Values:
TIER_UNSPECIFIED (0):
Not set.
STANDARD (1):
STANDARD tier.
PREMIUM (2):
PREMIUM tier.
BASIC_HDD (3):
BASIC instances offer a maximum capacity of 63.9 TB.
BASIC_HDD is an alias for STANDARD Tier, offering economical
performance backed by HDD.
BASIC_SSD (4):
BASIC instances offer a maximum capacity of 63.9 TB.
BASIC_SSD is an alias for PREMIUM Tier, and offers improved
performance backed by SSD.
HIGH_SCALE_SSD (5):
HIGH_SCALE instances offer expanded capacity and performance
scaling capabilities.