Bug 1226367

Summary:	[doc] Issue in "Creating a clustered MD RAID device"
Product:	[openSUSE] PUBLIC SUSE Linux Enterprise High Availability Extension 15 SP5	Reporter:	Jiri Belka <jiri.belka>
Component:	Documentation	Assignee:	Tahlia Richardson <tahlia.richardson>
Status:	RESOLVED FIXED	QA Contact:	Tanja Roth <taroth>
Severity:	Normal
Priority:	P5 - None	CC:	jiri.belka
Version:	unspecified
Target Milestone:	---
Hardware:	Other
OS:	Other
URL:	https://jira.suse.com/browse/DOCTEAM-1466
Whiteboard:
Found By:	---	Services Priority:
Business Priority:		Blocker:	---
Marketing QA Status:	---	IT Deployment:	---
Attachments:	screenshot

Description Jiri Belka 2024-06-14 14:43:21 UTC

Creating a clustered MD RAID device:

https://documentation.suse.com/sle-ha/15-SP5/single-html/SLE-HA-administration/#sec-ha-cluster-md-create

Hi, since I got a customer case about cluster MD, please improve this part:

- original:

For better stability, use persistent device names such as /dev/disk/by-id/DEVICE_ID instead of /dev/sdX names.

- new proposal:

Use must use cluster-wide persistent names, eg. /dev/disk/by-id/xxxx; note that /dev/sdX and also /dev/dm-X are not stable names through the whole cluster; doing array management operation with non-deterministic names (eg. /dev/sdX or /dev/dm-X) can lead to catagrophic consequences.

Cf. https://en.opensuse.org/SDB:SCSI_Device_Identification
    https://www.suse.com/support/kb/doc/?id=000018449

The main message here is - dm-X is not stable too!

I hope you understand; you know better wording. Thank you very much.

Comment 1 Jiri Belka 2024-06-14 14:43:41 UTC

And, maybe a warning box for this for better visibility???

Comment 2 Jiri Belka 2024-06-14 14:44:23 UTC

Created attachment 875492 [details]
screenshot

Comment 3 Tahlia Richardson 2024-06-18 05:15:25 UTC

Thanks Jiri, I agree it makes sense to be as clear as possible there! 

I've added it to our queue and will make sure to get to it quikcly.

Comment 4 Tahlia Richardson 2024-06-19 06:16:51 UTC

What do you think of this?

---
Warning: Always use persistent device names

Always use cluster-wide persistent device names, such as /dev/disk/by-id/DEVICE_ID. Unstable device names like /dev/sdX or /dev/dm-X might become mismatched on different nodes, causing major problems across the cluster. 
---

Here's the PR: https://github.com/SUSE/doc-sleha/pull/393

Comment 5 Jiri Belka 2024-06-19 06:41:35 UTC

(In reply to Tahlia Richardson from comment #4)
> What do you think of this?
> 
> ---
> Warning: Always use persistent device names
> 
> Always use cluster-wide persistent device names, such as
> /dev/disk/by-id/DEVICE_ID. Unstable device names like /dev/sdX or /dev/dm-X
> might become mismatched on different nodes, causing major problems across
> the cluster. 
> ---
> 
> Here's the PR: https://github.com/SUSE/doc-sleha/pull/393

cool; thank you.

Comment 6 Tahlia Richardson 2024-06-21 01:01:40 UTC

This is now merged and backported, and will be published with the next weekly docs update.