[Linux-cluster] gnbd export

Steve Maddison smaddison at competa.com
Wed Aug 20 11:51:21 UTC 2008

Chris Mavin wrote:
> I have a running cluster but the gnbd export on the storage server is
> exporting a logical volume rather then the raw device.
> It all seems to work fine but would exporting the raw device improve
> performance or anything?

If you're asking whether the use of a logical volume as opposed to a raw
device makes any difference in performance, it depends on how the logical
volume was set up. If the LV is spread over several physical devices,
performance can be affected depending on whether the data is striped,
mirrored or appended linearly. If a single device is simply being used as
a "container" for the LV, the additional overhead may ever so slightly
degrade performance (although the difference is usually negligible).

The advantage of using a logical volume is of course that you can easily
manipulate it, for example to add more physical storage space later.


Steve Maddison
Sr. Unix/Linux Engineer
Competa IT B.V.

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