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Why is that? Preservation capacity on the MD3620i

Within disk pool (DDP) thin volumes have been created.  

When the disk pool is created 2 disk are automatically assigned for preservation capacity.
Total capacity:
5,404.000 GB
Preservation capacity:
1,112.000 GB(2 Physical Disks)
Usable capacity:
4,292.000 GB
Unusable capacity:
0.000 MB


But as volumes are added the storage manager keeps asking to add preservation capacity to each volume for rebuilding operation.  I don't get it.   Please help me to clear the things up here I should have missed something.  

from Dell documentation:

Preservation Capacity – This attribute specifies the number of drives to reserve
in a disk pool for the reconstruction process in addition to the reserved
reconstruction space reserved on each drive. The default for this parameter is 1.
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quadrumane
Asked:
quadrumane
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1 Solution
 
agonza07Commented:
Think about it as your spare drives in order to recover from a failed RAID drive.


Configuring The Preservation Capacity Of A Disk Pool
 
The preservation capacity in a disk pool is reserved for data reconstruction operations in case of physical disk failures.
 
To configure the preservation capacity in a disk pool:
 
1. In AMW, select the Storage & Copy Services tab.
 2. Select the disk pool.
3.From the menu bar, select Storage ¿ Disk Pool ¿ Change ¿ Settings.
 The Change Disk Pool Settings dialog is displayed.
 4.In the Preservation Capacity area of the Physical disks dedicated to preservation capacity box, type or select a number of physical disks.
 
The preservation capacity of the disk pool is dependent on the number of physical disks in the disk pool.
 5.Click OK.
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quadrumaneAuthor Commented:
The default settings on the MD would take as much as almost half the available capacity for this "hot spare drives".   As far as I know conventional RAID models don't have 6 or 7 hot spares.
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agonza07Commented:
From your quote on the original posting the default is 1 drive.

And from your original comment it's only taking up 2.

Not sure where you are getting 6 or 7, but please post a screenshot or configuration settings of what you mean. Make sure to include your current RAiD config.
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