Bug 236576
| Summary: | Scant information regarding SCSI bus scanning and devices hot adding/removal | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Linux 4 | Reporter: | Aleksander Adamowski <bugs-redhat> |
| Component: | Documentation | Assignee: | Don Domingo <ddomingo> |
| Status: | CLOSED NOTABUG | QA Contact: | John Ha <jha> |
| Severity: | medium | Docs Contact: | |
| Priority: | medium | ||
| Version: | 4.4 | CC: | adstrong, tao, wmealing |
| Target Milestone: | --- | Keywords: | Documentation |
| Target Release: | --- | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | Bug Fix | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2008-01-29 04:27:07 UTC | Type: | --- |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
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Description
Aleksander Adamowski
2007-04-16 15:16:02 UTC
Any updates on this? Hotplugging of disk drives is a pretty basic expectation from an enterprise grade OS... Gday, This is a more complicated matter than the kbase covers. I'll reply to your comments in line. > Both of them specify that the operation isn't guaranteed to work Correct, as many drivers, such as third party modules can influence how this works. Multipathing and fiber switches between the storage and the host machine may influence the ability to be able to reliably hot add devices. > not corrupt data. If you have a pending scsi write to a device on the chain, you issue a scsi reset down the chain while the device is pending a write() or a read(), there is no guarantee that this data will be synced to the disk before the scsi device reset is done. It is also possible that multiple host controllers are connected to a single scsi bus chain (not common, but it has been seen in production) rescanning the bus which is initiated by a single controller will cause the other scsi bus controller to reset, losing possible writes queued on the controllers internal buffers. > This information isn't satisfactory for corporate RHEL customers. > E.g. our customer (who has quite a large RHEL deployment) has a IBM x346 > production server with SerweRAID 7k controller running RHEL4U4 and needs to > hot-add a SCSI drive. I would strongly reccomend that you test this kind of change to your server infrastructure on your staging systems first before deploying to your production systems, testing testing and more testing. If you feel that this is a feature that you'd like to see in Red Hat Enterprise Linux, please contact Red Hat Support (or your TAM ) and raise a feature request citing this bugzilla. I think it would be a good idea to copy-paste your explanation into the kb articles in question since this makes some things more clear and is a good thing. That said, you explanation covers problems with multipathing and shared storage installations. What about a simple case where the device is simply hot-added to a dedicated box, and all devices on the SCSI chain are idle at the moment (e.g. all services are stopped and filesystems are synced)? Whatever the answer, it would be a good idea to add more info to kb to clarify things. Removing automation notification question satisfactorily answered by wmealing. as for suggestion re: kbase, please use the rating buttons (i.e. "How well did this entry answer your question?") to notify the specific kbase writer. closing this bug as NOTABUG. |