Trident - Snapshots and Quiescing

[bcoy]

How does DB quiescing work within a container using Trident?

[olivpass]

Hi bcoy,

do you have an answer for this?

i have an idea how to do this, but it is not fully ready:

* it is possible to create a snapshot and a new volume from a volume with one docker command:
** docker volume create --driver drivername --name volume_name_quiesced_snap -o from=volume_name

The flow to get a quiesed snapshot will this:

1 quiesce the db

2 docker volume create --driver drivername --name dbvolume_name_quiesced_snap -o from=dbvolume_name

3 unquiesce the db

[elementx]

It works the same way as with VMs and bare metal servers, i.e. the snapshot feature doesn't do it.

Like with the other two you need to quiesce the DB if you want transaction-consistent snapshots, or just ignore the quiesce step and use crash-cosnistent snapshots.

Some people say crash-consistent snapshots aren't reliable, but if your database cannot survive OS crash, maybe you should change or upgrade your database application...