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: <[EMAIL PROTECTED]>
To: "Jeremiah Gowdy" <[EMAIL PROTECTED]>; "Dathan Pattishall" <[EMAIL PROTECTED]>; "Richard Dale" <[EMAIL PROTECTED]>; <mysql@lists.mysql.com>
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:[EMAIL PROTECTED] Sent: Monday, May 09, 2005 6:37 PM To: Dathan Pattishall; Richard Dale; mysql@lists.mysql.com 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" <[EMAIL PROTECTED]> To: "Richard Dale" <[EMAIL PROTECTED]>; <mysql@lists.mysql.com> 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:[EMAIL PROTECTED] Sent: Sunday, May 08, 2005 9:37 PM To: mysql@lists.mysql.com 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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