Can you explain the reason about 'zfs set sync=disabled mdt0'? Are you ready to lose last transaction on that mdt during power failure? What did I miss?<br /><br /><div>14.03.2019, 01:00, "Riccardo Veraldi" <Riccardo.Veraldi@cnaf.infn.it>:</div><blockquote type="cite"><div text="#000000" bgcolor="#FFFFFF">
<div>these are the zfs settings I use on my
MDSes</div>
<div><br />
zfs set mountpoint=none mdt0<br />
zfs set sync=disabled mdt0</div><div><br /></div><div>
zfs set atime=off amdt0<br />
zfs set redundant_metadata=most mdt0<br />
zfs set xattr=sa mdt0<br />
</div>
<div><br />
</div>
<div>if youor MDT partition is on a 4KB
sector disk then you can use ashift=12 when you create the
filesystem but zfs is pretty smart and in my case it recognized it
automatically and used ashift=12 automatically.<br />
</div>
<div><br />
</div>
<div>also here are the zfs kernel modules
parameters i use to ahve better performance. I use it on both MDS
and OSSes</div>
<div><br />
</div>
<div>options zfs zfs_prefetch_disable=1<br />
options zfs zfs_txg_history=120<br />
options zfs metaslab_debug_unload=1<br />
#<br />
options zfs zfs_vdev_scheduler=deadline<br />
options zfs zfs_vdev_async_write_active_min_dirty_percent=20<br />
#<br />
options zfs zfs_vdev_scrub_min_active=48<br />
options zfs zfs_vdev_scrub_max_active=128<br />
#options zfs zfs_vdev_sync_write_min_active=64<br />
#options zfs zfs_vdev_sync_write_max_active=128<br />
#<br />
options zfs zfs_vdev_sync_write_min_active=8<br />
options zfs zfs_vdev_sync_write_max_active=32<br />
options zfs zfs_vdev_sync_read_min_active=8<br />
options zfs zfs_vdev_sync_read_max_active=32<br />
options zfs zfs_vdev_async_read_min_active=8<br />
options zfs zfs_vdev_async_read_max_active=32<br />
options zfs zfs_top_maxinflight=320<br />
options zfs zfs_txg_timeout=30<br />
options zfs zfs_dirty_data_max_percent=40<br />
options zfs zfs_vdev_async_write_min_active=8<br />
options zfs zfs_vdev_async_write_max_active=32<br />
</div>
<div><br />
</div>
<div>some people may disagree with me anyway
after years of trying different options I reached this stable
configuration.</div>
<div><br />
</div>
<div>then there are a bunch of other
important Lustre level optimizations that you can do if you are
looking for performance increase.</div>
<div><br />
</div>
<div>Cheers</div>
<div><br />
</div>
<div>Rick</div>
<div><br />
</div>
<div>On 3/13/19 11:44 AM, Kurt Strosahl
wrote:<br />
</div>
<blockquote type="cite" cite="mid:DM6PR09MB30528E5411A135A210E7350CA74A0@DM6PR09MB3052.namprd09.prod.outlook.com">
<div id="divtagdefaultwrappere76c1a16b30fd17657df2a5b8511e54a" style="font-size:12pt;color:#000000;font-family:Calibri,Helvetica,sans-serif;" dir="ltr">
<p style="margin-top:0;margin-bottom:0;">Good Afternoon,</p>
<p style="margin-top:0;margin-bottom:0;"><br />
</p>
<p style="margin-top:0;margin-bottom:0;"> I'm reviewing the
zfs parameters for a new metadata system and I was looking to
see if anyone had examples (good or bad) of zfs parameters?
I'm assuming that the MDT won't benefit from a recordsize of
1MB, and I've already set the ashift to 12. I'm using an
MDT/MGS made up of a stripe across mirrored ssds.</p>
<p style="margin-top:0;margin-bottom:0;"><br />
</p>
<p style="margin-top:0;margin-bottom:0;">w/r,</p>
<div id="Signaturefafadeda655687fd1989a97897b0937a">
<div id="divtagdefaultwrappere76c1a16b30fd17657df2a5b8511e54a" dir="ltr">
<p style="margin-top:0;margin-bottom:0;"><span id="ms-rterangepaste-startd1de3e12437a77d8224c503a51ceb813"></span><span style="color:rgb(51,51,51);font-family:monospace;font-size:14.16px;">Kurt</span><br />
</p>
</div>
</div>
</div>
<br />
<fieldset></fieldset>
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</blockquote>
<p><br />
</p>
</div><div><p>_______________________________________________<br />lustre-discuss mailing list<br /><a href="http:///touch/compose?to=lustre-discuss@lists.lustre.org">lustre-discuss@lists.lustre.org</a><br /><a href="http://lists.lustre.org/listinfo.cgi/lustre-discuss-lustre.org" target="_blank" rel="noopener noreferrer">http://lists.lustre.org/listinfo.cgi/lustre-discuss-lustre.o…</a><br /></p></div></blockquote><div><br /></div><div><br /></div><div><div xmlns="http://www.w3.org/1999/xhtml" style="color:#000000;font-size:12px;font-style:normal;font-variant:normal;font-weight:normal;line-height:normal;text-align:start;text-transform:none;white-space:normal;font-family:Noteworthy-Light;"><span style="font-family:Noteworthy-Light;">____________________________________</span><br />Sincerely,<br />George Melikov</div></div><div><br /></div>