Choosing The Data Block Size; Creating And Managing Arrays; Stock Number: 510685-00, Rev. A Page; Formatting The Array - Adaptec AHA-3980 User Manual

Creating and Managing Arrays

Check with your vendor or your drive documentation to learn how
your drives handle low-level formatting. If you find the low-level
formatting speed is acceptable to you, low-level formatting is the
better choice.

Choosing the Data Block Size

When formatting arrays other than RAID 1 arrays, you must choose
the size of the data blocks that will be striped across the array. The
allowable sizes are 8, 16, 32, or 64 KBytes; the default size is
16 KBytes. For best performance, the data block size should be the
same size you intend to use for the volume block size, or one size
larger. (For information on volume block sizes, see the NetWare
documentation.)
Note:
You do not choose a data block size for RAID 1 arrays
(mirrored arrays with only two disks), because they do not
involve striping across disks.

Formatting the Array

Once you decide on the formatting method and the block size, fol-
low these steps to initialize or low-level format an array:
1
If the system has only one array, skip to step 2. Otherwise,
from the System menu select the array you want to format. The
Main menu for that array appears.
2
From the Main menu, select Format Array. The Format menu
appears.
3
Select the RAID format: RAID0, RAID5, Mirrored, RAID0 CVT,
or RAID5 CVT. (For a description of these RAID levels, see
Array Types on page 1-1.) The Select Format Mode menu appears.
Note:
If you selected a different RAID level when you
defined the array, the format you select here super-
sedes that selection. This causes no problems with the
array, as long as the number of drives you defined is
suitable for the RAID format you select here. If the
number is unsuitable, an onscreen message tells you.
4-2

Creating and Managing Arrays

Stock Number: 510685-00, Rev. A
Print Spec Number: 493069-00
Current Date: 3/3/99
Page: 4-2
ECN Date: 3/28/95