This document discusses HP 3PAR Express Writes, which is a feature of HP 3PAR OS releases from 3.2.1 onwards that optimizes write performance. It reduces the number of interrupts per write transaction, lowering CPU usage. Telemetry data shows systems with 3.2.1 satisfy around 40% of writes within 0.120ms compared to 10% for previous releases. Reports can show around 50% of writes are now under 0.125ms with 3.2.1. The feature benefits all supported host types and workloads like thin deduplication without requiring any host changes.

1. © Copyright 2014 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.© Copyright 2014 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
Anoverviewof:
HP3PARExpress Writes
Ivan Iannaccone
HP 3PAR Product Management

2. © Copyright 2014 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.2
HP 3PAR
HP 3PAR Express Writes
Backend
• HP 3PAR OS changes to deliver lower CPU
interrupts per I/O transaction.
• This results in higher IOPS and reduced latency for
writes.
• Express Writes does not require any changes on
the initators side.
• All supported HBAs and Hosts will benefit of this
optimization.
Flash or HDD
Hosts
Optimized Writes –
fewer interrupts
Cache
Fibre Channel protocol optimization
Optimized code

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HP 3PAR Express Writes – Telemetry Data
Below we are showing Telemetry data from the 3PAR Install Base that compares the amount of write access below 1ms between 3.1.3
and 3.2.1 systems. The data highlighted in the rectangle shows how systems on 3.2.1 (Express Writes Enabled) are able to satisfy more
write request in around 0.120ms (~40% vs 3.1.3 10%).

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Express Writes – SSMC Report
Prior the 3.2.1 upgrade 90% of writes where committed in 0.250microseconds or more,10% where committed in 0.125 microseconds or less.
After the upgrade to 3.2.1 around 50% of writes are now committed in 0.125 microseconds or less.
3.2.1 upgrade

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Express Writes effect on 7450
0
10
20
30
40
50
60
70
80
90
100
0.062 0.125 0.25 0.5
3.1.2 3.2.1
70% of Write IO occurred in 0.25 millisecond
28% of Write IO occurred in 0.5 millisecond
2% of Write IO occurred in 0.125 milliseconds
0% of Write IO occurs in 0.062 milliseconds
45% of Write IO occurs in 0.125 milliseconds
40% of Write IO occurs in 0.250 milliseconds
10% of Write IO occurs in 0.50 milliseconds
5% of Write IO occurs in 0.062 milliseconds
3.2.1 upgrade

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Express Writes and Thin Deduplication
0.00%
20.00%
40.00%
60.00%
80.00%
100.00%
120.00%
0.062 0.125 0.25 0.5 1
Express Writes on AFA with Thin Deduplication
r w t
And to conclude we can also look at a system that was born on HP 3PAR OS 3.2.1 and running a VDI workload with Thinly Deduplicated Volumes (5:1
dedup), as you can see around 40% of write I/O is completed in 0.125 microseconds or less.

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#3PARExpressWrites
Shareyourresultsontwitter!

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How to create a report:
Look at 2 weeks prior and after the upgrade to 3.2.1 using daily sampling.
CLI
(btsecs date in the below example is the time prior the upgrade and etsecs is the date 2 weeks after.
For example if I upgraded on the 15th of November :
• srhistvlun -rw -timecols 4 5 -pct -daily -btsecs "2014-11-01" -etsecs "2014-11-30“
Import the data in excel, filter for the write column, select the 0.125 and 0.250 columns and create a
chart over time!
SSMC
Go under System Reporter and select the Exported Volumes histogram template, select a time range
of 2 weeks prior and 2 weeks after the upgrade of daily sampling. Select IO time values between
0.125 and 0.250 and writes as IO type.

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Example on how to do a report in SSMC using
Exported Volumes, IO Time template.
Pick a range using daily data, 1 week before
and after the upgrade with chart option defined
on the left.

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Results may vary!
• Every workload is different so it’s possible not all systems will see the same benefits.
• Just keep that in mind and try other ‘buckets’ like 0.250 and 0.500 (instead than 0.125
and 0.250)

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Thankyou