Term
| Name the three different types of device identifiers used to make up part of the storage naming convention. |
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Definition
| SCSI inquiry identifiers, Path-based identifier, Legacy identifier |
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Term
| How do SCSI inquiry identifiers work? |
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Definition
The host uses the SCSI INQUIRY command to query a storage device and uses the resulting data, in particular the Page 83 information, to generate a unique identifier. Device identifiers that are based on Page 83 are unique across all hosts, persistent, and have one of the following formats:
■ naa.number
■ t10.number
■ eui.number
These formats follow the T10 committee standards. See the SCSI-3 documentation on the T10 committee Web site. |
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Term
| How do path-based identifiers work? |
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Definition
When the device does not provide the Page 83 information, the host generates an mpx.path name, where path represents the path to the device, for example, mpx.vmhba1:C0:T1:L3. This identifier can be used in the same way as the SCSI INQUIRY identifies.
The mpx. identifier is created for local devices on the assumption that their path names are unique. However, this identifier is neither unique nor persistent and could change after every boot. |
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Term
| When are Legacy Identifiers used? |
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Definition
In addition to the SCSI INQUIRY or mpx. identifiers, for each device, ESXi generates an alternative legacy name. The identifier has the following format:
vml.number
The legacy identifier includes a series of digits that are unique to the device and can be derived in part from the Page 83 information, if it is available. For nonlocal devices that do not support Page 83 information, the vml. name is used as the only available unique identifier. |
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Term
| Which identifier is unique across all hosts and persistant? |
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Definition
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Term
| Which identifier could change after re-boot? |
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Definition
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Term
| Which vSphere CLI command can you use to get all device names displayed in the vSphere CLI? |
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Definition
| esxcli --server=server_name storage core device list |
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Term
| What is runtime name? Can you use it as a reliable identifier? |
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Definition
| In the vSphere Client, you can see the device identifier and a runtime name. The runtime name is generated by the host and represents the name of the first path to the device. It is not a reliable identifier for the device, and is not persistent. |
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