Volume Size & Extent

[Faisal Sharif]

Hello All ,

i am a new guy here so forgive me if i am unclear and ask a stupid question , so here is the problem

i configured freNAS successfully , with a volume of 30 GB
and then i created an extent of 100GB

i connected to FreeNAS Successfully from a windows 7 machine and the drive was also formatted successfully and it show 100 GB but am confused here

Volume of 30 GB AND Extent of 100 GB ? Confused really

What's gonna happen when i reach 30 GB actual size of that volume

Please explain if i am unclear or point me to somewhere


Thanks in Advance..

 

[cyberjock]

Suddenly you'll have an extent that is "read-only" and probably has a fubared file system, and you'd likely be locked out of the data stored in the extent.

The example you provided is precisely the kind of thing that a good admin should not be allowing to happen. So good on you for identifying that you can shoot yourself in the face. :)

So don't do that because it's bad. ;)

 

[Faisal Sharif]

Thanks Brother


I GOT IT NOW ....... was trying this for the first time so expect funny you know ;)

 

[mav@]

I am not sure I understand your terminology of volume and extent. But if my guess is right and 30GB is your ZFS pool size and 100GB is iSCSI extent size, then your configuration is technically not incorrect, just not very typical -- it is called storage overprovisioning. If you used ZVOL-based extent (not file-based) and your initiator OS supports SCSI UNMAP, then your configuration should be able to live happily as long as you don't store more then ~25GB at a time to that extent. If your data are well-compressible, then you may store even more then that. But definitely such configuration requires additional care to not create problems.