Database Reference
In-Depth Information
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You need
parted
if you need to create Luns with a size > 2 TB. such devices cannot be addressed by the
Master Boot record (MBr) format, but rather need a guID partition (gpT) table. This is a limitation of the addressing
scheme of the hard disk, not of the operating system.
Note
Once the LUN you are interested in is discovered on the operating system you can partition it. Most often you will
get worldwide IDs from the storage team to use on the new database server. Using the
/dev/disk/by-id
directory it is
possible to identify the SAN storage based on these WWIDs and to partition it. Pass the complete path of the disk as an
argument to
fdisk
, as shown in this example:
# fdisk /dev/disk/by-id/scsi-1IET_00010001
Following this, you need to create a partition spanning the whole disk. The steps are shown in the below listing,
where the following operations are carried out:
•
The LUN is selected
•
The display unit it changed to sectors
•
A new primary partition is created with an offset. Different vendors require different offsets-check
with your storage administrator on how to define the partition to match the requirements stated
in the documentation. Also, many advanced formatting devices such as flash based storage are
using a 4096 byte sector size instead of the previous 512 byte sectors. For optimal performance,
partitions have to be aligned at 4k boundaries on these types of devices.
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as you will have noticed the examples presume an isCsI Lun. storage provided via Fibre Channel uses a
different notation for the WWID, but other than that the steps are identical.
Note
Following is an example. The text in bold are the responses that I typed in while generating the example.
# fdisk /dev/disk/by-id/scsi-1IET_00010001
WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
switch off the mode (command 'c') and change display units to
sectors (command 'u').
Command (m for help):
u
Changing display/entry units to sectors
Command (m for help):
c
DOS Compatibility flag is not set
Command (m for help):
n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4):
1
First sector (2048-4196351, default 2048):
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