[smartmontools-support] Long test heavy on I/O

[Bruce Allen]

This is probably due to a poor SMART implementation in the disk
firmware.  If you complain to Seagate about it, they might issue a
firmware update that fixes the issue.  But don't hold your breath.  The
main focus for most disk manufacturers is data density and read/write
performance.    SMART features and the quality of their implementation
is at the bottom of the list of priorities.



On 04.11.17 10:38, Gandalf Corvotempesta wrote:
> Hi to all
> I've seen, on multiple servers, with multiple disks (all SAS, all
> Seagate 15k) that running a smart long test is resulting in very high
> I/O and will slow down any other disk access.
> 
> Based on what I've read on Net, smart long test should be made
> automatically with low priority by disk itself, but is not our case.
> 
> Every time we run a long test on a disk (member of an hardware RAID),
> any VM reading/writing to that disk will show load arout 80-90 and
> after a while, some crashes.
> 
> "iostat -x" show 100% util for that disk.
> 
> If I stop the long test (smartctl -X) load immediatly goes down to 1-2
> (as it should be) and %util from "iostat" will decrease to about
> 30-40%
> 
> Re-running the long test will make the same.
> 
> Other than this, a long test is expected to finish in about 2 hours
> (based on what smart is saying) but after 8 hours is still running.
> 
> Any idea?
> 
> 
> 
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> 

-- 
--------------------------------------------------------------------
Bruce Allen, Adjunct Professor of Physics
Leonard E. Parker Center for Gravitation, Cosmology and Astrophysics
Physics Department
University of Wisconsin - Milwaukee
3135 N Maryland Ave
Milwaukee, 53211 USA

Tel: +1 414-229-4474
Fax: +1 414-229-5589
ballen at uwm.edu