What is consistency group

For example, you can create a consistency group if you want to take a synchronized snapshot image of several volumes that are in different volume groups or disk pools in a storage array. Using the consistency group mechanism is ideal for applications that span multiple volumes, for example, a database application that has the logs on one volume and the database on another volume.

Each base volume that belongs to a consistency group is referred to as a "member volume. When you create a consistency group, the storage management software lets you add member volumes during the creation process or create the consistency group with no member volumes. If you want to add member volumes as part of the creation process, you select the desired volumes from the eligible volumes list and select the automatic or manual member repository creation option. It may be a UPS that can keep disks running for long enough to destage the cache during a power failure, it may be a NVRAM write cache that can withstand power loss, or it may be a simple battery on the volatile RAM that will last for a few days.

Sign up to join this community. The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more. What are storage consistency groups? Ask Question. Asked 5 years, 7 months ago. Active 5 years, 7 months ago. Viewed 6k times. It seems every vendor has its own proprietary terminology for storage features, but here's what I could gather so far: A consistency group is I think a bunch of storage volumes that promise to always be consistent, that is, no single volume will ever be in a further point-in-time than its peers.

Now, what I don't get, nor can I find anywhere else is: 1 - Is the consistency of the Consistency Group between all volumes of the same group or only between each volume and its respective mirror somewhere? Thank you. Improve this question. Add a comment. Active Oldest Votes. Enabling Protection For Secondary Resource Of Consistency Groups This operation enables protection for secondary resource of all remote replication pairs in consistency group, and the data of secondary resource cannot be written to ensure the security of the data from the secondary resource.

Disabling Protection For Secondary Resource Of Consistency Groups This operation disables protection for secondary resource of all remote replication in consistency group, and the data of secondary resource can be written again.

Adding a Remote Replication Pair This operation enables you to add a remote replication pair to a consistency group. This ensures that the data of secondary resource of added pair is consistent with that of other pairs in the group at the same point in time.