Promise Technology M500p, M500i, M500f Ranges of Disk Array Expansion, Create a New Logical Drive

VTrak M-Class Product Manual

Ranges of Disk Array Expansion

There are limitations to how large you can expand a disk array, depending on the size of your current disk array.

The current iSCSI, SCSI, and Fibre Channel HBA cards and PC Operating Systems support a 10-byte LBA format. This means that a disk array can have up to 4 billion address blocks or sectors.

Multiply the number of blocks by the sector size to find the capacity of a disk array:

4,000,000,000 blocks x 512 bytes per sector = 2,048,000,000,000 bytes of data for a 2TB drive.

Note that you cannot change the size of the sectors nor can you increase the number of address blocks above 4 billion.

As a result, there are range limits imposed upon disk array expansion as shown in the table above. For example:

•You can expand a 2.5 TB disk array up to 4 TB

•You can only expand a 1.9 TB disk array up to 2 TB

See the chart below.

Current LD Size	Maximum LD	Sector Size
	Expansion Size
8 to 16 TB	16 TB	4096 bytes
4 to 8 TB	8 TB	2048 bytes
2 to 4 TB	4 TB	1024 bytes
0 to 2 TB	2 TB	512 bytes

You can direct WebPAM to expand a logical drive beyond the maximum expansion size. When the expansion is finished, WebPAM will show the logical drive in the desired size. However, your operating system might show the logical drive at the maximum expansion size (listed in the table above) and the rest of the capacity as unformatted disk space.

At this point, you can:

•Format the disk space, which results in a second logical drive

•Create a new logical drive. See below

Create a New Logical Drive

To create a new logical drive:

1.Backup the data from the current logical drive.

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