Topic
  • 4 replies
  • Latest Post - ‏2014-02-14T12:02:30Z by Emil!
Emil!
Emil!
4 Posts

Pinned topic XIV Disk capacity and system reserved capacity

‏2014-02-11T06:27:34Z |

Hello,

  1. For a XIV array loaded with 2 TB disks, the disk capacity reported by XIV SMI provider (IBMTSDS_DiskDrive.capacity) is 1969889476608 bytes which is lesser than 2 TB.  Could you please explain this difference?
  2. The calculation of 'Net Usable Capacity' of XIV takes 2% as 'System Reserved capacity' in one document whereas it is 4% in another.  Please clarify which is the accurate percentage reserved for System use.  Should this value be hard coded or can it be queried from the provider?
  3. Will the disk type of XIV be SATA across all the models?

Thanks!

  • CHofmeister
    CHofmeister
    11 Posts

    Re: XIV Disk capacity and system reserved capacity

    ‏2014-02-11T21:38:19Z  

    Hi Emil

    1. Sorry I can not say for sure what is going on here, as I have not used the SMI provider yet.
    2. Looking at my 1TB units they have a 4% overhead.  While my 2TB and 3TB units all have 2% overhead.  I am assuming the larger capacity drive, limited how much overhead they needed.
    3. The Gen 3 models offer SAS drives.

    Out of curiosity, are you using a tool, or scripts to pull the SMI data. The XCLI can be slow when running numerous commands, and I have been considering switching to SMI so my data collections run faster.

  • Emil!
    Emil!
    4 Posts

    Re: XIV Disk capacity and system reserved capacity

    ‏2014-02-12T09:02:40Z  

    Hi Emil

    1. Sorry I can not say for sure what is going on here, as I have not used the SMI provider yet.
    2. Looking at my 1TB units they have a 4% overhead.  While my 2TB and 3TB units all have 2% overhead.  I am assuming the larger capacity drive, limited how much overhead they needed.
    3. The Gen 3 models offer SAS drives.

    Out of curiosity, are you using a tool, or scripts to pull the SMI data. The XCLI can be slow when running numerous commands, and I have been considering switching to SMI so my data collections run faster.

    Hi Carl,

    Thank you very much the update.

    Yes, I am using the SMI provider to collect XIV's information.

    Regards. 

     

     

  • Emil!
    Emil!
    4 Posts

    Re: XIV Disk capacity and system reserved capacity

    ‏2014-02-14T11:52:17Z  
    • Emil!
    • ‏2014-02-12T09:02:40Z

    Hi Carl,

    Thank you very much the update.

    Yes, I am using the SMI provider to collect XIV's information.

    Regards. 

     

     

    Hi All,

    Can I get a confirmation on System reserved percentage - is it 2% or 4% or just a rough value between 2-4%?  

    This is blocking my capacity calculations.

    Thanks,

     Emil

  • Emil!
    Emil!
    4 Posts

    Re: XIV Disk capacity and system reserved capacity

    ‏2014-02-14T12:02:30Z  
    • Emil!
    • ‏2014-02-12T09:02:40Z

    Hi Carl,

    Thank you very much the update.

    Yes, I am using the SMI provider to collect XIV's information.

    Regards. 

     

     

    Hi All,

    Can I get a confirmation on System reserved percentage - is it 2% or 4% or just a rough value between 2-4%?  

    This is blocking my capacity calculations.

    Thanks,

     Emil