When trying to attach iscsi device from my storage system, ovirt complains, that it cannot create a storage pool. 

In logs I can see only this:

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RuntimeError(u'Error creating a storage pool: (u"spUUID=3fcace71-cd2b-4ab4-9d64-8ef926ead05a, poolName=hosted_datacenter, masterDom=71b0d510-c24a-49fa-86ec-6b5ebf530140, domList=[u\'71b0d510-c24a-49fa-86ec-6b5ebf530140\', u\'793985b7-9d11-44a4-bf68-4b509a967a52\'], masterVersion=1, clusterlock params: ({\'LEASETIMESEC\': 60, \'LOCKPOLICY\': \'ON\', \'IOOPTIMEOUTSEC\': 10, \'LEASERETRIES\': 3, \'LOCKRENEWALINTERVALSEC\': 5})",)',), <traceback object at 0x35935a8>)

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I have verified, that this block device can be successfully connected and partitioned on the same server using standard tools (iscsiadm, parted, mount), so, storage system on its own is working fine.

My question is: what are requirements for block device in order for it to be compliant with ovirt? I know, that block size must be 512 bytes, but anything else?

Thank you in advance, any comments appreciated.

 Sergei.