Confusion on disk types in gcloud when creating a new disk
Your choices are:
- local SSD = locally-attached to the VM, SSD
- standard persistent = network-attached, persistent, HDD**
- SSD persistent = network-attached, persistent, SSD
Type 1 is lower latency than types 2 and 3, because type 1 is physically attached to the VM.
Type 2 and 3 persist beyond instance stop/delete. Type 1 does not.
Type 2 and 3 are durable/redundant (Google replicates them, like Raid 1). Type 1 is not.
Type 2 and 3 can be attached to multiple VMs simultaneously (in read mode). Type 1 cannot.
** nowhere does Google actually indicate afaik that standard persistent is actually HDD, just that it is not SSD, so it may not be guaranteed to be HDD.
You can see more specific data at Storage Options, but in summary:
- local SSD is the fastest (by far)
- SSD persistent has much higher read/write IOPS than standard persistent
- SSD persistent is more expensive (4x) than standard persistent