[Info-vax] VMS and the (lack of the) TRIM facility.

[Stephen Hoffman]

On 2015-06-20 11:18:28 +0000, johnwallace4 at yahoo.co.uk said:

> SANs surely don't see "files", they see blocks?

Various storage controllers can and do see files and objects; 
organizations or units of data above the sector.   Like the 
layer-crossing design of ZFS, host operating systems and storage 
controllers that share and that have knowledge of files and objects can 
be very useful for certain operations of interest to the storage 
controllers, too.  In some cases the controllers have file system 
knowledge and peek directly, and in other cases there are host-based 
shims or probes that the controllers can access within the run-time 
context of the operating system, and the end-state of this will almost 
certainly involve an API that is shared between the storage and the 
host operating systems.

The OpenVMS storage model is comparatively old and limited, so file and 
object storage isn't something that many OpenVMS folks have probably 
encountered.

Here are some of the HP 3PAR product offerings: 
http://h20195.www2.hp.com/v2/GetPDF.aspx/4AA2-3001ENW.pdf



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