On 04/29/2016 05:47 PM, Laurence Oberman wrote:
From: "Bart Van Assche" <[email protected]>
To: "Laurence Oberman" <[email protected]>
Cc: "James Bottomley" <[email protected]>, "linux-scsi" <[email protected]>,
"Mike Snitzer" <[email protected]>, [email protected], "device-mapper development"
<[email protected]>, [email protected]
Sent: Friday, April 29, 2016 8:36:22 PM
Subject: Re: [dm-devel] [Lsf] Notes from the four separate IO track sessions at
LSF/MM
On 04/29/2016 02:47 PM, Laurence Oberman wrote:
Recovery with 21 LUNS is 300s that have in-flights to abort.
[ ... ]
eh_deadline is set to 10 on the 2 qlogic ports, eh_timeout is set
to 10 for all devices. In multipath fast_io_fail_tmo=5
I jam one of the target array ports and discard the commands
effectively black-holing the commands and leave it that way until
we recover and I watch the I/O. The recovery takes around 300s even
with all the tuning and this effectively lands up in Oracle cluster
evictions.
This discussion started as a discussion about the time needed to fail
over from one path to another. How long did it take in your test before
I/O failed over from the jammed port to another port?
>
> Around 300s before the paths were declared hard failed and the
> devices offlined. This is when I/O restarts.
> The remaining paths on the second Qlogic port (that are not jammed)
> will not be used until the error handler activity completes.
>
> Until we get these for example, and device-mapper starts declaring
> paths down we are blocked.
> Apr 29 17:20:51 localhost kernel: sd 1:0:1:0: Device offlined - not
> ready after error recovery
> Apr 29 17:20:51 localhost kernel: sd 1:0:1:13: Device offlined - not
> ready after error recovery
Hello Laurence,
Everyone else on all mailing lists to which this message has been posted
replies below the message. Please follow this convention.
Regarding the fail-over time: the ib_srp driver guarantees that
scsi_done() is invoked from inside its terminate_rport_io() function.
Apparently the lpfc and the qla2xxx drivers behave differently. Please
work with the maintainers of these drivers to reduce fail-over time.
Bart.
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