Magma PCIe Expansion System EB2 用户手册

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页码 74
M A G M A  
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Iometer® is a software-based I/O exerciser capable to test and 
characterize stand-alone as well as clustered storage systems. 
Developed originally by Intel as a proprietary tool, it eventually became 
part of the Open Source Development Lab (OSDL) from which point it 
has undergone several revisions and updates. 
Going back to the Fibre channel host controller cards, one of the 
features that the ATTO FC-44ES supports is the creation of multiple, 
small virtual drives that can be striped by the OS for faster access. What 
that translates to is the ability of two cards to communicate amongst 
themselves at the fastest possible rate, unaffected by delays otherwise 
encountered by moving parts in an actual disk drive.       
By using this method 
combined with the 
Iometer® application, 
one can benchmark 
the communication 
channel and verify that 
the PCIe express link is 
utilized to its fullest 
potential.  
 
 
In the example below, a single ATTO FC-44ES card was installed into 
one of the 4 PCIe expansion slots provided by the EB2 chassis. It was 
then connected via fiber optic cables to a second FC-44ES card (set to 
simulate a fibre disk array, by using a striped set of small virtual drives ). 
Three tests were performed using Iometer. In the first, an equal amount 
of read and write threads were exercised between the two cards. The 
following two tests focused on either all-read or all-write threads. The 
test results are shown in the table below:  
I/O Test type 
Throughput [MByte/sec] 
1003.3 
50% Reads; 50% Writes 
696.1 
100% Reads 
100% Writes 
677.7 
  The results show an aggregate throughput exceeding 1GByte in the 
case where reads and writes are evenly split 50-50 and a slower, more 
realistic rate when only a single type of threads was exercised.