From: "Mike Snitzer" <snitzer@gmail.com>
To: linux-lvm@redhat.com
Subject: [linux-lvm] walltime of pvs vs pvdisplay with 256 PVs
Date: Wed, 15 Nov 2006 21:54:54 -0500 [thread overview]
Message-ID: <170fa0d20611151854m4bc49ed6qc696e82f83417e7@mail.gmail.com> (raw)
I have a testbed with 256 PVs. Running 'pvdisplay -c' takes .672 sec.
Running 'pvs' takes 43sec! I've tried this on RHEL4U3
(lvm2-2.02.01-1.3.RHEL4) and RHEL4U4 (lvm2-2.02.06-6.0.RHEL4). lvm2
from U4 is actually slower than U3 on this issue (1m vs 43s).
With RHEL4U3, pvs -vvvvv shows that a single device gets opened 264
times yet pvdisplay -c -vvvvv only opens a single device 8 times.
With RHEL4U4, there are 261 opens for pvs and 5 opens for pvdisplay
-c. Clearly there is something flawed in the pvs algorithm. I can
dig deeper but I wanted to put this info out there in case others
might have some insight.
please advise, thanks.
Mike
reply other threads:[~2006-11-16 2:55 UTC|newest]
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