RE: Orion... should we believe what we see?
Date: Thu, 28 Feb 2013 17:37:06 +0000
Message-ID: <9F15274DDC89C24387BE933E68BE3FD30827A04B_at_MISOUT7MSGUSR9D.ITServices.sbc.com>
What sort of disk subsystem are you using? I have seen inconsistent performance on all the major SAN and NFS vendors, usually due to either maintenance or problems (i.e. we had 4 failed drives waiting on replacement for example, so some volumes were degraded). Other times it was due purely to load on the SAN from other servers.
If your SAN or NFS was dedicated to your workload (all the other workload stopped) then your results should be closely repeatable.
-----Original Message-----
From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Tornblad, John
Sent: Sunday, February 24, 2013 7:34 PM
To: oracle-l_at_freelists.org
Subject: Orion... should we believe what we see?
We are seeing wildy varying performance in an Orion run meant to simulate a DW workload (large sequential 1MB reads).
The output below seems to be "red flags" all over:
a) Wildly varying results, even counterintuitive results (more concurrent reads = less throughput) b) Latency on the first test (1 concurrent read at a time) showed 34 IOs at a 1-2 sec latency c) In other tests, smaller reads (128KB) seem to perform better but have only yielded a maximum of ~1300 MB/sec
Trying to employ some "USE" (utilization/saturation/errors) methodology but this is time consuming. There is some skepticism of Orion's reliability in our shop. Problem statement: we believe this frame should be producing closer to 2300 MB/sec bandwidth on large sequential IOs.
Any comments regarding weirdness (or normality?) of these results, steps to take next, observations would be greatly appreciated.
Orion's documentation is a little scant and not many (any?) metalink notes regarding effectively using it. I've listened to Alex Gorbachev talk about Orion a couple of times but need more input on what to do or think when "things don't go right".
-john
$ORACLE_HOME/bin/orion -testname test -run advanced -matrix col -num_small 0 -write 0 -type seq -num_streamIO 1 -cache_size 3072 -verbose -num_disks 180 -size_large 1024 -simulate raid0 -stripe 128
Large/Small, 0
1, 43.50
2, 197.40
3, 37.75
4, 568.16
5, 24.11
6, 25.17
7, 67.05
8, 100.88
9, 63.42
10, 64.42
11, 402.35
12, 364.49
13, 76.10
14, 158.64
15, 252.41
16, 591.30
17, 574.85
18, 330.49
19, 176.74
20, 46.64
21, 118.67
22, 144.45
23, 508.20
24, 177.40
25, 185.84
26, 524.93
27, 127.82
28, 53.91
29, 80.99
30, 92.30
60, 555.11
90, 988.31
120, 1019.90
150, 1117.30
180, 1130.85
210, 1119.28
240, 1132.22
270, 1123.01
300, 1146.14
330, 1119.74
360, 1124.75
Latency Histogram for large IOs _at_ Small=0 and Large=1
Latency: # of IOs (read) # of IOs (write)
0 - 1 us: 0 0
2 - 4 us: 0 0
4 - 8 us: 0 0
8 - 16 us: 0 0
16 - 32 us: 0 0
32 - 64 us: 0 0
64 - 128 us: 0 0
128 - 256 us: 0 0
256 - 512 us: 0 0
512 - 1024 us: 0 0
1024 - 2048 us: 2515 0
2048 - 4096 us: 45 0
4096 - 8192 us: 11 0
8192 - 16384 us: 20 0
16384 - 32768 us: 20 0
32768 - 65536 us: 1 0
65536 - 131072 us: 0 0
131072 - 262144 us: 0 0
262144 - 524288 us: 0 0
524288 - 1048576 us: 2 0
1048576 - 2097152 us: 34 0
2097152 - 4194304 us: 0 0
4194304 - 8388608 us: 0 0
8388608 - 16777216 us: 0 0
16777216 - 33554432 us: 0 0
33554432 - 67108864 us: 0 0
67108864 - 134217728 us: 0 0
134217728 - 268435456 us: 0 0
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Received on Thu Feb 28 2013 - 18:37:06 CET