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Noor2122
Enthusiast
Enthusiast

RDM LUN size mismatch

While listing the size of RDM LUNs for a MSCS/WFCS database VM, noticed one LUN's size that i got using a PowerCLI script is different (180GB) than what is listed on vSphere Client devices screen (300GB)....then checked using esxcfg-scsidevs -c |grep naa.id and this shows its size same as vSphere client (300GB)

now checked the associated vm_name-rdmp.vmdk file size and it was same as what i got initially from powercli (180GB)....rvtools is also showing the same.

Note: From inside VM, this is a 300GB RDM Disk

If I understand correctly, in datastore browser RDM pointer file's size (vm_name-rdmp.vmdk) would be listed same as RDM's actual size then why its different here.....Can someone help me here to understand why the same RDM's LUN size is showing differently?

- Noor Mohammad
7 Replies
a_p_
Leadership
Leadership

I assume that the RDM's LUN has been increased at some point in time. Unless the RDM mapping file is recreated after resizing the LUN, its contents won't be updated. Since it's only a mapping file, this may not cause issues in production. However, if you are going to convert the RDM to a virtual disk using e.g. vmkfstools - which also relies on the contents of the RDM's .vmdk descriptor file - you may end up with a truncated virtual disk.

André

Noor2122
Enthusiast
Enthusiast

I was also thinking the same but got confused when didn't find any related mail but yes this makes sense.....so in this kind of scenario how we can list RDM LUN size correctly via PowerCLI as Get-HardDisk would list the size of pointer file only.....

Thanks for your response.

- Noor Mohammad
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a_p_
Leadership
Leadership

I'm afraid you can't, except you recreate the mapping file.

Anyway, if you want (just let me know), I can move this discussion to the PowerCLI community. Maybe someone over there can help.

André

Noor2122
Enthusiast
Enthusiast

Yes please move this discussion to the PowerCLI community as it doesn't make sense to recreate the rdm mapping file just for reporting sake...lets see if can find any way around.

Thank you!

- Noor Mohammad
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a_p_
Leadership
Leadership

Discussion moved from VMware ESXi 5  5 to VMware vSphere™ PowerCLI

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LucD
Leadership
Leadership

Can you check what size is shown in the script I just posted in List VMFS and RAW disks with naa.id and multipath policy


Blog: lucd.info  Twitter: @LucD22  Co-author PowerCLI Reference

Noor2122
Enthusiast
Enthusiast

Thanks LucD, I will check with this script and update here.

- Noor Mohammad
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