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Thread: I need help in choosing the right Raid Configuration.

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  1. #1
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    Lightbulb I need help in choosing the right Raid Configuration.

    Hay Guys,

    I own a file hosting service and i am kind of not sure what to do with Raid.
    My server Configuration is as follow:

    HP DL180
    Dual Xeon E5620
    24 GB ECC DDR3 RAM
    12 X 2 TB 7.2 Enterprise Drives
    10Gbps Port Speed

    No i have Raid Configured to RAID5, and it is a disaster.
    I am serving about 30,000 Downloads per day from this server, about 15TB per day.

    My current read speed is as follow:

    Code:
    :~# sudo hdparm -t /dev/sda
    
    /dev/sda:
     Timing buffered disk reads: 232 MB in  3.18 seconds =  73.01 MB/sec
    I don't know what Raid Configuration should i go with, keep in mind that i need as much space as i can.

    Thanks in advance.

  2. #2
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    we also have a DL180 server, just a bit less hdd
    something is not right with your raid config or drivers because we also use RAID5 and we have a much more faster read/write
    RAID speed is mostly depend on the controller, if you have a cheap hardware card it may be slower than the software RAID.
    as i see you have many disk in the array, you should leave one disc for the spare drive at least.

    and one more thing, if you use a hardware card it will be resync your array while you can already use the system, but in the meantime the disc r/w speed is much more slower. once the resync will be finish your array speed will raising.
    12X2 TB disc will be resync for a while

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    I have a HP P410 Raid Card, what do you think?

  4. #4
    phoenix is offline Zimbra Consultant & Moderator
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    Quote Originally Posted by micromaster View Post
    I have a HP P410 Raid Card, what do you think?
    You should not be using RAID5 with a large (I'm assuming that's what you have) or a system with more than 100 users: Performance Tuning Guidelines for Large Deployments - Zimbra :: Wiki - read that article for details (and search the forums for some further advice).
    Regards


    Bill


    Acompli: A new adventure for Co-Founder KevinH.

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    RAID5 can easily handle a massive IO workload. Im using RAID5 all of our servers, with vmware and many many virtual machines, including zimbra, and never had any IO problem.

    micromaster: you have the latest HP firmware upgrade?
    HP released a new firmware DVD in october, i strongly suggest that upgrade your firmware and install the HP drivers bulk pack to your system.

    i just tested our server speed (DL180) last night, 10x600GB SAS hdd in two RAID5 array
    read: 300-400MB/sec
    write: 200-250MB/sec

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    Hi !

    Quote Originally Posted by vadonka View Post
    i just tested our server speed (DL180) last night, 10x600GB SAS hdd in two RAID5 array
    read: 300-400MB/sec
    write: 200-250MB/sec
    1. How did you test it by the way ? With Hdparm ? Bonnie++? iozone?
    2. What Filesystem do you use ?
    3. Do you use LVM ?

    And I haven't quite understood if the original question is related to Zimbra server or some kind of File server :}.

    N.

  7. #7
    phoenix is offline Zimbra Consultant & Moderator
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    Quote Originally Posted by vadonka View Post
    RAID5 can easily handle a massive IO workload.
    Nobody said it couldn't but it doesn't offer the best performance and it certainly does not offer the best security of your data - your data, your servers, your choice.
    Regards


    Bill


    Acompli: A new adventure for Co-Founder KevinH.

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    Quote Originally Posted by vadonka View Post
    1. hdparm -Tt /dev/sda
    2. in esxi 5: VMFS-5, in ubuntu: ext4
    3. no
    Your reads seems to be ok, but writes over 200 MB/s ?? This seams questionable, off course it depends on the block size you use. And you do not get the "write" speed using the command:

    hdparm -Tt /dev/sda

    As it shows only read data. At least I thought so.. In my case with a similar server I could double my writes after changing From raid5 to raid 10 using four SAS disks 10k rpm. This doubling is from 50 to 100 MB/s (write). As for read the numbers are similar.

    And for the initial Question: Maybe you are testing your server under high load ??? This could be the case I guess .. and use proper testing software as Bonnie++ or iozone. When your server is not under high load.

    Quote Originally Posted by micromaster View Post
    I am serving about 30,000 Downloads per day from this server, about 15TB per day.
    And the numbers does not add up :> ... 15TB is 15000000 MB so you need read: 15000000÷3600÷24 = 173.611111111 MB/s. So if you serve such traffic then your tests are showing incorrect results. You should google for perf tests with 7.2 disks and raid 5...

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    sorry, you're right, im using the 'dd' command for the write test

    200MB/sec write speed can achieve with a fast SAS 7200rpm hdd and good hw controller. this speed is internal write speed not over the network.

    i can write to my samba server with 120-150MB/sec over the gigabit network.

    Code:
    root@zimbra:/opt/zimbra/conf# dd if=/dev/zero of=/tmp/test.img bs=102400 count=1000
    1000+0 beolvasott rekord
    1000+0 kiírt rekord
    102400000 bájt (102 MB) másolva, 0,519662 mp, 197 MB/s

  10. #10
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    Hi!

    One more thing to note: to get proper results with the write tests you should write a file at least 2xYour_RAM_size. At least this is what bonnie or iozone does. Otherwise you'll get incorrect results, as probably the ones posted above. In your case it's a little bit harder to do if you have 64 Gigs of ram. I have only 7.

    And if you are testing this on Thin_provisioned/lazy_zeroed disks on ESXi, then the result will vary greatly for the first time and second time writing the same block. As you can't easy tell when it's writing the block for the first or for the second time it's hard to get the correct results on Thin provisioned disks.

    Code:
    root@mail:/opt/test# time sh -c "dd if=/dev/zero of=/opt/test/ddfile1 bs=8k count=17500 && sync"
    17500+0 records in
    17500+0 records out
    143360000 bytes (143 MB) copied, 0.175012 s, 819 MB/s
    
    real    0m1.903s
    user    0m0.000s
    sys     0m0.244s
    
    root@mail:/opt/test# time sh -c "dd if=/dev/zero of=/opt/test/ddfile2 bs=8k count=175000 && sync"
    175000+0 records in
    175000+0 records out
    1433600000 bytes (1.4 GB) copied, 2.50452 s, 572 MB/s
    
    real    0m34.472s
    user    0m0.084s
    sys     0m2.540s
    
    root@mail:/opt/test# time sh -c "dd if=/dev/zero of=/opt/test/ddfile3 bs=8k count=1750000 && sync"
    1750000+0 records in
    1750000+0 records out
    14336000000 bytes (14 GB) copied, 146.679 s, 97.7 MB/s
    
    real    2m28.665s
    user    0m0.580s
    sys     0m42.463s
    Last edited by nooto; 10-11-2012 at 06:20 AM. Reason: Mistakes :}

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