EMC CX500I Configuration Guide - Page 112

LUN size, Disk IDs, RAID type, RAID 1/0 or RAID 1 Group: disk-size

Page 112 highlights

Planning File Systems and LUNs Size (RAID Group size). Enter the user-available capacity in gigabytes (Gbytes) of the whole RAID Group. You can determine the capacity as follows: RAID 5 or RAID 3 Group: disk-size ∗ (number-of-disks - 1) RAID 1/0 or RAID 1 Group: (disk-size ∗ number-of-disks) / 2 RAID 0 Group: disk-size ∗ number-of-disks Individual unit: disk-size For example, • A five-disk RAID 5 or RAID 3 Group of 73-Gbyte disks holds 292 Gbytes; • An eight-disk RAID 1/0 Group of 73-Gbyte disks also holds 292 Gbytes; • A RAID 1 mirrored pair of 73-Gbyte disks holds 73 Gbytes; and • An individual disk of an 73-Gbyte disk also holds 73 Gbytes. LUN size. Enter the user-available capacity in gigabytes (Gbytes) of the LUN. You can make this the same size as the RAID Group, described previously. Or, for a RAID 5, RAID 1, RAID 1/0, or RAID 0 Group, you can make the LUN smaller than the RAID Group. You might do this if you wanted a RAID 5 Group with a large capacity and wanted to place many smaller capacity LUNs on it; for example, to specify a LUN for each user. However, having multiple LUNs per RAID Group may adversely impact performance. If you want multiple LUNs per RAID Group, then use a RAID Group/LUN series of entries for each LUN. Disk IDs. Enter the IDs of all disks that will make up the LUN or hot spare. These are the same disk IDs you specified on the previous worksheet. For example, for a RAID 5 Group in DAE2 on loop 0 (disks 10 through 14), enter 0010, 0011, 0012, 0013, and 0014. RAID type. Copy the RAID type from the previous worksheet. For example, RAID 5 or hot spare. For a hot spare (not strictly speaking a LUN at all), skip the rest of this LUN entry and continue to the next LUN entry (if any). If this is a RAID 3 Group, specify the amount of SP memory for that group. To work efficiently, each RAID 3 Group needs at least 6 Mbytes of memory. 5-18 EMC CLARiiON CX300, CX500, CX500i, and CX700 Storage Systems Configuration Planning Guide

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5-18
EMC CLARiiON CX300, CX500, CX500i, and CX700 Storage Systems Configuration Planning Guide
Planning File Systems and LUNs
Size
(RAID Group size). Enter the user-available capacity in
gigabytes (Gbytes) of the whole RAID Group. You can determine
the capacity as follows:
For example,
A five-disk RAID 5 or RAID 3 Group of 73-Gbyte disks holds
292 Gbytes;
An eight-disk RAID 1/0 Group of 73-Gbyte disks also holds
292 Gbytes;
A RAID 1 mirrored pair of 73-Gbyte disks holds 73 Gbytes;
and
An individual disk of an 73-Gbyte disk also holds 73 Gbytes.
LUN size
.
Enter the user-available capacity in gigabytes (Gbytes)
of the LUN. You can make this the same size as the RAID Group,
described previously. Or, for a RAID 5, RAID 1, RAID 1/0, or
RAID 0 Group, you can make the LUN smaller than the RAID
Group. You might do this if you wanted a RAID 5 Group with a
large capacity and wanted to place many smaller capacity LUNs
on it; for example, to specify a LUN for each user. However,
having multiple LUNs per RAID Group may adversely impact
performance. If you want multiple LUNs per RAID Group, then
use a RAID Group/LUN series of entries for each LUN.
Disk IDs
. Enter the IDs of all disks that will make up the LUN or
hot spare. These are the same disk IDs you specified on the
previous worksheet. For example, for a RAID 5 Group in DAE2
on loop 0 (disks 10 through 14), enter
0010
,
0011
,
0012
,
0013
,
and
0014
.
RAID type
. Copy the RAID type from the previous worksheet.
For example, RAID 5 or hot spare. For a hot spare (not strictly
speaking a LUN at all), skip the rest of this LUN entry and
continue to the next LUN entry (if any).
If this is a RAID 3 Group, specify the amount of SP memory for
that group. To work efficiently, each RAID 3 Group needs at least
6 Mbytes of memory.
RAID 5 or RAID 3 Group:
disk-size
(number-of-disks - 1)
RAID 1/0 or RAID 1 Group: (disk-size
number-of-disks) / 2
RAID 0 Group:
disk-size
number-of-disks
Individual unit:
disk-size