Bug 1348068 - High i/o latency with random write workload from virtual machine(s)
Summary: High i/o latency with random write workload from virtual machine(s)
Keywords:
Status: CLOSED EOL
Alias: None
Product: GlusterFS
Classification: Community
Component: replicate
Version: 3.7.9
Hardware: x86_64
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Krutika Dhananjay
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks: 1392419
TreeView+ depends on / blocked
 
Reported: 2016-06-20 05:21 UTC by Paul Cuzner
Modified: 2017-03-08 11:03 UTC (History)
3 users (show)

Fixed In Version:
Clone Of:
: 1392419 (view as bug list)
Environment:
Last Closed: 2017-03-08 11:03:38 UTC
Regression: ---
Mount Type: ---
Documentation: ---
CRM:
Verified Versions:
Embargoed:


Attachments (Terms of Use)
iometer config file (7.00 KB, text/plain)
2016-06-20 05:21 UTC, Paul Cuzner
no flags Details
screenshot showing the max latency at 4secs within the iometer run (30.36 KB, image/png)
2016-06-20 05:56 UTC, Paul Cuzner
no flags Details

Description Paul Cuzner 2016-06-20 05:21:02 UTC
Created attachment 1169665 [details]
iometer config file

Description of problem:
When using either a replica 3 or sharded replica 3 volume with virtual machines, profiles that exhibit random writes cause high latencies than can sometimes span several seconds.

This has been observed with both fio and iometer as load generators

Sequential writes do NOT exhibit this affect

Version-Release number of selected component (if applicable):


How reproducible:
Every time the workload is run this profile is observed


Steps to Reproduce:
1. use either an fio workload with random write or an iometer profile (attached)
2. track the latency in the vm with pcp
3. 

Actual results:
High latencies are observed which could impact application response times

Expected results:
Spikes in random write workloads are accepted - may be in the 10's of milliseconds - but latencies that are between 600ms 2s are a problem


Additional info:

Comment 1 Paul Cuzner 2016-06-20 05:56:54 UTC
Created attachment 1169677 [details]
screenshot showing the max latency at 4secs within the iometer run

Added a screenshot showing the max latency observed from the iometer run. This is from a single vm running the workload (as per the icf file attached to the case)

Comment 2 Kaushal 2017-03-08 11:03:38 UTC
This bug is getting closed because GlusteFS-3.7 has reached its end-of-life.

Note: This bug is being closed using a script. No verification has been performed to check if it still exists on newer releases of GlusterFS.
If this bug still exists in newer GlusterFS releases, please reopen this bug against the newer release.


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