ATTO Technology Diamond Storage Array S-Class - Manual (Page 27)

16
Numbering conventions
Examples
JBOD mode uses 24 LUNs. Each LUN is
equivalent to one physical drive. The array will
operate with several sleds missing, but the empty
sled(s) will be treated as offline and will not be
configurable.
RAID Level 0 ( QuickRAID0 [n] ) With a fully
populated array, RAID 0 may be configured as 1,
2, 3, 4, 6, or 12 LUNs. As
QuickRAID0 1 , all 24
physical drives are configured as a single stripe
group or LUN. You may also configure two LUNs
of 12 drives each, three LUNs of eight drives
each, four LUNs of six drives each, six LUNs of
four drives each and 12 LUNS of two drives each.
(See Exhibit 6.2-3 in
RAID Level 0 on page 53). The
command assumes there are 24 drives available to
configure the specified number of LUNS.
RAID Level 1 ( QuickRAID1 ) has no options: the
array will be configured into six groups, LUNs 1-
6, with each LUN containing two physical sleds;
each sled in the LUN will be a mirror image of the
other sled in the LUN.
RAID Level 10 ( QuickRAID10 ) The QuickRAID10
command first creates six mirrored groups, then
stripes them into groups of one, two or three
RAID 10 groups. Each group is a LUN. Issuing
QuickRAID10 2 , the 12 physical sleds are
configured as six mirrored pairs, then striped into
two LUNs.
RAID Level 5 ( QuickRAID5 ) with a fully
populated Array may be configured as 1, 2, 3 or 4
LUNs. As
QuickRAID5 1 , all 24 physical drives are
configured as a single RAID 5 LUN. You may
also configure two LUNs of 12 drives each, three
LUNs of eight drives each, or four LUNs of six
drives each. RAID Level 5 parity will reduce the
usable capacity of each LUN by the equivalent of
one drive sled.
Unique serial number for each LUN
Each LUN in a system has a unique 24-character
serial number which is updated when a system
configuration changes. It is stored in a Device
Association Table on each drive.
When a drive or sled is replaced in QuickRAID
configurations that allow for hot swap, a new
serial number will be computed and will in turn be
stamped onto all member drives of the RAID
group. The CLI command
LUNInfo or the
ExpressNAV interface page Logical Units will
display the serial number for each drive.
Format of the 24 characters is defined in the chart
below:
Character
Placement Valid values
Example of unique serial number for a JBOD configuration: 1231231231231231231XAC0
0-19 Any ASCII
char
Drive Serial Number
20 1 for Raid1
A for Raid10
0 for Raid0
5 for Raid5
X for JBOD
RAID Configuration Character
21 A – Z LUN Configuration Iteration Character: starts at A and increments every time a member drive is
replaced in a RAID Group. Reverts back to A any time the Generation Character is updated
22 A – Z Generation Character: starts at A and increments every time a new configuration is stamped on the
system. When it reaches Z, rolls over to A.
23 0 Reserved for future use