topic Re: OS 5.2 Replication type Synchronous and Partner not showing in Volume Collection in Array Setup and Networking

OS 5.2 Replication type Synchronous and Partner not showing in Volume Collection

Fred Blum — Tue, 07 Jul 2020 20:35:33 GMT

We have upgraded to 5.2. I have set cli command ""group –edit –default_iscsi_target_scope group". I created a new volume and saw LUN 0 added.. There are still existing volumes for which I need to schedule downtime in order to unexport them and change the initiator.

When I try to create a new volume collection it does not show Replication type "Synchronous" and Replication Partner.

I do not understand why not. Only volumes that are GST should be able to be added to this Volume Collection.

Am I missing something?

TIA,

Fred

Re: OS 5.2 Replication type Synchronous and Partner not showing in Volume Collection

Nick_Dyer — Tue, 07 Jul 2020 21:07:12 GMT

Fred,

probably worth a quick call to Nimble Support to get you up and running.

Re: OS 5.2 Replication type Synchronous and Partner not showing in Volume Collection

Fred Blum — Wed, 08 Jul 2020 09:25:29 GMT

First response from support was that they don't know the procedure I am trying to perform to get an existing group and volumes to perform sync replication and after installation of the witness to peer persistance (automatic failover). I have refered them to the HPE Peer Persistance Deployment Guide and https://newman.cloud/en/2019/05/28/sync-replication-and-peer-persistence-setup-hpe-nimble/

I now have one GST Volume with the Group Initiator and three existing VST volumes with the volume inititiator. From what I understand the synchornous replication is set tru creating a volume Collection, but the synchronous replication option is not visible in the create Volume Collections screen in my OS 5.2.

Regarding the witness.

5. Witness installation. As mentioned before, this is optional and required only if we ant ASO (Automatic SwitchOver), which is automatically brings the Peer Persistence synchronously replicated volume to “active” state on the surviving array. If manual failover is enough this can be skipped. Currently witness is an RPM file, which can be downloaded from HPE Infosight and can be installed on a CentOS machine (minimum 7.2). Later there will be an appliance for this, but not yet public. Important to open up firewall – if there is any – as arrays’ management IP should reach it over port 5395.

From your blog:

- If using Automatic Switch Over (ASO) for application transparent failover, the witness client will need to be located in a third failure domain. Look for this to be offered as a service using a cloud closer to HPE's heart in the future...

Any news when this service will be available?

Regards,

Fred

Re: OS 5.2 Replication type Synchronous and Partner not showing in Volume Collection

Nick_Dyer — Wed, 08 Jul 2020 09:54:29 GMT

Fred,

That doesn't sound like a typical Nimble Support response - what is the support case number please?

Yes - you will find sync replication as an option under your volume collection once you've grouped your two arrays together, with two different pools, and have them showing as pool partners (upstream/downstream).

Are your volumes that you're also trying to synchronously replicate set to be GST rather than VST?

Within NimbleOS 5.2 - the witness now is available as an OVF for you to deploy anywhere you see fit, it doesn't have to be an RPM which you have to maintain on a homebrewed Linux build.

Cloud witness as a Service is coming.... but nothing to update at this time.

Re: OS 5.2 Replication type Synchronous and Partner not showing in Volume Collection

Fred Blum — Wed, 08 Jul 2020 11:06:11 GMT

Hi Nick,

Are there additional settings related to the pool partners that need to be set for sync repl?

These were automatically created before setting Group in the CLI for new volumes and can therefor not be removed to recreate them. Are there additional settings that need to be set or changed tru the CLI?

My problem is this:

There is no replication type and replication partner to be used.

case 03746544.

Regards,

Fred

Re: OS 5.2 Replication type Synchronous and Partner not showing in Volume Collection

Nick_Dyer — Wed, 08 Jul 2020 11:37:19 GMT

Fred,

i just remembered you're on NimbleOS 5.2 - the replication type has moved to being part of the schedule of your volume collection, as we now support fan-out 3DC replication (not with synchronous yet, but coming soon).

Do you see this (similar to my screenshot?)

Also i see that Nimble Support are working with you remotely to resolve too.

Re: OS 5.2 Replication type Synchronous and Partner not showing in Volume Collection

Fred Blum — Wed, 08 Jul 2020 12:22:12 GMT

Thanks Nick,

I found it. I see how it was double in a sense but it also seems counter intuitive moving it that way especially with regards to setting a schedule for snapshots and a setting under replication type synchronous as replicate after every 1 snaphot.

Synchronous should always be what it says, always on replication = synchronous replication.

How are we to interpret this setting Replicate after 1 snapshot in regards to synchronous? Shouldn't it dissapair with synchronous? Or should it read Replicate snapshots after every 1 snapshot?

Thanks again,

Fred

Re: OS 5.2 Replication type Synchronous and Partner not showing in Volume Collection

Sheldon Smith — Wed, 08 Jul 2020 12:59:49 GMT

Periodic Snapshots provide protection from external volume corruption (for example, ransomware). Something damages the upstream volume, synchronous replication will carefully replicate that corruption to the downstream volume. It's rather nice to be able to promote a good earlier snapshot pair just in case.

You can still have hourly and daily or whatever snapshots for rollback insurance. And for any policy or even legal reasons.

Re: OS 5.2 Replication type Synchronous and Partner not showing in Volume Collection

Nick_Dyer — Wed, 08 Jul 2020 20:04:12 GMT

Indeed. taking local and remote snapshots are highly recommended, and give you an extra safety net should something go awry (hopefully not). Snaps have no performance overhead and are very space efficient.

Even if you DONT take snapshots on volumes, NimbleOS will take hidden hourly snapshots for you for that proverbial safety net.... but you need to speak with Support to restore data from them.

Re: OS 5.2 Replication type Synchronous and Partner not showing in Volume Collection

Sheldon Smith — Wed, 08 Jul 2020 20:20:44 GMT

Just be aware there's only one hidden hourly snapshot per volume. It might be a very small window to get Support to restore that data.