The host will see the total amount. Since this is a thin environment, the total capacity of the device does not need to be allocated in the thin pool. That is one of the major benefits of thin technology. When the device is created, you have the option to determine how much storage is actually allocated in the pool. this can be anywhere from 0 to 100% and this will be reflected in the Allocated GB. Even if the allocated GB was 100%, by running a RECLAIM on the device (to free all the allocated but unused capacity), the Allocated amount will be reduced.  The x flag suggests that this device has allocations across multiple pools. Since you are only looking at one pool in your command, this may another reason why the numbers are not working for you. Try symcfg -sid xx list -tdev -gb -detail. This will give multiple lines of output for each device that has allocations across multiple pools.
hello,  can someone please explain the differance between total GBs vs Total allocated GBs below ? because we are noticing lun size discrepancy on vm hosts.  Here 0154 tdev original size is 1923 .8but what is 1806.3 ? Also do the host see 1923.8gb or 1806.3 ?   $ symcfg -sid xxx list -tdev -gb -thin -pool xxxxx  Symmetrix ID: xxxx  Enabled Capacity (GBs) :    xxx Bound   Capacity (GBs) :    xxx                   S Y M M E T R I X   T H I N   D E V I C E S ------------------------------------------------------------------------------                                                                    Total          Total       Compressed        Bound             Flgs                Total       Allocated       Written      Size/Ratio Sym  Pool Name    EMPT               GBs        GBs (%)        GBs (%)        GBs (%) ---- ------------ ---- ---------- ---------- --- ---------- --- ---------- --- 0154   xxxxxx           FX.B            1923.8     1806.3  94     1699.7  88     1806.3   0   Appreciate any help.  thanks, Raj
Tdev size - total vs total allocated