Note: This bug is displayed in read-only format because
the product is no longer active in Red Hat Bugzilla.
RHEL Engineering is moving the tracking of its product development work on RHEL 6 through RHEL 9 to Red Hat Jira (issues.redhat.com). If you're a Red Hat customer, please continue to file support cases via the Red Hat customer portal. If you're not, please head to the "RHEL project" in Red Hat Jira and file new tickets here. Individual Bugzilla bugs in the statuses "NEW", "ASSIGNED", and "POST" are being migrated throughout September 2023. Bugs of Red Hat partners with an assigned Engineering Partner Manager (EPM) are migrated in late September as per pre-agreed dates. Bugs against components "kernel", "kernel-rt", and "kpatch" are only migrated if still in "NEW" or "ASSIGNED". If you cannot log in to RH Jira, please consult article #7032570. That failing, please send an e-mail to the RH Jira admins at rh-issues@redhat.com to troubleshoot your issue as a user management inquiry. The email creates a ServiceNow ticket with Red Hat. Individual Bugzilla bugs that are migrated will be moved to status "CLOSED", resolution "MIGRATED", and set with "MigratedToJIRA" in "Keywords". The link to the successor Jira issue will be found under "Links", have a little "two-footprint" icon next to it, and direct you to the "RHEL project" in Red Hat Jira (issue links are of type "https://issues.redhat.com/browse/RHEL-XXXX", where "X" is a digit). This same link will be available in a blue banner at the top of the page informing you that that bug has been migrated.
In the Storage Admin guide, anywhere that we reference the '--device' argument for VDO, we need to make sure it is clear that whatever value is provided can change, and so the admin should use a persistent device name (such as /dev/disk/by-id/scsi-3600508b1001c264ad2af21e903ad031f, or /dev/disk/by-id/ata-WDC_WD1002FBYS-02A6B0_WD-WMATV6390411)
My below suggestions are against the Quick Start Guide. The Integration Guide may also need some attention.
========================================
SUGGESTED TEXT FOR DOC BELOW
The text should say something like (original suggestion can be found in https://bugzilla.redhat.com/show_bug.cgi?id=1540619#c15):
"If you use a non-persistent device name, then VDO may fail to startup properly in the future if the device name changes. It is recommended that you use a persistent device name." And then include an example like what I posted above.
SUGGESTED TEXT FOR DOC BELOW
========================================
Using https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html-single/storage_administration_guide/index#vdo-quick-start as the base:
Under 28.4. Creating a VDO Volume, there should be an 'Important' block with the quoted text above.
Example 28.1 specifies /dev/sdb, it should probably be modified to use one of the examples in the initial description (preferably the /dev/disk/by-id/scsi-3600508b1001c264ad2af21e903ad031f value, as that is more generic and doesn't suggest using an HDD or flash)
There may need to be a pointer that helps the user find the persistent name for the device they are using. If they run 'ls -l /dev/disk/by-id' they can find the associated device they are intending.
Example: 'ls -l /dev/disk/by-id/scsi-3600508b1001c264ad2af21e903ad031f' shows that it refers to '/dev/disk/by-id/../../sda' (or more simply, /dev/sda)
The testing done in the Evaluation guide is not meant to be a permanent implementation of VDO. The point of specifying a persistent device is to make sure your production workload doesn't all of a sudden end up with the backing device(s) moving to a different name upon a reboot. With that in mind, I don't think it is necessary to recommend persistent device names for the VDO volume.