disks_info=[{u"diskname": u"/dev/vda", u"disktype": u"HDD", u"tag": [u"mounted", u"boot"], u"slotnum": None, u"rpm": 7200, u"size": 50}, {u"diskname": u"/dev/vdb", u"disktype": u"HDD", u"tag": [u"osd_data"], u"slotnum": None, u"rpm": 7200, u"size": 30}, {u"diskname": u"/dev/vdc", u"disktype": u"HDD", u"tag": [u"osd_data"], u"slotnum": None, u"rpm": 7200, u"size": 30}, {u"diskname": u"/dev/vdd", u"disktype": u"HDD", u"tag": [u"osd_data"], u"slotnum": None, u"rpm": 7200, u"size": 30}, {u"diskname": u"/dev/vde", u"disktype": u"HDD", u"tag": [u"osd_data"], u"slotnum": None, u"rpm": 7200, u"size": 30}, {u"diskname": u"/dev/vdf", u"disktype": u"HDD", u"tag": [u"osd_data"], u"slotnum": None, u"rpm": 7200, u"size": 30}]

disks_info_sorted=sorted(disks_info,key=lambda x:x[u"size"],reverse=True)

print(disks_info_sorted)