[gpfsug-discuss] Experiences with thinly-provisioned volumes?

[Jonathan Buzzard]

On 23/12/15 12:47, Oesterlin, Robert wrote:
> I’m talking about the case where the storage device uses
> thin-provisioning internally to allow for better utilization. In this
> particular case the vendor array uses thin-provisioning, and I don’t
> have an option to turn it off.

In which case I would argue that the storage array is unsuitable for use 
with GPFS if having that space reserved for GPFS is a problem for you.

But to answer your question if GPFS does not send TRIM/UNMAP commands to 
block devices this is exactly what you would expect just like any other 
file system that does not do discards. Depending on how "smart" the 
storage array is, it might spot if you write zeros all over and reclaim 
the space.

My understanding of GPFS is that you want relatively dumb storage 
devices that don't do or at least can be turned off fancy stuff like 
thin provisioning, tiering, flash cache's etc. because this just gets in 
the way of GPFS.

JAB.

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