I’m a bit confused with the space some volumes are reporting.
- 710Gb Volume (Fractional Reserve 20% / Snap Reserve 0)
- The volume contains a 460Gb lun of which 452GB is being used.
- My snapshots report 117 Gb used
Therefore I would expect space used by the volume to be
Volume – Lun used size – FractionalReserve - SnapShot Used
710 – 452 – 142 – 117 = -1
The volume actually reports 669Gb used and 41Gb free?
So from the figures above resulting in -1, I'm assuming that I'm using some of my Fractional Reserve for snapshots, however each snapshot is only about 15gb so I would expect the volume available space to get to 0 before Fractional Reserve starts being used. I can't see how you can see how much of the Fractiona Reserve is actually being use.
I’m sure I’m doing something wrong but just can’t see it.
Solved! See The Solution
2 REPLIES 2
2011-09-14 04:23 AM
The Fractional reserve is a setting for how important it is for the snapshot of this LUN to be able to be created. Set it to 20% and it will "reserve" 20% of the size of the LUN to "guarantee" the creation of a snapshot that needs 92G of space. If you create a snapshot that nedds more space then 92G, it will fail...
Try this math:
vol = 720G
LUN = 460G
free1 = 260G
snap used = 117G
free2 = 143G
Fractional = 92G (20% of 460G)
free3 = 51G
space used = 460 + 117 + 92 = 669
Hope this helps,