SCSI-3 persistent reservations on Linux guests?

[joe_nuspl]

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I'm trying to create a Linux cluster-in-a-box under ESX 4.0.0-164009...

Following the instructions laid out in ,

I configured a Linux VM with a “virtual” shared mode SAS controller and created a thick vmdk with "support clusterning features" enabled. I can see the disk but when I try the SCSI-3 PR test that comes with sg3_utils, it fails…

1. ./sg_persist_tst.sh /dev/sdb

&gt;&gt;&gt; try to report capabilities:

VMware Virtual disk

1.0

Peripheral device type: disk

PR in: bad field in cdb including unsupported

service action

illegal request, report capabilities not

supported?

&gt;&gt;&gt; check if any keys are registered:

VMware Virtual

disk 1.0

Peripheral device type: disk

PR generation=0x0, there are NO registered

reservation keys

&gt;&gt;&gt; register a key:

PR out: bad field in cdb including unsupported

service action

&gt;&gt;&gt; now key 123abc should be registered:

PR generation=0x0, there are NO registered

reservation keys

&gt;&gt;&gt; reserve the device (based on key

123abc):

PR out: bad field in cdb including unsupported

service action

&gt;&gt;&gt; check if the device is reserved (it

should be now):

PR generation=0x0, there is NO reservation

held

&gt;&gt;&gt; now release reservation:

PR out: bad field in cdb including unsupported

service action

&gt;&gt;&gt; check if the device is reserved (it

should not be now):

PR generation=0x0, there is NO reservation

held

&gt;&gt;&gt; unregister key 123abc:

PR out: bad field in cdb including unsupported

service action

&gt;&gt;&gt; now key 123abc should not be

registered:

PR generation=0x0, there are NO registered

reservation keys

So

it appears that the SCSI-3 persistent reservation commands, PRIN and PROUT, are

not supported but MSCS 2008 requires them… Is there an ESX host setting that

needs to be configured?

Thanks.

Joe

[dilidolo]

What storage do you use? Does your storage support SCSI-3 persistent reservation?

[joe_nuspl]

It is DAS. The underlying storage is SATA which does not supported PR. However, for virtual disks the under lying storage should not matter. Since PR occurs at the LUN level, one would have to have separate LUNs for each shared vmdk.

Under Prerequisites in Chapter 3: "Cluster Virtual Machines Across Physical Hosts" it lists:

Fibre Channel (FC) SAN. Shared storage must be on an FC SAN.

Chapter 2: "Cluster Virtual Machines on One Physical Host" lists no such requirement. So is DAS not supported?

Joe

[mcowger]

Well, for 1 you need physical mode RDMs to do reservations.

Second, you will need a proper array of some sort (iSCSI or FC)

--Matt

VCP, vExpert, Unix Geek

[joe_nuspl]

According to page 19, this is true for cluster nodes across physical hosts. However, the instructionson page 15 state:

2 Click Add, select Hard Disk, and click Next.

3 Select Create a new virtual disk and click Next.

4 Select the disk size.

5 Under Disk Provisioning, select Support clustering features such as Fault Tolerance.

You can also use a mapped SAN LUN set to virtual compatibility mode.

So are the instructions in http://www.vmware.com/pdf/vsphere4/r40/vsp_40_mscs.pdf wrong?

Joe