[CentOS] slow performance on company production server I need help

Wed Apr 22 16:15:26 UTC 2020
Christopher Wensink <cwensink at five-star-plastics.com>

Smartctl tests have passed: 

[root at daisy dev]# smartctl -H -d 3ware,0 /dev/twa0
smartctl 5.43 2016-09-28 r4347 [x86_64-linux-2.6.32-042stab142.1] (local
Copyright (C) 2002-12 by Bruce Allen, http://smartmontools.sourceforge.net

SMART overall-health self-assessment test result: PASSED

The problem may have been the USB disk the whole time, and not one of
the internal disks, it's surprising that the performance of the entire
system would suffer that much from a faulting external USB drive.

To monitor the system and ensure that was the root cause, other than
hdparm, what other suggested performance tests should I run to monitor
the performance of the system as a whole?  What is everyone's top rated
performance monitoring commands / apps that can be dumped into cron jobs
or logwatch, etc?


On 4/22/2020 11:00 AM, Gordon Messmer wrote:
> On 4/22/20 8:53 AM, Christopher Wensink wrote:
>> I had an 8 TB External USB disk plugged into the system, that I had been
>> using for additional space for backups, I was under the impression that
>> sda, sdb, sdc, and sdd were the four disks on the raid controller card,
> Not exactly.  If you have a RAID5 array, then you have one volume
> spread across the physical disks.  You can then divide that into
> smaller virtual disks, each of which is still spread across disks. 
> The OS doesn't see the four component disks, directly.
>> but after unplugging the usb drive when running hdparm I am getting
>> this:
>> [root at daisy dev]# hdparm -tT /dev/sdb
>> /dev/sdb:
>> read() hit EOF - device too small
> sdb was the disk that appeared in the kernel errors, so I'd imagine
> that you've fixed the problem by removing the USB drive enclosure.
>> I'm still trying to find the exact smartctl command syntax to make it
>> work.
> https://www.cyberciti.biz/faq/unix-linux-freebsd-3w-9xxx-smartctl-check-hard-disk-command/
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