[gpfsug-discuss] GPFS on ZFS! ... ?

Jonathan Buzzard jonathan at buzzard.me.uk
Mon Jun 13 20:05:20 BST 2016


On 13/06/16 18:53, Marc A Kaplan wrote:
> How do you set the size of a ZFS file that is simulating a GPFS disk?
>   How do "tell" GPFS about that?
>
> How efficient is this layering, compared to just giving GPFS direct
> access to the same kind of LUNs that ZFS is using?
>
> Hmmm... to partially answer my question, I do something similar, but
> strictly for testing non-performance critical GPFS functions.
> On any file system one can:
>
>    dd if=/dev/zero of=/fakedisks/d3 count=1 bs=1M seek=3000  # create a
> fake 3GB disk for GPFS
>
> Then use a GPFS nsd configuration record like this:
>
> %nsd: nsd=d3  device=/fakedisks/d3  usage=dataOnly pool=xtra
>   servers=bog-xxx
>
> Which starts out as sparse and the filesystem will dynamically "grow" as
> GPFS writes to it...
>
> But I have no idea how well this will work for a critical "production"
> system...
>

For "testing" purposes I just create a logical volume and map it through 
to my bunch of GPFS KVM instances as a disk. Works a treat and SSD's are 
silly money these days so for testing performance is just fine. There 
was a 960GB SanDisk on offer for 160GBP last month.

JAB.

-- 
Jonathan A. Buzzard                 Email: jonathan (at) buzzard.me.uk
Fife, United Kingdom.



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