other devices. However, CPEX (Option) is connected by DKAs, CHAs, or other devices
of the least number.
For configurations such as those described above, perform the quick format operation on one LDEV
first to confirm that the I/O performance of the host does not decrease. After that, it is strongly
recommended that the number of quick format operations you perform at the same time is increased
one by one.
58 Configuring custom-sized provisioning
Corresponding volume
External volume
Internal volume