Bug 666227

Summary: vdsm produces too many iops
Product: Red Hat Enterprise Linux 6 Reporter: Ayal Baron <abaron>
Component: vdsmAssignee: Barak <bazulay>
Status: CLOSED CURRENTRELEASE QA Contact: Daniel Paikov <dpaikov>
Severity: urgent Docs Contact:
Priority: urgent    
Version: 6.0CC: abaron, apevec, danken, dornelas, hateya, iheim, ilvovsky, Rhev-m-bugs, rvaknin, sbombe, vromanov, ykaul
Target Milestone: rc   
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: vdsm-4.9-47.el6 Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: 664882 Environment:
Last Closed: 2011-08-19 15:07:46 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 664882    
Bug Blocks:    

Description Ayal Baron 2010-12-29 18:06:52 UTC 
+++ This bug was initially created as a clone of Bug #664882 +++

Hi,

SPM hosts produce ~ 2000 iops, some times even more, every 2 seconds.

This is probably because the periodic inbox reads are being done as the following:

dd if=[path_to_inbox] iflag=direct bs=512 count=2000, while the total size of it  is only 1M

This situation heavily impacts customers SAN.

Thanks,

Vladik
Comment 3 Rami Vaknin 2011-02-08 14:41:42 UTC 
Fixed.
Tested on RHEL6 with vdsm-4.9-47.el6.x86_64,

Before fix dd wrote 512 byte for 2000 times:

Dummy-4556::DEBUG::2011-02-08 11:08:00,896::storage_mailbox::626::Storage.Misc.excCmd::(_checkForMail) 'dd if=/rhev/data-center/ade9f73e-272a-42bb-8b8c-bb3288e0637e/mastersd/dom_md/inbox iflag=direct bs=512 count=2000' (cwd None)

While after fix dd wrote 1M for 1 time:

Dummy-3241::DEBUG::2011-02-08 16:35:45,982::storage_mailbox::632::Storage.Misc.excCmd::(_checkForMail) 'dd if=/rhev/data-center/ade9f73e-272a-42bb-8b8c-bb3288e0637e/mastersd/dom_md/inbox iflag=direct,fullblock count=1 bs=1024000' (cwd None)

Although it's hard to see the exact iops number using iostat, the tps column shows that the inbox's DM device have low iops average which get lower consistently..