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

[Gandalf Corvotempesta]

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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