Sandia National Laboratories

TEST4
(Phase 1)

Description:
Each test performed is a file-per-process test where each file is a 2 stripe file (utilizing 2 OST's). In this test both OST's are allocated in order on a single OSS. Each file is written using 2 OST's from the same OSS. Once the maximum number of OST's is reached, OST's will be oversubscribed in the same order as initially allocated. The maximum number of OST's used in this test is set to 8. 

Purpose:
The primary purpose of this test is to test oversubscription of OST's in the ratio of approximately 60:1 which is roughly the ratio of compute nodes to IO targets for Red Storm. By limiting the number of OST's to 8 (on 4 OSS's) we could test very large numbers of clients in a reasonable amount of time.

Performance

AVG PER OST Performance

 

AXES:
Y- MiB/sec aggregate transfer for each data point
X - <clients.stripe> increasing client count from 1-496, Constant stripe count of 2.

Testing Parameters:
TEST CODE:    IOR
VERSION:    2.8.10
API:    POSIX
ACCESS:    file-per-process
MAX OST's:    8
MAX OSS's:    4

Observations:
An initial ramp up appears as noted in previous tests followed by somewhat of a saw tooth pattern after client numbers reach the maximum number of OST's (8).  Probably the most important observation from this test is drop off of read rates as clients sizes grow large.  Note that the write rates appear to generally hold up, although sufficient datapoint's were not collected to be conclusive.

Data in TABLE format

RAW data

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