R6 / Capacity lower than physical capacity

  • Last Post 06 February 2019
Tim Finke posted this 05 February 2019

Hi everyone,

we have a promise pegasus R6 with 6 drives à 1 TB so 6 TB in total. The info panel for the locgical drive is showing:

Capacity: 5 TB

Physical Capacity: 6 TB

Since we use the Raid as backup and it happened to be full we would like to use this 1 TB as well. Can anyone help?



PS. We are planning to replace all drives in the future … 

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arunkumar b posted this 06 February 2019

Hi Tim,

Pegasus have default RAID 5 configuration.RAID 5 is data striping with parity.It has one HDD fault tolerance(No data lost if single drive failure).The usable capacity in RAID 5 is Total HDD capacity subtract to one HDD capacity.i,e 6TB-1TB=5TB

If you still want to use total physical capacity 6TB ,you could backup the data from the drive ,delete and recreate the RAID choosing RAID 0 .But, it is not recommended as RAID 0 is disk striping without data redundancy(Data lost if single drive failure)

Please find the below KB article link  for how to create new RAID


Please let me know if you have any queries



Tim Finke posted this 06 February 2019

Hey Arun,

thanks for your help. We already ordered new 3 TB disks in order to replace the existing ones :).

I assume this also is done by creating a new array, right?

Thanks again and best regards,