RE: Re: Anaconda doesn't support raid10

["Ross S. W. Walker" <rwalker@xxxxxxxxxxxxx>]

> -----Original Message-----
> From: centos-bounces@xxxxxxxxxx 
> [mailto:centos-bounces@xxxxxxxxxx] On Behalf Of John R Pierce
> Sent: Friday, May 11, 2007 5:57 PM
> To: CentOS mailing list
> Subject: Re:  Re: Anaconda doesn't support raid10
> 
> 
> > Well the reason not to put /boot on the same spindles as md1 has 
> > already been mentioned a few times.  Basically flexibility.
> > What do you mean LVM doesn't really do striping?  What does 
> globbing 
> > mean?  Does it mean there is no performance difference between 
> > striping LVM and just concatenating 2 raid1's?
> 
> 
> conventional stripesets tend to use a stripe size around 32k or 128k 
> bytes.   LVM tends to use a fairly large PE size, often 32MB. 
>   LVM -is- 
> striping these PE's, if you told it to do that, but its striping with 
> this very large chunk size, which means far fewer individual disk 
> operation will utilize both logical drives.   If you have lots of 
> concurrent disk accesses, this may not matter.

LVM interleaving uses 64K chunk by default and writes these chunks
across the extents on the physical volumes in a round robin fashion.
The chunk size can be changed with the -I option and supports 4K to
1M.

Check out lvmcreate and the -i option.

-Ross

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