How to calculate the total space of the disk domain for S5500T V2 device

Publication Date:  2015-12-12 Views:  298 Downloads:  0
Issue Description

There are 20 disks in the same disk domain, 10 disks with 2TB and the other 10 disks with 4TB.

After creating the disk domain, the displayed capacity is as below: (the logical capacity should be about 54TB, here there is only 36TB)

Solution

We have the mechanism for the physical disk space and available space after creating disk domain as below:

1.      When you create a disk domain, our storage system will follow the principle below to create disk group

Put the disks in the disk domain in descending order by capacity

Select first 11 disks to create the first disk group,

Then select the next 22 disks to create the second disk group, if the left disks are less than 22, then all of them are put in one disk group,

Then select the next 33 disks to create the third disk group, if the left disks are less than 33, then all of them are put in one disk group,

……

2.  For the disks in one disk group, system will regard the smallest disk as basis to create available capacity, for other disks, if their capacity is larger than the basic disk, the extra capacity will be cut off, which is why the total available capacity smaller than the total logical capacity in this case.

3.  For current case, we can add one 4TB disk in the disk domain, after adding it, system will automatically put it in the first disk group due to the capacity is larger than 2TB. 

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