From mboxrd@z Thu Jan 1 00:00:00 1970 From: Brad Campbell Subject: Re: recommended way to add ssd cache to mdraid array Date: Thu, 10 Jan 2013 21:13:38 +0800 Message-ID: <50EEBE82.10501@fnarfbargle.com> References: <201212212357.19292.thomas@fjellstrom.ca> <201212222044.27731.thomas@fjellstrom.ca> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <201212222044.27731.thomas@fjellstrom.ca> Sender: linux-raid-owner@vger.kernel.org To: thomas@fjellstrom.ca Cc: linux-raid List-Id: linux-raid.ids On 23/12/12 11:44, Thomas Fjellstrom wrote: > > moose@mrbig:/mnt/mrbig/data/test$ iozone -a -s 32G -r 8M > random random > bkwd record stride > KB reclen write rewrite read reread read write > read rewrite read fwrite frewrite fread freread > 33554432 8192 212507 210382 630327 630852 372807 161710 > 388319 4922757 617347 210642 217122 717279 716150 > > Is this normal for a 7 disk (2TB seagate barracudas) raid array on a pcie x8 > sas controller? > For comparo using the same command line. This is a running system and has a slight but measurable load on the array, but not enough that it should really impact the numbers. This is 10 x WD 2TB Green drives (sloooow) in RAID-6 on a pair of those cards. Formatted ext4. mpt2sas0: LSISAS2008: FWVersion(15.00.00.00), ChipRevision(0x02), BiosVersion(00.00.00.00) md0 : active raid6 sdl[0] sdr[5] sdo[6] sdp[7] sdn[8] sdk[9] sdm[10] sdq[11] sds[4] sdf[12] 15628106752 blocks super 1.2 level 6, 128k chunk, algorithm 2 [10/10] [UUUUUUUUUU] bitmap: 2/15 pages [8KB], 65536KB chunk random random bkwd record stride KB reclen write rewrite read reread read write read rewrite read fwrite frewrite fread freread 33554432 8192 349745 448840 481170 488821 284313 312892 355422 2288708 440818 397878 469964 478596 496619 Not sure this actually means anything though. Regards, Brad