[CentOS] Slow RAID Check/high %iowait during check after updgrade from CentOS 6.5 -> CentOS 7.2

Wed May 25 17:25:01 UTC 2016
Kelly Lesperance <klesperance at blackberry.com>

They are:

[root at r1k1 ~] # hdparm -I /dev/sda


ATA device, with non-removable media
	Model Number:       MB4000GCWDC                             
	Serial Number:      S1Z06RW9            
	Firmware Revision:  HPGD    
	Transport:          Serial, SATA Rev 3.0



On 2016-05-25, 1:21 PM, "centos-bounces at centos.org on behalf of m.roth at 5-cent.us" <centos-bounces at centos.org on behalf of m.roth at 5-cent.us> wrote:

>Kelly Lesperance wrote:
>> I’ve posted this on the forums at
>> https://www.centos.org/forums/viewtopic.php?f=47&t=57926&p=244614#p244614
>> - posting to the list in the hopes of getting more eyeballs on it.
>> We have a cluster of 23 HP DL380p Gen8 hosts running Kafka. Basic specs:
>> 2x E5-2650
>> 128 GB RAM
>> 12 x 4 TB 7200 RPM SATA drives connected to an HP H220 HBA
>> Dual port 10 GB NIC
>> The drives are configured as one large RAID-10 volume with mdadm,
>> filesystem is XFS. The OS is not installed on the drive - we PXE boot a
>> CentOS image we've built with minimal packages installed, and do the OS
>> configuration via puppet. Originally, the hosts were running CentOS 6.5,
>> with Kafka 0.8.1, without issue. We recently upgraded to CentOS 7.2 and
>> Kafka 0.9, and that's when the trouble started.
>Really stupid question: are the drives in that the ones that came with the
>      mark, who, a few years ago, found serious issues with green drives in a
>                  server....
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