In the vSphere client, the ScratchConfig.ConfiguredScratchLocation is /vmfs/volumes/50de22a5-f4afafa0-f7b5-001517197ad8/.locker
Also, just to let you know I have installed ESXi on a 16GB flash drive.
Here is what I see with those commands:
~ # vdf -h
<snip>
-----
Ramdisk Size Used Available Use% Mounted on
root 32M 412K 31M 1% --
etc 28M 156K 27M 0% --
tmp 192M 4K 191M 0% --
hostdstats 249M 1M 247M 0% --
~ # df -h
Filesystem Size Used Available Use% Mounted on
VMFS-5 596.0G 987.0M 595.0G 0% /vmfs/volumes/640GB_WD_Black_AALS-1
VMFS-5 931.2G 975.0M 930.3G 0% /vmfs/volumes/1TB_WD_Black
vfat 249.7M 130.2M 119.6M 52% /vmfs/volumes/8c231eec-aa4ac1c8-4b1d-14cf7ae5845e
vfat 249.7M 8.0K 249.7M 0% /vmfs/volumes/7cb258e0-f4980796-4918-4766c02ae6a8
vfat 285.8M 201.9M 83.9M 71% /vmfs/volumes/50df4c30-82b86e61-8522-001517197ad8
~ # ls -lh /dev/disks
-rw------- 1 root root 15.0G Jan 1 17:50 mpx.vmhba32:C0:T0:L0
-rw------- 1 root root 4.0M Jan 1 17:50 mpx.vmhba32:C0:T0:L0:1
-rw------- 1 root root 250.0M Jan 1 17:50 mpx.vmhba32:C0:T0:L0:5
-rw------- 1 root root 250.0M Jan 1 17:50 mpx.vmhba32:C0:T0:L0:6
-rw------- 1 root root 110.0M Jan 1 17:50 mpx.vmhba32:C0:T0:L0:7
-rw------- 1 root root 286.0M Jan 1 17:50 mpx.vmhba32:C0:T0:L0:8
-rw------- 1 root root 931.5G Jan 1 17:50 t10.ATA_____WDC_WD1002FAEX2D00Z3A0________________________WD2DWCATR1954950
-rw------- 1 root root 931.5G Jan 1 17:50 t10.ATA_____WDC_WD1002FAEX2D00Z3A0________________________WD2DWCATR1954950:1
-rw------- 1 root root 596.2G Jan 1 17:50 t10.ATA_____WDC_WD6401AALS2D00L3B2________________________WD2DWMASY3506632
-rw------- 1 root root 596.2G Jan 1 17:50 t10.ATA_____WDC_WD6401AALS2D00L3B2________________________WD2DWMASY3506632:1
lrwxrwxrwx 1 root root 20 Jan 1 17:50 vml.0000000000766d68626133323a303a30 -> mpx.vmhba32:C0:T0:L0
lrwxrwxrwx 1 root root 22 Jan 1 17:50 vml.0000000000766d68626133323a303a30:1 -> mpx.vmhba32:C0:T0:L0:1
lrwxrwxrwx 1 root root 22 Jan 1 17:50 vml.0000000000766d68626133323a303a30:5 -> mpx.vmhba32:C0:T0:L0:5
lrwxrwxrwx 1 root root 22 Jan 1 17:50 vml.0000000000766d68626133323a303a30:6 -> mpx.vmhba32:C0:T0:L0:6
lrwxrwxrwx 1 root root 22 Jan 1 17:50 vml.0000000000766d68626133323a303a30:7 -> mpx.vmhba32:C0:T0:L0:7
lrwxrwxrwx 1 root root 22 Jan 1 17:50 vml.0000000000766d68626133323a303a30:8 -> mpx.vmhba32:C0:T0:L0:8
lrwxrwxrwx 1 root root 74 Jan 1 17:50 vml.0100000000202020202057442d574341545231393534393530574443205744 -> t10.ATA_____WDC_WD1002FAEX2D00Z3A0________________________WD2DWCATR1954950
lrwxrwxrwx 1 root root 76 Jan 1 17:50 vml.0100000000202020202057442d574341545231393534393530574443205744:1 -> t10.ATA_____WDC_WD1002FAEX2D00Z3A0________________________WD2DWCATR1954950:1
lrwxrwxrwx 1 root root 74 Jan 1 17:50 vml.0100000000202020202057442d574d41535933353036363332574443205744 -> t10.ATA_____WDC_WD6401AALS2D00L3B2________________________WD2DWMASY3506632
lrwxrwxrwx 1 root root 76 Jan 1 17:50 vml.0100000000202020202057442d574d41535933353036363332574443205744:1 -> t10.ATA_____WDC_WD6401AALS2D00L3B2________________________WD2DWMASY3506632:1