Hp VMA-series Memory Arrays Instrukcja Użytkownika Pobierz pdf (Strona 222)

222 HP VMA SAN Gateway User’s Guide AM456-9026A

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 <partition_name> ]

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.

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