HighPoint Rocket 700 Series User Manual page 24

Foreground: The array initialization process will be set at high priority. During this time array is not
•
accessible, but the initialization process will complete much faster.
• Background: The array initialization process will have a lower priority. During this time the array
will be accessible, but the initialization process will take much longer to complete.
Note: Initializing takes a significant amount of time (approximately 2 hours per 1 TB when using hard drives).
Foreground initializing the array will completely zero out the data on the disks, meaning the disk will be completely
wiped and every bit on the disk will be set to 0. Background initialization means the array will still be created, and
you can still write new data onto the array. But when your array requires rebuilding, residual data left behind may
interfere with the process.
Cache Policy (Default: Write Back)
Write Back – Any data written to the array will be stored as cache, resulting in better I/O performance at the risk of
data failures due to power outages. Data will be stored as cache before it is physically written to the disk; when a
power outage occurs, any data in the cache will be lost.
Write Through – Data written to an array is directly written onto the disk, meaning lower write performance for
higher data availability. Without cache acting as a buffer, write performance will be noticeably slower but data loss
due to power outages or other failures is significantly minimized.
Block Size (default: 64K)
[64K to 128K are the supported block sizes]
Adjusting the block size towards your disk usage can result in some performance gain.
In a typical RAID configuration, data of the virtual drive is striped (or spread across) the physical drives. Having a
smaller array block size will increase the likelihood of accessing all physical drives when processing large I/O requests.
Multiple physical drives working in parallel increases the throughput, meaning better performance.
For smaller I/O requests (512 bytes to 4 kilobytes), it is better to have each individual disks handle their own I/O
request, improving the IOPS (I/O per second), rather than having one tiny I/O request being handled by multiple
disks.
Capacity (Default: Maximum)
The total amount of space you want the RAID array to take up. When creating RAID levels, disk capacities are limited
by the smallest disk.
An example of how disk capacities are limited by smallest disk.
You have 2 drives connected to the enclosure.
•
• The first drive is 6 TB, the second is 4 TB
• After creating a RAID level 1 using both drives and maximum capacity, the first drive will have 2 TB, the
second 0 TB of free capacity
• The free capacity on the second drive can be used to create a separate array with other drives.
You may also choose how much space each array will utilize. You can use the remaining space to create another array
(up to 4 arrays are supported).
(Recommended)
24