Date: Mon, 19 Jun 2017 22:14:11 +0000 From: "Caza, Aaron" <Aaron.Caza@ca.weatherford.com> To: "freebsd-fs@freebsd.org" <freebsd-fs@freebsd.org> Subject: FreeBSD 11.1 Beta 2 ZFS performance degradation on SSDs Message-ID: <a5d5c979ef6e4889b619cfc626b59004@DM2PR58MB013.032d.mgd.msft.net>
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I've been having a problem with FreeBSD ZFS SSD performance inexplicably d=
egrading after < 24 hours uptime as described in a separate e-mail thread.=
In an effort to get down to basics, I've now performed a ZFS-on-Root inst=
all of FreeBSD 11.1 Beta 2 amd64 using the default Auto(ZFS) install using =
the default 4k sector emulation (vfs.zfs.min_auto_ashift=3D12) setting (no =
swap, not encrypted).
Firstly, the vfs.zfs.min_auto_ashift=3D12 is set correctly in the /boot/loa=
der.conf file, but doesn't appear to work because when I log in and do "sys=
tctl -a | grep min_auto_ashift" it's set to 9 and not 12 as expected. I tr=
ied setting it to vfs.zfs.min_auto_ashift=3D"12" in /boot/loader.conf but t=
hat didn't make any difference so I finally just added it to /etc/sysctl.co=
nf where it seems to work. So, something needs to be changed to make this =
functionaly work correctly.
Next, after reboot I was expecting somewhere in the neighborhood of 950MB/s=
from the ZFS mirrored zpool of 2 Samsung 850 Pro 256GB SSDs that I'm using=
as I was previously seeing this before with my previous FreeBSD 11-Stable =
setup which, admittedly, is a different from the way the bsdinstall script =
does it. However, I'm seeing half that on bootup.
Performance result:
Starting 'dd' test of large file...please wait
16000+0 records in
16000+0 records out
16777216000 bytes transferred in 37.407043 secs (448504207 bytes/sec)
Zpool Status:
pool: zroot
state: ONLINE
scan: none requested
config:
NAME STATE READ WRITE CKSUM
zroot ONLINE 0 0 0
mirror-0 ONLINE 0 0 0
ada0p2 ONLINE 0 0 0
ada1p2 ONLINE 0 0 0
/boot/loader.conf:
kern.geom.label.disk_ident.enable=3D"0"
kern.geom.label.gptid.enable=3D"0"
vfs.zfs.min_auto_ashift=3D12
vfs.zfs.arc_min=3D"50M"
vfs.zfs.arc_max=3D"51M"
zfs_load=3D"YES"
/etc/sysctl.conf:
vfs.zfs.min_auto_ashift=3D12
Is this the expected behavior now in FreeBSD 11.1?
--
Aaron
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