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Re: i/o read ahead size for lvm

 
Shawn Miller_2
Frequent Advisor

‎02-22-2002 12:58 PM

‎02-22-2002 12:58 PM

i/o read ahead size for lvm

What is the maximum i/o read ahead size for LVM.
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4 REPLIES 4
S.K. Chan
Honored Contributor

‎02-22-2002 01:33 PM

‎02-22-2002 01:33 PM

Re: i/o read ahead size for lvm

I think it is up to 64 4K pages. I may be wrong.
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Shawn Miller_2
Frequent Advisor

‎02-22-2002 02:03 PM

‎02-22-2002 02:03 PM

Re: i/o read ahead size for lvm

Let me reword the question:

Does LVM have a max I/O size and is this an adjustable parameter?
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S.K. Chan
Honored Contributor

‎02-22-2002 02:11 PM

‎02-22-2002 02:11 PM

Re: i/o read ahead size for lvm

The maximum single IO transfer size is 256kbytes (for LVM). I don't think it's adjustable.
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Stefan Farrelly
Honored Contributor

‎02-25-2002 05:29 AM

‎02-25-2002 05:29 AM

Re: i/o read ahead size for lvm


Its all in the vxtunefs man page. The default for JFS (vxfs) filesystems is 64k, and yes it is adjustable using the parameters;
read_pref_io in conjunction with read_nstream.

You can find more in the online manual at docs.hp.com
Im from Palmerston North, New Zealand, but somehow ended up in London...
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