Gvinum RAID5 performance

freebsd_at_newmillennium.net.au
Date: 10/31/04

  • Next message: Lukas Ertl: "Re: Gvinum RAID5 performance"
    To: <freebsd-current@freebsd.org>
    Date: Mon, 1 Nov 2004 09:55:50 +1100
    
    

    I've just added 4 x Seagate 200GB IDE hard drives to my system, and have
    created a RAID5 setup (279KB stripe size) across all 4 new disks with
    the volume name 'newexport'. Each drive is a single drive with its own
    IDE channel.

    The current gvinum config is below:

    gvinum -> l
    6 drives:
    D drive5 State: up /dev/ad10s1d A: 0/190654 MB
    (0%)
    D drive4 State: up /dev/ad8s1d A: 0/190654 MB
    (0%)
    D drive2 State: up /dev/ad6s1d A: 0/190654 MB
    (0%)
    D drive3 State: up /dev/ad4s1d A: 0/190654 MB
    (0%)
    D drive1 State: up /dev/ad2s1d A: 0/114345 MB
    (0%)
    D drive0 State: up /dev/ad0s1d A: 0/114345 MB
    (0%)

    8 volumes:
    V newexport State: up Plexes: 1 Size: 558
    GB
    V root State: up Plexes: 2 Size: 160
    MB
    V home State: up Plexes: 2 Size: 8192
    MB
    V usr State: up Plexes: 2 Size: 8192
    MB
    V var State: up Plexes: 2 Size: 512
    MB
    V pgsql State: up Plexes: 2 Size: 512
    MB
    V squid State: up Plexes: 1 Size: 2048
    MB
    V export State: up Plexes: 1 Size: 187
    GB

    13 plexes:
    P newexport.p0 R5 State: up Subdisks: 4 Size: 558
    GB
    P root.p0 C State: up Subdisks: 1 Size: 160
    MB
    P root.p1 C State: up Subdisks: 1 Size: 160
    MB
    P home.p0 C State: up Subdisks: 1 Size: 8192
    MB
    P home.p1 C State: up Subdisks: 1 Size: 8192
    MB
    P usr.p0 C State: up Subdisks: 1 Size: 8192
    MB
    P usr.p1 C State: up Subdisks: 1 Size: 8192
    MB
    P var.p0 C State: up Subdisks: 1 Size: 512
    MB
    P var.p1 C State: up Subdisks: 1 Size: 512
    MB
    P pgsql.p0 C State: up Subdisks: 1 Size: 512
    MB
    P pgsql.p1 C State: up Subdisks: 1 Size: 512
    MB
    P squid.p0 S State: up Subdisks: 2 Size: 2048
    MB
    P export.p0 S State: up Subdisks: 2 Size: 187
    GB

    18 subdisks:
    S newexport.p0.s3 State: up D: drive5 Size: 186
    GB
    S newexport.p0.s2 State: up D: drive4 Size: 186
    GB
    S newexport.p0.s1 State: up D: drive3 Size: 186
    GB
    S newexport.p0.s0 State: up D: drive2 Size: 186
    GB
    S root.p0.s0 State: up D: drive0 Size: 160
    MB
    S root.p1.s0 State: up D: drive1 Size: 160
    MB
    S home.p0.s0 State: up D: drive0 Size: 8192
    MB
    S home.p1.s0 State: up D: drive1 Size: 8192
    MB
    S usr.p0.s0 State: up D: drive0 Size: 8192
    MB
    S usr.p1.s0 State: up D: drive1 Size: 8192
    MB
    S var.p0.s0 State: up D: drive0 Size: 512
    MB
    S var.p1.s0 State: up D: drive1 Size: 512
    MB
    S pgsql.p0.s0 State: up D: drive0 Size: 512
    MB
    S pgsql.p1.s0 State: up D: drive1 Size: 512
    MB
    S squid.p0.s0 State: up D: drive0 Size: 1024
    MB
    S squid.p0.s1 State: up D: drive1 Size: 1024
    MB
    S export.p0.s0 State: up D: drive0 Size: 93
    GB
    S export.p0.s1 State: up D: drive1 Size: 93
    GB

    So far so good.

    Now, running a dd from a plex gives me less performance than running a
    dd from one of the subdisks, even though the array is not running in
    degraded mode.

    picard# dd if=/dev/gvinum/sd/newexport.p0.s0 of=/dev/null bs=16M
    count=100
    100+0 records in
    100+0 records out
    1677721600 bytes transferred in 25.873485 secs (64843279 bytes/sec)
    picard# dd if=/dev/gvinum/plex/newexport.p0 of=/dev/null bs=16M
    count=100
    100+0 records in
    100+0 records out
    1677721600 bytes transferred in 28.513923 secs (58838680 bytes/sec)

    Also, something seems to blow up when running a newfs, but I don't get a
    panic. It could be a hardware issue, and I'll try reading/writing from
    the raw drives to verify this later.

    picard# newfs -L export -U /dev/gvinum/newexport
    /dev/gvinum/newexport: 571962.0MB (1171378176 sectors) block size 16384,
    fragment size 2048
            using 3113 cylinder groups of 183.77MB, 11761 blks, 23552
    inodes.
            with soft updates
    super-block backups (for fsck -b #) at:
     160, 376512, 752864, 1129216, 1505568, 1881920, 2258272, 2634624,
    3010976, 3387328, 3763680, 4140032, 4516384, 4892736, 5269088, 5645440,
    6021792, 6398144, 6774496, 7150848, 7527200, 7903552, 8279904,
     8656256, 9032608, 9408960, 9785312, 10161664, 10538016, 10914368,
    11290720, 11667072, 12043424, 12419776, 12796128, 13172480, 13548832,
    13925184, 14301536, 14677888, 15054240, 15430592, 15806944,
     16183296, 16559648, 16936000, 17312352, 17688704, 18065056, 18441408,
    18817760, 19194112, 19570464, 19946816, 20323168, 20699520, 21075872,
    21452224, 21828576, 22204928, 22581280, 22957632, 23333984,
     23710336, 24086688, 24463040, 24839392, 25215744, 25592096, 25968448,
    26344800, 26721152, 27097504, 27473856, 27850208, 28226560, 28602912,
    28979264, 29355616, 29731968, 30108320, 30484672, 30861024,
     31237376, 31613728, 31990080, 32366432, 32742784, 33119136, <machine
    consistently locks up at this point>

    On a final note, I'd like to implement the ability to grow RAID5 plexes
    - any suggestions on where to start?

    -- 
    Alastair D'Silva           mob: 0413 485 733
    Networking Consultant      fax: 0413 181 661
    New Millennium Networking  web: http://www.newmillennium.net.au
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  • Next message: Lukas Ertl: "Re: Gvinum RAID5 performance"

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