HP-UX Reference (11i v1 05/09) - 4 File Formats (vol 8)

a
arraytab(4) arraytab(4)
sequence label dN, where N is a number from 0 to 4. Subsequent lists may be used to create
drive groups larger than 5 disks. The disk identifier label is a string formed from the vendor
ID and product ID strings returned from a SCSI Inquiry message, separated by ‘‘
_’’. Certain
constraints are made for the drive groups and drive lists, depending upon the number of drives
and the RAID level chosen. See restrictions below.
lp num Logical partition within the logical configuration. A logical configuration will have one or more
logical partitions, with each logical partition consisting of a portion or the whole of a drive
group (See LUN type). Address space is allocated to each logical partition in the order in
which it is found in the table, and begin start from the beginning block of the disk group. A
logical partition number corresponds with the SCSI logical unit (LUN) number.
lt str Logical partition or LUN type. A logical partition may be either ‘‘regular LUN’’ (
reg) or ‘‘sub-
LUN’’ (
sub). A sub-LUN allows configuring multiple logical disks for a group of disks, each to
an arbitrary capacity. A regular LUN allows a logical disk capacity of the composite disk capa-
city of a group of drives, or 2 GByte, whichever is smaller. When the regular LUN option is
used, the capacity parameter is ignored by the array controller. Additional logical drives may
be configured to use the remaining capacity beyond 2 GByte if the regular LUN mode is
chosen.
bs num Block size of the logical partition or LUN in bytes. This value must be specified in increments
of the native disk mechanism sector size. Currently supported values are 512, 1024, 2048,
4096 bytes.
cv num Capacity of the logical partition or LUN in blocks. If this value is set to 0, the array will
configure as many blocks as are available (not previously configured in another LUN).
ss num Segment size. The size in bytes of a contiguous segment of the logical address space which will
reside on a single physical disk. This allows controlling how many disks are involved with a
single I/O request. If I/O requests are mostly random, single block requests, this value should
be set to the block size. If the I/O requests are typically more than a single sequential block,
then this value should be set to the number of bytes which minimizes the number of disks
necessary to service most I/Os. The value must be an integral number of the block size.
is num The size in bytes of the first segment of the LUN. This allows this area to be set to a size
different than the remainder of the disk, an area typically used as the boot block for some sys-
tems. This must be an integral number of the block size. If there are no special requirements,
this parameter should be set to 0.
rl str RAID level. Acceptable strings are { RAID_0, RAID_1, RAID_3, RAID_5}. The RAID
modes are described above.
gn str Group name. This is the label used to identify the physical drive group or configuration to be
used with the logical configuration.
gs num Number of physical drives in the drive group.
rs num Reconstruction size. This is the number of logical disk blocks which will be reconstructed in
one operation when a drive data set is being repaired. A larger value will cause the recon-
struction to complete more quickly (and efficiently), but will cause longer delays in processing
other I/O requests.
rf num Reconstruction frequency. This is the period of time between reconstruction operations,
specified in 0.1 Sec. (see Reconstruction Size). This parameter is useful in systems which do
not do I/O request queuing to allow I/Os to process smoothly while reconstructing the data set.
lf num LUN configuration flags. There are 16 possible LUN configuration flags. Currently only 6 of
these flags are defined. It is not recommended that these fields be altered. The flags are used
to enable certain features of the array controller for the specified LUN. The flags may be set
by specifying the hexadecimal value for all the flags. The flags are defined as follows:
Bit 0 off Not used.
Bit 1 on Automatic reconstruction disable. Enabled allows the array controller to
automatically begin data restruction when the replacement of a failed
disk is detected.
Bit 2 off Not used.
Section 4−−22 Hewlett-Packard Company − 3 − HP-UX 11i Version 1: September 2005