Raid Levels; Logical Drive Specifications By Supported - IBM System Storage DS3000 Programming Manual

Note: FlashCopy Logical Drive and Enhanced Remote Mirroring are premium features that you must
activate before you can use them. For more information about FlashCopy logical drives, see Chapter 5,
"Using the FlashCopy Premium Feature," on page 5-1. For more information about Enhanced Remote
Mirroring, see Chapter 8, "About Enhanced Remote Mirroring premium feature," on page 8-1.
The number and capacity of the logical drives in your storage subsystem depends on the type of
controller in the storage subsystem. The following table lists the maximum values for the logical drives in
a storage subsystem by specific controllers.
Table 4-4. Logical Drive Specifications by Supported Controller Model
Specifications DS3200,
DS3300,
DS3400
Maximum 256
logical drives per
storage
subsystem
Maximum 256
logical drivers
per partition
Maximum SeeTable 4-3 on page 4-10.
logical drive size
(less than 12 GB
for overhead)
Maximum disk See Table 4-3 on page 4-10.
drives per
subsystem using
RAID 5
Maximum N/A
remote mirrors
Note: Addressable capacities greater than 2 TB are possible with some operating systems. Currently these
operating systems are Windows, Solaris 9, Solaris 10, AIX 5.2, AIX 5.3, HP-UX 11.23, and Linux 2.6.
A Windows operating system and a Linux 2.6 operating system using 500 GB disk drives can have a
maximum logical drive size of 112 TB (224 x 500) when controller firmware version 7.10.xx.xx or later is
installed in the DS4000 storage subsystem, or when controller firmware version 7.30.xx.xx is installed in
the DS5000 storage subsystem.
1
Firmware 7.77.xx.xx and later supports 512 logical drives per storage subsystem. Firmware 7.70.xx.xx
supports only 25 logical drives per subsystem.
2
Firmware 7.77.xx.xx and later supports 256 logical drives per partition. 7.70.xx.xx supports only 32
logical drives per partition
3
Requires firmware 7.77.xx.xx and later and enabling of the 16 remote mirrors premium feature.

RAID Levels

The RAID level defines a storage architecture in which the storage capacity on the disk drives in an
subsystem is separated into two parts: part of the capacity stores the user data, and the remainder stores
redundant or parity information about the user data. The RAID level that you choose determines how
user data is written to and retrieved from the disk drives. Using the script commands, you can define
five RAID levels: RAID 0, RAID 1, RAID 3, RAID 5, and RAID 6. Each level provides different
performance and protection features.
DS3500 DCS3700 DCS3700 storage
series subsystem with
Performance Module
Controllers
512 512 2048
1
256 256 256
2
16 16 16
3
DS4200, DS4800
DS4700
1024 2048
256 256
64 128
Chapter 4. Configuring a Storage Subsystem
DS5100, DS3950,
DS5300 DS5020
2048 1024
256 256
128 64
4-13