MSA 2040 SMU Reference Guide

28 Getting started
About size representations
Parameters such as names of users and volumes have a maximum length in bytes. ASCII characters are 1 byte; most
Latin (Western European) characters with diacritics are 2 bytes; most Asian characters are 3 bytes.
Operating systems usually show volume size in base 2. Disk drives usually show size in base 10. Memory (RAM and
ROM) size is always shown in base 2. In the SMU, the base for entry and display of storage-space sizes can be set
per user or per session. When entering storage-space sizes only, either base-2 or base-10 units can be specified.
10
(1+0)
4 Stripes data across
multiple RAID-1
sub-vdisks
Highest performance and data
protection (protects against
multiple disk failures)
High redundancy cost overhead:
because all data is duplicated,
twice the storage capacity is
required; requires minimum of four
disks
50
(5+0)
6 Stripes data across
multiple RAID-5
sub-vdisks
Better random read and write
performance and data protection
than RAID 5; supports more disks
than RAID 5; protects against
multiple disk failures
Lower storage capacity than RAID
5
Table 5 Vdisk expansion by RAID level
RAID level Expansion capability Maximum disks
NRAID Cannot expand. 1
0, 3, 5, 6 You can add 1–4 disks at a time. 16
1 Cannot expand. 2
10 You can add 2 or 4 disks at a time. 16
50 You can add one sub-vdisk at a time. The added sub-vdisk must contain the same
number of disks as each of the existing sub-vdisks.
32
Table 6 Size representations in base 2 and base 10
Base 2 Base 10
Unit Size in bytes Unit Size in bytes
KiB (kibibyte) 1,024 KB (kilobyte) 1,000
MiB (mebibyte)
1,024
2
MB (megabyte)
1,0 0 0
2
GiB (gibibyte)
1,024
3
GB (gigabyte)
1,0 0 0
3
TiB (tebibyte)
1,024
4
TB (terabyte)
1,0 0 0
4
PiB (pebibyte)
1,024
5
PB (petabyte)
1,0 0 0
5
EiB (exbibyte)
1,024
6
EB (exabyte)
1,0 0 0
6
Table 4 RAID level comparison (continued)
RAID
level
Min.
disks
Description Strengths Weaknesses