High IO latency - low FSYNCS rate

TechSean

New Member
Jul 26, 2017
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The usual issue with ext4 has cropped up in my instance of PVE 5x

Using 4x 7200 RPM drives in Hardware (Perc H700) Raid 5, what kind of FYSYNC rate should I be expecting?

I set the barrier=0 in the fstab, and still I'm seeing idle FSYNC of around 100.
 
Fsync should be 3000+

Raid5 and virtualsation ist not a good idea. Less performance. But fsync 100... look likes some HW issue.
 
Yes, the H700 has a new battery connected :(

Any cookie crumbs that can give me an idea what I'm doing wrong?
 
probably writeback disabled

get megacli from:
http://hwraid.le-vert.net/wiki/DebianPackages

get info with:
megacli -LDInfo -LAll -aAll
and look for Current Cache Policy

to enable writeback on the fly with:
megacli -LDSetProp WB -LALL -aALL -NoLog

Installed megacli and ran the command, Current Cache Policy shows as: WriteThrough, ReadAdaptive, Direct, No Write Cache if Bad BBU

Tried to enable writeback, but received an message stating "Battery capacity is below the threshold value" How can I check to verify that the battery connected to the H700 has enough capacity?
 
full bbu info:
megacli -AdpBbuCmd -aAll -NoLog

to force writeback:
megacli -LDSetProp -ForcedWB -Immediate -Lall -aAll
 
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Reactions: chrone
nice. Thank you for the info.

Looks like the Battery isn't being charged. Jesus, these C2100's servers are a nightmare.

BBU status for Adapter: 0

BatteryType: BBU
Battery State: Unknown
Battery backup charge time : 0 hours

BBU Capacity Info for Adapter: 0

Relative State of Charge: 20 %
Absolute State of charge: 20 %
Remaining Capacity: 382 mAh
Full Charge Capacity: 1900 mAh
Run time to empty: Battery is not being charged.
Average time to empty: Battery is not being charged.
Estimated Time to full recharge: Battery is not being charged.
Cycle Count: 0
Max Error = 100 %
Remaining Capacity Alarm = 190 mAh
Remining Time Alarm = 10 Min

BBU Design Info for Adapter: 0

Date of Manufacture: 08/16, 2016
Design Capacity: 1900 mAh
Design Voltage: 3700 mV
Specification Info: 8000
Serial Number: 2632
Pack Stat Configuration: 0xe4ac
Manufacture Name: SMP-PA
Firmware Version :
Device Name: X848372
Device Chemistry: LION
Battery FRU: N/A
Transparent Learn = 0
App Data = 0

BBU Properties for Adapter: 0

Auto Learn Period: 90 Days
Next Learn time: Tue Oct 3 13:37:37 2017
Learn Delay Interval:0 Hours
Auto-Learn Mode: Enabled

Exit Code: 0x00

-------------------
 
I would power off server and reconnect battery again - if this not help maybe battery is bad.
last idea - you can try to force learn cycle:
megacli -AdpBbuCmd -BbuLearn -aALL -NoLog
 
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Once I have another node up, I'll be taking this one down and replacing the battery and cable.
 

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