FreeBSD 10.3 - nvme regression

[Borja Marcos]

> On 07 Mar 2016, at 15:28, Jim Harris <jim.harris at gmail.com> wrote:
> (Moving to freebsd-stable.  NVMe is not associated with the SCSI stack at all.)

Oops, my apologies. I was assuming that, being storage stuff, -scsi was a good list. 

> Can you please file a bug report on this?

Sure, doing doing some simple tests right now and I’ll file it.


> 
> Also, can you try setting the following loader variable before install?
> 
> hw.nvme.min_cpus_per_ioq=4

It now boots, thanks :)

Note that it’s the first time I use NVMe drives, so bear with me in case I do anything stupid ;)

I have noticed some odd performance problems. I have created a “raidz2” ZFS pool with the 10 drives.

Doing some silly tests with several “Bonnie++” instances, I have noticed that delete commands seem to be
very slow. After running several bonnie++ instances in parallel, when deleting the files, the drivers
are almost stuck for a fairly long time, showing 100% bandwidth usage on “gstat” and indeed being painfully
slow.

Disabling the usage of BIO_DELETE for ZFS (sysctl vfs.zfs.vdev.bio_delete_disable=1) solves this problem, although,
of course, BIO_DELETE is desirable as far as I know. 

I observed the same behavior on 10.2.

This is not a proper report, I know, I will follow up tomorrow. 

Thanks!





Borja.