I/O Distribution - Dell PowerVault MD3000i Tuning Manual

Dell™ PowerVault MD3000 and MD3000i Array Tuning Best Practices
Figure 2: First Generation Firmware - RAID Level. File: stateCaptureData.txt
Virtual Disk Unit 0 Configuration
Volume Type:
User Label:
Block Size:
Large IO:
Segment Size:
Stripe Size:
...
IO Statistics:
requests
blocks
avg blocks
IO pct.
reads
writes
write
algorithms
Figure 3: Second Generation Firmware - RAID Level. File: stateCaptureData.txt
Volume 0 Attributes:
Volume Type:
User Label:
...
BlockSize:
LargeIoSize:
...
Perf. Stats:

4.7.3 I/O Distribution

I/O can be characterized by its distribution and pattern. The two primary factors
in determining the I/O distribution of an application are the randomness of I/O
and the direction of I/O. The randomness of I/O indicates how sequential or
random the data access is, as well as the patterning of this data access. The
direction of the I/O can be simply related to the read and write percentages of
I/O, that is, the direction I/O is taking from the storage device. I/O pattern refers
December 2008 – Revision A01
13+1 RAID 5
MyRAID5_1
512 bytes
4096 blocks
256 blocks
3328 blocks
small small
reads writes
2028332119 147699066
3091968111 2518067526
4
93.21% 6.78%
IOs stripes
2028332119 2034477363
147699066 148449472
Full Partial
1105611 12598366
RAIDVolume
MyRAID10_One
512 bytes
4096 blocks
Requests
Reads 67456452 5943724625
Writes 27283249 1144902648
Large Reads
Large Writes
Total 94739701 7088627273
large
reads writes
0
0
17 0
0.00%
/IO clusters
1.00 2107869128
1.00 157404718
RMW No Parity
32120072
Blocks Avg. Blks
0 0
0 0
large
total
0 2176031185 1289775370
0 1315068341 4019884678
0 0
0.00% 0.00%
/IO
1.03
1.06
RMW2
0 0
IO Percent
88 71.20%
41 28.80%
0 0.00%
0 0.00%
74 100.00%
cache
hits
3
59.27%
FSWT
0
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