Date: Tue, 20 Jun 2017 17:29:44 +0000 From: "Caza, Aaron" <Aaron.Caza@ca.weatherford.com> To: "freebsd-fs@freebsd.org" <freebsd-fs@freebsd.org>, Karl Denninger <karl@denninger.net> Subject: RE: FreeBSD 11.1 Beta 2 ZFS performance degradation on SSDs Message-ID: <2d8a525e5355406aa7b8bf6690101008@DM2PR58MB013.032d.mgd.msft.net>
next in thread | raw e-mail | index | archive | help
> -----Original Message----- > From: Karl Denninger [mailto:karl@denninger.net] > Sent: Monday, June 19, 2017 7:28 PM > To: freebsd-fs@freebsd.org > Subject: Re: FreeBSD 11.1 Beta 2 ZFS performance degradation on SSDs > > Just one note below... > > On 6/19/2017 19:57, Caza, Aaron wrote: > > > > Note that file /testdb/test is 16GB, twice the size of ram available in= this system. The /testdb directory is a ZFS file system with recordsize= =3D8k, chosen as ultimately it's intended to host a PostgreSQL database whi= ch uses an 8k page size. > Do not make this assumption blindly. Yes, I know the docs say to set > recordsize=3D8k but this is something you need to benchmark against your > actual working data set. > > MANY Postgres workloads are MUCH faster (2x or more!) if you use a > default page size and lz4 compression -- including one I have in > production and have extensively benchmarked. The difference is NOT small= . >.... > > zroot/ticker compressratio 1.53x - > zroot/ticker mounted yes - > zroot/ticker quota none default > zroot/ticker reservation none default > zroot/ticker recordsize 128K default > zroot/ticker mountpoint /usr/local/pgsql/data-ticker local > zroot/ticker sharenfs off default > zroot/ticker checksum fletcher4 > inherited from zroot > zroot/ticker compression lz4 > inherited from zroot > zroot/ticker atime off > inherited from zroot > > You may also want to consider setting logbias=3Dthroughput. In some case= s > the improvement there can be quite material as well -- depending on the > insert/update traffic to the database in question. > > -- > Karl Denninger > karl@denninger.net <mailto:karl@denninger.net> > /The Market Ticker/ > /[S/MIME encrypted email preferred]/ Thanks for the suggestions Karl. I'll investigate further after I resolve = this performance degradation issue I'm experiencing. I recently read anoth= er FreeBSD+ZFS+PostgreSQL user's Scale15x presentation, PostgreZFS, Sean Ch= ittenden if I recall correctly, who also advised lz4 compression + 16K page= size rather than 8K with PostgreZFS. With regards to my performance woes, I was originally using PostgreSQL in m= y posts to freebsd-hackers@freebsd.org but started using 'dd' to remove it = as a point of contention. In attempting to resolve this issue, I tried usi= ng your patch to PR 187594 (https://bugs.freebsd.org/bugzilla/show_bug.cgi?= id=3D187594). Took a bit of effort to find a revision of FreeBSD 10 Stable= to which your FreeBSD10 patch would both apply and compile cleanly; howeve= r, it didn't resolve the issue I'm experiencing. -- Aaron This message may contain confidential and privileged information. If it has= been sent to you in error, please reply to advise the sender of the error = and then immediately delete it. If you are not the intended recipient, do n= ot read, copy, disclose or otherwise use this message. The sender disclaims= any liability for such unauthorized use. PLEASE NOTE that all incoming e-m= ails sent to Weatherford e-mail accounts will be archived and may be scanne= d by us and/or by external service providers to detect and prevent threats = to our systems, investigate illegal or inappropriate behavior, and/or elimi= nate unsolicited promotional e-mails (spam). This process could result in d= eletion of a legitimate e-mail before it is read by its intended recipient = at our organization. Moreover, based on the scanning results, the full text= of e-mails and attachments may be made available to Weatherford security a= nd other personnel for review and appropriate action. If you have any conce= rns about this process, please contact us at dataprivacy@weatherford.com.
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?2d8a525e5355406aa7b8bf6690101008>