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From:Jeremiah Gowdy Date:May 10 2005 5:06am
Subject:Re: Dual Opteron, linux kernels, 64 bit, mysql 4.1, InnoDB
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Apache doesn't cause CPU overhead waiting for the data from the drives, when 
you do blocking I/O, the kernel removes your thread from the runnable queue, 
making it impossible for you to use any CPU time.

Raid 10 has full disk read / write speed benefits, plus you get 1, 
potentially 2 drives of failure without losing data (2 if it is the right 2 
drives that fail).  I don't see any reason to use Raid 3.

Raid 5 is slow on disk writes, because it has to calculate and write the 
parity, but most controllers don't read the partiy and verify it during 
reads (and if they do, you should be able to turn this feature off), 
therefore read speed on Raid 5 should be just fine, it's write speed that 
should suffer.

----- Original Message ----- 
From: <gunmuse@stripped>
To: "Jeremiah Gowdy" <jgowdy@stripped>; "Dathan Pattishall" 
<dathan@stripped>; "Richard Dale" <richard@stripped>; 
<mysql@stripped>
Sent: Monday, May 09, 2005 6:39 PM
Subject: RE: Dual Opteron, linux kernels, 64 bit, mysql 4.1, InnoDB


> Why not Raid 3 and take advantage of disk write and read performance.
>
> Raid 3 isn't commonly used because it has CPU overhead.  But at the same
> time Apache causes CPU overhead waiting for the data from the drives.
>
> I am buying this exact same server With 32 Gig of ram.
>
> Frankly the slowest thing in my current Raid 5 server is still waiting for
> the disks to read.  That is what prompted me to think bigger processors,
> more ram and faster motherboard to compensate for using a Raid 3 to 
> overcome
> the slowest hardware in my server.
>
> Thanks
> Donny Lairson
> President
> 29 GunMuse Lane
> P.O. box 166
> Lakewood NM 88254
> http://www.gunmuse.com
> 469 228 2183
>
>
> -----Original Message-----
> From: Jeremiah Gowdy [mailto:jgowdy@stripped]
> Sent: Monday, May 09, 2005 6:37 PM
> To: Dathan Pattishall; Richard Dale; mysql@stripped
> Subject: Re: Dual Opteron, linux kernels, 64 bit, mysql 4.1, InnoDB
>
>
> I use Redhat Advanced Server v4 (2.6 kernel) on my four dual opteron
> systems.  I've had no real performance issues with the I/O scheduler, but
> that's because I run 8GB of ram with a huge key cache.  I recommend taking
> the box to 8GB of ram, it's worth it.  Definately use RAID 10.
>
> ----- Original Message -----
> From: "Dathan Pattishall" <dathan@stripped>
> To: "Richard Dale" <richard@stripped>; <mysql@stripped>
> Sent: Monday, May 09, 2005 4:15 PM
> Subject: RE: Dual Opteron, linux kernels, 64 bit, mysql 4.1, InnoDB
>
>
>
>
>> -----Original Message-----
>> From: Richard Dale [mailto:richard@stripped]
>> Sent: Sunday, May 08, 2005 9:37 PM
>> To: mysql@stripped
>> Subject: Dual Opteron, linux kernels, 64 bit, mysql 4.1, InnoDB
>>
>> A new server is about to arrive here and will have have 8x15K
>> RPM spindles, dual Opteron processors and 4GB of RAM, and
>> will have around 100GB of database (primarily stock market
>> prices) - the SCSI controller will also have battery-backed
>> RAM too.  InnoDB will be used exclusively.
>>
>> I've searched the list and seen varying reports of which
>> Linux kernels work best etc.
>>
>> I'd be intersted to know the following:
>> a) Which 64 bit Linux distributions are good for the task?
>
>       Suse 8.1 2.4.21-215-smp #1 SMP Tue Apr 27 16:05:19 UTC 2004
> x86_64 unknown
>
>> b) Which 64 bit Linux distributions are bad for the task?
>
> 2.6 the IO sceduler is still messed up.
>      RedHat AS / Suse 9.x are messed up as well
>
>> c) Any comments on kernels, particularly with regard to 64
>> bit support and schedulers?  Any problems with the latest
>> kernels (2.6.11 & 2.6.12-rcX)?
>
>> d) Any recommendations for RAID volume setup
>
> Use RAID-10 split the disks evenly across each channel
>
>
>> e) Any MySQL optimisations for multiple spindles, onboard
>> caching, stripe sizes, RAID5 vs RAID10.
>
>    Don't use RAID5, use Reiser FS if your using SUSE
>
>> f) Any MySQL reliability settings to take into account the
>> battery-backed RAM on the RAID controller?
>>
>> I'm happy to collate the responses into a summary too.
>>
>> I'm aware of the following discussions which describes a
>> reasonably grunty Dual AMD system with a similar
>> configuration to mine:
>> http://meta.wikimedia.org/wiki/Hardware_ordered_April_2005
>> http://meta.wikimedia.org/wiki/Hardware_order_May_2004
>>
>> Best regards,
>> Richard Dale.
>> Norgate Investor Services
>> - Premium quality Stock, Futures and Foreign Exchange Data for
>>   markets in Australia, Asia, Canada, Europe, UK & USA -
>> www.premiumdata.net
>>
>>
>>
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>>
>>
>
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  • Dual Opteron, linux kernels, 64 bit, mysql 4.1, InnoDBRichard Dale9 May
RE: Dual Opteron, linux kernels, 64 bit, mysql 4.1, InnoDBDathan Pattishall10 May
  • Re: Dual Opteron, linux kernels, 64 bit, mysql 4.1, InnoDBJeremiah Gowdy10 May
    • RE: Dual Opteron, linux kernels, 64 bit, mysql 4.1, InnoDBgunmuse10 May
      • Re: Dual Opteron, linux kernels, 64 bit, mysql 4.1, InnoDBJeremiah Gowdy10 May
Re: Dual Opteron, linux kernels, 64 bit, mysql 4.1, InnoDBPeter J Milanese10 May