Date: Fri, 12 Jul 2013 22:15:03 +0300 From: Artem Naluzhnyy <artem.naluzhnyy@gmail.com> To: Ivan Voras <ivoras@freebsd.org> Cc: freebsd-database@freebsd.org, freebsd-fs@freebsd.org Subject: Re: RAID10 stripe size and PostgreSQL performance Message-ID: <CAEGTrd%2B9YbSRvZuA_WyAimE13fO-YtZPV37dm2vmv5FDTKAmCg@mail.gmail.com> In-Reply-To: <krp1s0$atb$1@ger.gmane.org> References: <CAEGTrdKZetiwczu=39433KtX3Px7vgsJxzFBB-_AtAgsKoYkdw@mail.gmail.com> <krel4o$q96$1@ger.gmane.org> <CAEGTrdKJ_6zXJBuVZ%2BMdK=MS%2BDdGAaRGpX8N-xXjoRhJ2qdLRQ@mail.gmail.com> <krp1s0$atb$1@ger.gmane.org>
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On Fri, Jul 12, 2013 at 4:55 PM, Ivan Voras <ivoras@freebsd.org> wrote: > I just looked at your RAID configuration at http://pastebin.com/F8uZEZdm > and you have a mirror of stripes (RAID-01) nor a stripe of mirrors > (RAID-10). And apparently, is I parse your configuration correctly, you > have a 1M stripe in the MIRROR part of the RAID, and an unknown stripe > size in the STRIPE part. This is probably a bug in mfiutil output. There is no "RAID 01" option in the controller configuration, and its documentation says (http://goo.gl/6X5pe): "RAID 10, a combination of RAID 0 and RAID 1, consists of striped data across mirrored spans. A RAID 10 drive group is a spanned drive group that creates a striped set from a series of mirrored drives. RAID 10 allows a maximum of eight spans. You must use an even number of configuration Scenarios 1-7 drives in each RAID virtual drive in the span. The RAID 1 virtual drives must have the same stripe size." There is also no options to configure a different stripe size for the mirrors, I can only set it globally for the whole RAID 10 volume. > Anyway, could you please do one more test: > > 1) create a large file with "dd if=/dev/zero of=file bs=1m count=48000" > 2) install /usr/ports/benchmarks/randomio > 3) run "randomio file 8 0.5 1 8192 10 10" > > ... and report the results. See results at the end of http://pastebin.com/F8uZEZdm There is yet another issue that makes (I guess it should) all previous benchmarks kinda inaccurate and irrelevant - looks like the the UFS partitions are not aligned properly: $ gpart show => 63 1167966145 mfid0 MBR (557G) 63 1167957567 1 freebsd [active] (556G) 1167957630 8578 - free - (4.2M) => 0 1167957567 mfid0s1 BSD (556G) 0 4194304 1 freebsd-ufs (2.0G) 4194304 16777216 2 freebsd-swap (8.0G) 20971520 1130217472 5 freebsd-ufs (539G) 1151188992 16768575 4 freebsd-ufs (8G) Will also try to fix the alignment and make some tests. -- Artem Naluzhnyy
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