3Ware 9500S-4LP Installation Guide - Page 57

Initializing Units, RAID 0 Units, For RAID 5 and RAID 50 Units

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Initializing Units Initializing Units Performance of RAID 5 units with 5 or more disks, and RAID 50 units with 10 or 12 disks configured into two subunits will improve after the unit has been initialized. For these configurations, foreground initialization (also known as "zeroing") starts immediately. If you want to begin using the units right away, you can halt the zeroing process and initialize them in the background later, after the operating system is booted. (The initialization process can take several hours, depending on the size of your drives.) The disadvantage of initializing the units later in the background is that the performance RAID 5 and RAID 50 arrays will be lower until initialization is complete. Information about initialization for each of the different RAID types is described below. RAID 0 Units RAID 0 units do not need to be initialized and are immediately available for use with full performance when created. For RAID 5 and RAID 50 Units RAID 5 units with 3 or 4 disks do not need to be initialized and are fault tolerant upon creation. Similarly, RAID 50 units with 6, 8, or 9 disks, and RAID 50 with 12 disks configured into 3 subunits of 4 or 4 subunits of 3, do not need to be initialized. This is because these configurations use an optimized writing technique which does not have to be valid to provide fault tolerance. RAID 5 units with 5 or more disks, and RAID 50 units with 10 or 12 disks configured into two subunits do need to be initialized for full performance. For these configurations, initialization begins automatically after you create them in the 3BM utility. Zeroes are written to all unit members. www.3ware.com 49

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Initializing Units
www.3ware.com
49
Initializing Units
Performance of RAID 5 units with 5 or more disks, and RAID 50
units with 10 or 12 disks configured into two subunits will improve
after the unit has been initialized. For these configurations,
foreground initialization (also known as “zeroing”) starts
immediately. If you want to begin using the units right away, you
can halt the zeroing process and initialize them in the background
later, after the operating system is booted. (The initialization
process can take several hours, depending on the size of your
drives.) The disadvantage of initializing the units later in the
background is that the performance RAID 5 and RAID 50 arrays
will be lower until initialization is complete.
Information about initialization for each of the different RAID
types is described below.
RAID 0 Units
RAID 0 units do not need to be initialized and are immediately
available for use with full performance when created.
For RAID 5 and RAID 50 Units
RAID 5 units with 3 or 4 disks do not need to be initialized and are
fault tolerant upon creation. Similarly, RAID 50 units with 6, 8, or 9
disks, and RAID 50 with 12 disks configured into 3 subunits of 4 or
4 subunits of 3, do not need to be initialized. This is because these
configurations use an optimized writing technique which does not
have to be valid to provide fault tolerance.
RAID 5 units with 5 or more disks, and RAID 50 units with 10 or
12 disks configured into two subunits do need to be initialized for
full performance. For these configurations, initialization begins
automatically after you create them in the 3BM utility. Zeroes are
written to all unit members.