[Linux-cluster] SCSI-fence configure

[Ryan O'Hara]

m.. mm.. wrote:
> Hi Ryan or somebody else..
> 
> I have one question about your documentation about RedHat and scsi_reservation fence what you have write.
> 
> About this Storage Requimenents:
> You write like this. "all shared storage must use LVM2 cluster volumes"
> If i have 2 cluster-nodes and shared /data1 mount which are this shared volume, with no scsi-resevation bit on, in active-passive mode service.
> And i want SCSI-fence like: I configure 2 * 2Gb shared storage more with SCSI-3 reservation bit on and create lvm2-partition, should this fence work, or must i still convert this allready configured /data1 to lvm2, for not preventing data-corruption in some situations. Or can i leave this partition unchanged

This means you must use LVM2 to setup your shared storage. In other 
words, you must be using clvmd (lvm2-cluster package).

Also note that active-passive arrays are not officially support. I have 
tested as active-passive array with RHEL5 and it seems to work due to a 
change in device-mapper-multipath. The reason is that SCSI reservations 
work by using an ioctl call to the devices and both the active and 
passive paths must get this ioctl (to create the registration and/or 
reservation). RHEL5 appears to include a fix that passes this ioctl to 
all devices. This is not present in RHEL4. I believe the documentation 
states that active-passive (multipath) arrays are not supported. I will 
update this when I do more testing.

I'm not sure what you mean by "no scsi-resevation bit on". Can you explain?

-Ryan


> ------------cut starts:--------------
> 3.2 - Storage Requirements
> 
> In order to use SCSI persistent reservations as a fencing method, all
> shared storage must use LVM2 cluster volumes. In addition, all devices
> within these volumes must be SPC-3 compliant. If you are unsure if
> your cluster and shared storage environment meets these requirements,
> a script is available to determine if your shared storage devices are
> capable of using SCSI persistent reservations. See section x.x.
> 
> ------------ cut ends-------------------------------
> 
> 
> 
> 
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