[H-GEN] Debian and booting off a RAID mirror partition

[Ben Martin]

Hi,
  You don't stipulate which software RAID you are using. For the parity
stuff you might like to tell the filesystem the chunk size you have
chosen so it can stripe its data efficiently. I'd use bonnie++ and
iozone instead of just copying a few files around so that the machine
can be optimized for the workload you want (eg, do smaller files
matter).

Some idea of performance numbers, though my purdee gnuplots have been
removed from the article it would seem:
https://www.linux.com/news/hardware/servers/8222-benchmarking-hardware-raid-vs-linux-kernel-software-raid

Some other numbers to see if you are where you should be:
https://raid.wiki.kernel.org/index.php/Performance

Some NAS reviews are also useful for comparison as they just run Linux
soft raids under the covers and have 4-5 disks on a 1-2ghz ARM chip.

Others will also be wondering, how many disks, what type of RAID?


On Thu, 2012-06-21 at 20:01 +0100, Benjamin Fowler wrote:
> [ Humbug *General* list - semi-serious discussions about Humbug and     ]
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> 
> Hi all,
> 
> 
> I've built a Debian server on an old HP MediaSmart box. I had the idea
> of using software RAID to make things a little more failure-tolerant,
> however, the disk throughput is not quite what I had expected
> initially -- I did some ad-hoc testing of creating and moving large
> amounts of data around on disk.
> 
> 
> I'm after some general advice on approaches to doing disk performance
> troubleshooting on home hardware:
> 
> 
>       * How do I get an idea of what is 'normal' performance for a
>         given hardware configuration?
>       * What are common misconfigurations under Linux, that would
>         cause poor performance? (I realize there's potentially a lot,
>         if you take into account low level configuration, e.g.
>         enabling DMA, LVM, software RAID, the filesystem driver
>         itself, partition alignment (my disks have 4kb blocks, but
>         yes, my partitions are aligned on cylinder boundaries).
>       * And last but not least, how do I systematically go about
>         finding and fixing these kinds of performance issues?
> Thanks in advance for any ideas!
> 
> 
> Ben.
> 
> 
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