EMC Symmetrix DMX-3

Storage capacities and global memory requirements
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Introducing the Symmetrix DMX-3
Storage capacities and global memory requirements
This section describes the Symmetrix DMX-3 storage capacities and
global memory requirements.
Storage capacities
The Symmetrix DMX-3 offers 73 GB, 146 GB, 300 GB, 450 GB, and
500 GB disk drives and can be configured with from 96 to 1,920 disk
drives.
The capacities are based on storage capacity of each disk drive type
and the following storage protection options:
◆ Mirrored (RAID 1)
◆ RAID 10, RAID 1/0
◆ SRDF
◆ RAID 5 (3+1) or RAID 5 (7+1)
◆ RAID 6 (6+2) or RAID 6 (14+2)
Note: Appendix A, “Symmetrix DMX-3 Specifications,” contains additional
information on drive and system capacities.
Factors affecting
storage capacity
The following factors affect disk storage capacity:
◆ Drive capacity size
◆ Type of data protection options used
◆ Internal Symmetrix File System (SFS) usage — A Symmetrix
DMX-3 reserves two SFS logical volumes consisting of 6,140
cylinders each (slightly less than 6 GB). These volumes are
protected using mirroring, consuming slightly less than 24 GB
total physical space.
◆ The size of the blocks — 512 or 520 bytes per block
◆ Vault devices — Symmetrix DMX-3 uses vault devices for
vaulting data from global memory during a power-down
operation. Vault devices require 5 GB of space. For each pair of
disk directors in a DMX-3, 160 GB of total capacity is reserved for
vaulting data from memory during system powerdown.
Note: “Configuration rules for vault devices” on page 68 and “Vaulting”
on page 170, contain more information on vaulting.