stat(), st_size and st_allocate

["Bruce Vining" <bvining@xxxxxxxxxx>]

st_allocsize represents the number of bytes associated with the file by the
owning file system (in the case of your QNTC usage, Windows 2000).  This
would include data, headers, reserved growth space, and pretty much
anything else the file system associates with the file.  In the case of
stat() returning 69632 (68K), what does Windows show as being the allocated
size?  Some quick testing here showed Windows returning the same size as
stat() on the iSeries.  Someone also wondered if you perhaps had RAID
protection in effect.  This may (may being a disclaimer here...) be causing
a larger allocation than what you may expect (like maybe (disclaimer again)
64K for data and 4K for header).  This value can be influenced by you (at
least for Root, QOpensys, and user-defined file systems) by way of the
QP0L_ATTR_DISK_STG_OPT attribute of Qp0lSetAttr().

st_blocksize represents the preferred size for an IO operation by the file
system, and is not currently used by iSeries (but is set and returned as
part of the file system implementation).

If the desire is to manage by object size/space, I would vote for using
st_allocate.

I'll see if we can get a little more description on these attributes in the
next publishing of the API.

Bruce