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From:Michael Widenius Date:January 12 2000 9:26pm
Subject:Re: More details of the --with-raid compilation option?
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>>>>> "Tim" == Tim Bunce <Tim.Bunce@stripped> writes:

Tim> On Wed, Jan 12, 2000 at 12:55:02PM +0200, Tonu Samuel wrote:
>> 
>> Only striping is implemented yet and there is no concrete plans for
>> future. At moment we hadprimary goal to break 2GB file limit and
>> secondary goal to get more speed. More speed can be achieved if these
>> directories with numbers are symlinked or mounted to different physical
>> disks. This should increase speed in heavy IO conditions.

Tim> Are you relying on the operating system + separate disk drives etc to
Tim> achieve that or will there be separate threads handling the I/O for each?

>> RAID_CHUNKS means that we have 4 directories

Tim> Using the word CHUNKS for that seems wrong, at least for the current
Tim> behaviour. Those aren't chunks, their things that hold many chunks.

>> and RAID_CHUNKSIZE means data is striped in chunks of 16kbytes.

Tim> Having RAID_CHUNKSIZE be specified in 1Kbyte units would probably make
Tim> life easier for people: RAID_CHUNKSIZE=16 (or RAID_CHUNKSIZE=16K).

Good point; We will change that.

Tim> Adding a RAID_FIRSTCHUNK=N (or RAID_OFFSET=N, or RAID_FIRST=N) would be
Tim> a simple way to allow greater control over spreading the I/O.
Tim> Currently there's no way of adding a table that won't add I/O to low
Tim> numbered 'chunks'. For example, I might want to have one table in ./00/
Tim> and ./01/ and another table in ./02/ and ./03/.

This is a bit harder to do as one in this case has to change the MyISAM
interface once again, but it shouldn't be impossible to do.

Tim> Also, what are the implications for crash recovery?

This is done on the MyISAM level so myisamchk will work on the hunks
as if  they would one file.  In other words;  Normally it should work
just fine :)

Regards,
Monty
Thread
More details of the --with-raid compilation option?Tim CHURCHES12 Jan
  • Re: More details of the --with-raid compilation option?Tonu Samuel12 Jan
    • Re: More details of the --with-raid compilation option?Tim Bunce12 Jan
      • Re: More details of the --with-raid compilation option?Michael Widenius13 Jan
        • Re: More details of the --with-raid compilation option?Tim Bunce11 Apr
          • Re: More details of the --with-raid compilation option?Michael Widenius12 Apr
  • Re: More details of the --with-raid compilation option?Jan Dvorak12 Jan
  • Re: More details of the --with-raid compilation option?Tonu Samuel13 Jan
  • Re: More details of the --with-raid compilation option?Tonu Samuel13 Jan
    • Re: More details of the --with-raid compilation option?Tim Bunce13 Jan
      • Re: More details of the --with-raid compilation option?Christopher E. Brown13 Jan
        • Re: More details of the --with-raid compilation option?Tonu Samuel13 Jan
          • Re: More details of the --with-raid compilation option?Christopher E. Brown13 Jan
            • Re: More details of the --with-raid compilation option?Benjamin Pflugmann13 Jan
              • Re: More details of the --with-raid compilation option?Christopher E. Brown14 Jan
                • Re: More details of the --with-raid compilation option?Benjamin Pflugmann14 Jan
              • Re: More details of the --with-raid compilation option?Tonu Samuel14 Jan
          • Re: More details of the --with-raid compilation option?Tonu Samuel13 Jan
    • Re: More details of the --with-raid compilation option?Christopher E. Brown13 Jan
  • Re: More details of the --with-raid compilation option?Scott Hess13 Jan
  • Re: More details of the --with-raid compilation option?Tonu Samuel13 Jan
  • Re: More details of the --with-raid compilation option?Tonu Samuel11 Apr
    • Re: More details of the --with-raid compilation option?Tim Bunce12 Apr
Re: More details of the --with-raid compilation option?Andy12 Jan
  • Re: More details of the --with-raid compilation option?Sasha Pachev12 Jan
  • Re: More details of the --with-raid compilation option?Sami Ahlroos13 Jan
  • Re: More details of the --with-raid compilation option?Tonu Samuel13 Jan
Re: More details of the --with-raid compilation option?Steven Roussey21 Jan