HP VMA-series Memory Arrays - Manual (Page 225)

AM456-9007B Rev 02 HP VMA SAN Gateway Installation and User Guide 225
vring
The vring utility debugs the internal HP VMA Array I/O request ring at a low
level, and checks for unaligned flash device access.
Look for the transfer sizes under the column labeled SIZE . If most of the lines
show 4096 , full 4kB accesses are being done to the HP VMA Array hardware,
which is optimal. In an unaligned access case, you will see lines alternate between
512 and 3584 for transfer size, since two read-modify-write operations occur for
each 4kB of data.
Syntax
vring [ -p ]
Completed write I/O's Displays the total I/O write requests to a HP
VMA Array. This is not the individual DMA
descriptors completed, but for each of the user
requested I/Os.
Unaligned host buf
writes Displays the total I/O write requests to a HP
VMA Array, but only incremented when an
unaligned host address required special buffer
byte copying to service the DMA request.
Flash partial page
writes Increments when a DMA descriptor for write
is less than a flash page (4kB) in size, which
leads to a hardware read-modify-write
operation.