SUMMARY: RAID interleave for Solaris Volume Manager

Many thanks to Kevin Buterbaugh for an excellent reply and book rec.

>      The "-i" option to metainit is the amount of data that 
> is going to be written per disk before moving to the next 
> disk in the stripe.  Therefore, in your RAID 0+1 example, 
> an interlace of 16K with give a 80K chunk.  For 
> a 10 disk RAID 5, a 16K interlace gives a 144K chunk.

> What's really important is matching up the interlace given to 
> metainit with the maxcontig parameter passed to the newfs 
> command when creating a UFS filesystem.  The maxcontig should 
> be some integer multiple of the chunk size.  So, for example, 
> with your RAID 0+1 stripe, you'd want a maxcontig of 80 or 160 
> or 240 or ... K.  HTH
> 
> If you don't have it, I'd recommend picking up a copy of "System 
> Performance Tuning" (2nd edition) by Musumeci / Loukides, published 
> by O'Reilly.  It's got a more detailed explanation of what I've 
> tried to summarize above.  HTH...

Along with this I am using the forcedirectio and noatime flags. Performance
has increased about 2.5 times.

 

Thanks again for being a great resource.
-ansh

P.S. I'm sorry if I offended the charter of the list by asking a simple
question. Hichael Morton [mh1272@yahoo.com] seems to have been particularly
irked. Anyway, I think this was an operational question and the
documentation was obscure.




> ==================================
> 
> Kevin Buterbaugh - Systems Engineer
> LifeWay - www.lifeway.com

 
> sunmanagers-bounces@sunmanagers.org wrote on 06/30/2003 12:51:11 AM:
> 
> > Hi managers,
> > 
> > I have a basic question regarding  -i flag for metainit. 
> > What does this interlace size mean in terms of actual disk 
> > writes ?
> > 
> > Suppose I have an application that writes in 64KB chunks. I 
> > want Solaris Volume manager (on solaris 9) to match this: 
> > I am trying to dodge multiple writes per application write 
> > 
> > 1) For a RAID 0+1 volume composed of  5+5 disks -i 16k will 
> > give a __kb chunk ?
> > 2) For a RAID 5 volume of 10 disks how is this stripe size 
> > related to interlace ?
> > 
> > What should I read to grasp this relationship ? Basically I 
> > am trying to extract as much performance from a A5200 as 
> > possible.
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