Date: Mon, 8 Jun 2009 12:11:17 -0700 From: Freddie Cash <fjwcash@gmail.com> To: freebsd-hackers@freebsd.org Subject: Re: Request for opinions - gvinum or ccd? Message-ID: <b269bc570906081211o475d8b16r34fd64388b069a19@mail.gmail.com> In-Reply-To: <alpine.BSF.2.00.0906070858210.97807@wojtek.tensor.gdynia.pl> References: <20090530175239.GA25604@logik.internal.network> <20090530144354.2255f722@bhuda.mired.org> <20090530191840.GA68514@logik.internal.network> <20090530162744.5d77e9d1@bhuda.mired.org> <A5BB2D2B836A4438B1B7BD8420FCC6A3@uk.tiscali.intl> <h0ehhv$sic$1@ger.gmane.org> <b269bc570906061316g37290b5q910da0d3ec266c98@mail.gmail.com> <alpine.BSF.2.00.0906070858210.97807@wojtek.tensor.gdynia.pl>
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On Sun, Jun 7, 2009 at 12:01 AM, Wojciech Puchar< wojtek@wojtek.tensor.gdynia.pl> wrote: >>> (very roughly, in the non-sequential access case) expected to deliver >>> performance of four drives in a RAID0 array? >> >> According to all the Sun documentation, the I/O throughput of a raidz >> configuration is equal to that of a single drive. > > exactly what i say. it's like RAID3. Not RAID5 which have close to n times > single drive throughput on read and rougly n/4 on writes. > >> We remade the pool using 3x 8-drive raidz2 vdevs, and performance has >> been great (400 MBytes/s write, almost 3 GBytes/s sequential read, 800 > > why write performance is so slow? in Sun theory it should have the same > speed as reads. I would say that it should be even better a bit - filesystem > get data first in cache and can plan ahead. > >> MBytes/s random read). > > random read on how big chunks? > > Are you sure you get 3GB/s on read? it would mean each drive must be able to > do 140MB/s > > What disks do you use? 12x 500 GB Seagate EL2 SATA drives, part of their enterprise near-line storage line. 12x 500 GB WD SATA drives, generic off-the-shelf drives I re-ran the iozone tests, letting them run to completion, and here are the results: The iozone command: iozone -M -e -+u -T -t <threads> -r 128k -s 40960 -i 0 -i 1 -i 2 -i 8 -+p 70 -C I ran the command using 32, 64, 128, and 256 for <threads> Write speeds range from 236 MBytes/sec to 582 MBytes/sec for sequential; and from 242 MBytes/sec to 550 MBytes/sec for random. Read speeds range from 3.3 GBytes/sec to 5.5 GBytes/sec for sequential; and from 1.8 GBytes/sec to 5.5 GBytes/sec for random. All the gory details are below. 32-threads: Children see ... 32 initial writers = 582468.13 KB/sec 32-threads: Parent sees ... 32 initial writers = 108808.46 KB/sec 64-threads: Children see ... 64 initial writers = 236144.47 KB/sec 64-threads: Parent sees ... 64 initial writers = 86942.94 KB/sec 128-threads: Children see ... 128 initial writers = 284706.68 KB/sec 128-threads: Parent sees ... 128 initial writers = 10850.40 KB/sec 256-threads: Children see ... 256 initial writers = 258260.59 KB/sec 256-threads: Parent sees ... 256 initial writers = 9882.16 KB/sec 32-threads: Children see ... 32 rewriters = 545347.52 KB/sec 32-threads: Parent sees ... 32 rewriters = 339308.08 KB/sec 64-threads: Children see ... 64 rewriters = 419838.51 KB/sec 64-threads: Parent sees ... 64 rewriters = 335620.45 KB/sec 128-threads: Children see ... 128 rewriters = 350668.51 KB/sec 128-threads: Parent sees ... 128 rewriters = 319452.97 KB/sec 256-threads: Children see ... 256 rewriters = 317751.52 KB/sec 256-threads: Parent sees ... 256 rewriters = 295579.66 KB/sec 32-threads: Children see ... 32 random writers = 379256.37 KB/sec 32-threads: Parent sees ... 32 random writers = 95298.44 KB/sec 64-threads: Children see ... 64 random writers = 551767.68 KB/sec 64-threads: Parent sees ... 64 random writers = 113397.95 KB/sec 128-threads: Children see ... 128 random writers = 241980.60 KB/sec 128-threads: Parent sees ... 128 random writers = 74584.01 KB/sec 256-threads: Children see ... 256 random writers = 398427.84 KB/sec 256-threads: Parent sees ... 256 random writers = 20219.56 KB/sec 32-threads: Children see ... 32 readers = 5023742.86 KB/sec 32-threads: Parent sees ... 32 readers = 4661309.72 KB/sec 64-threads: Children see ... 64 readers = 5516460.71 KB/sec 64-threads: Parent sees ... 64 readers = 3949337.61 KB/sec 128-threads: Children see ... 128 readers = 4748635.74 KB/sec 128-threads: Parent sees ... 128 readers = 3208982.03 KB/sec 256-threads: Children see ... 256 readers = 4358453.38 KB/sec 256-threads: Parent sees ... 256 readers = 2741593.08 KB/sec 32-threads: Children see ... 32 re-readers = 5502926.62 KB/sec 32-threads: Parent sees ... 32 re-readers = 4650327.75 KB/sec 64-threads: Children see ... 64 re-readers = 5509400.02 KB/sec 64-threads: Parent sees ... 64 re-readers = 4526444.40 KB/sec 128-threads: Children see ... 128 re-readers = 4072363.55 KB/sec 128-threads: Parent sees ... 128 re-readers = 2840317.47 KB/sec 256-threads: Children see ... 256 re-readers = 3329375.95 KB/sec 256-threads: Parent sees ... 256 re-readers = 2183894.33 KB/sec 32-threads: Children see ... 32 random readers = 5555090.45 KB/sec 32-threads: Parent sees ... 32 random readers = 4602383.62 KB/sec 64-threads: Children see ... 64 random readers = 4402270.77 KB/sec 64-threads: Parent sees ... 64 random readers = 2059081.52 KB/sec 128-threads: Children see ... 128 random readers = 3070466.93 KB/sec 128-threads: Parent sees ... 128 random readers = 525076.11 KB/sec 256-threads: Children see ... 256 random readers = 1888676.12 KB/sec 256-threads: Parent sees ... 256 random readers = 293304.53 KB/sec 32-threads: Children see ... 32 mixed workload = 3130000.18 KB/sec 32-threads: Parent sees ... 32 mixed workload = 123281.78 KB/sec 64-threads: Children see ... 64 mixed workload = 1587053.33 KB/sec 64-threads: Parent sees ... 64 mixed workload = 294586.82 KB/sec 128-threads: Children see ... 128 mixed workload = 807349.95 KB/sec 128-threads: Parent sees ... 128 mixed workload = 98998.77 KB/sec 256-threads: Children see ... 256 mixed workload = 393469.55 KB/sec 256-threads: Parent sees ... 256 mixed workload = 112394.90 KB/sec -- Freddie Cash fjwcash@gmail.com
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