In all the lab setups we have created, the system uses 74gb, which is also verified by the TMSH df -h.
On the resource provisioning, it shows that disk space is only 24 gb, which corresponds to the 25 gb in the appdata, but tmsh shows that 19% is used while resource provisioning shows that almost 99% is used.
I havent been able to understand this, nor fix this by expanding the disk space
74GB is the whole disk. BIG-IP uses Linux Logical Volume Manager (LVM) to create the logical volumes (LVs) for the software (aka boot locations), and shared volumes such as appdata.
You can see the Physical Volume with the "pvs" command. You will see it is approx 74GB.
[admin@bigip:Active:Standalone] ~ # pvs PV VG Fmt Attr PSize PFree /dev/sda3 vg-db-vda lvm2 a-- 75.79g 9.17g
This is also the size of the one Volume Group ("vgs" command). Note there is some free space, not allocated to any logical volume.
[admin@bigip:Active:Standalone] ~ # vgs VG #PV #LV #SN Attr VSize VFree vg-db-vda 1 13 0 wz--n- 75.79g 9.17g
Within the volume group are the logical volumes ("lvs" command) which contain the actual filesystems, including the 25GB "appdata" volume:
[admin@bigip:Active:Standalone] ~ # lvs LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert dat.appdata vg-db-vda -wi-ao---- 24.92g dat.log vg-db-vda -wi-ao---- 2.93g dat.maint.1 vg-db-vda -wi-a----- 300.00m dat.share vg-db-vda -wi-ao---- 15.00g dat.swapvol vg-db-vda -wi-ao---- 1000.00m set.1._config vg-db-vda -wi-ao---- 2.17g set.1._usr vg-db-vda -wi-ao---- 5.15g set.1._var vg-db-vda -wi-ao---- 3.00g set.1.root vg-db-vda -wi-ao---- 440.00m set.2._config vg-db-vda -wi-a----- 2.17g set.2._usr vg-db-vda -wi-a----- 5.15g set.2._var vg-db-vda -wi-a----- 4.00g set.2.root vg-db-vda -wi-a----- 440.00m
(Those set.1 and set.2 volumes are the Boot Locations HD1.1, HD1.2.)
The 99% of 24GB disk space shown in Resource Provisioning is the estimated maximum space your modules may grow to need. In theory they should manage themselves to remain under that size. (In practice, in some extreme cases they may not.)
The 19% is how much of the appdata filesystem they are currently using. 19% used is quite healthy, and I would not be worried. You should have logging to look out for logs from diskmonitor should any volume's used space cross thresholds.
Clearly from the logical volumes above you can see there is lots more space in the 74GB PV to grow. You can use that space for additional Boot Locations (as simply as typing a new number for Volume set name when installing a software image), or if you did need to grow appdata you can do that using "modify /sys disk directory /appdata" tmsh commands. (Note that you can only increase the size, not shrink it, so be sure this is what you want.)