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Re: higher agcount on LVM2 thinp volumes

To: Dave Chinner <david@xxxxxxxxxxxxx>
Subject: Re: higher agcount on LVM2 thinp volumes
From: Chris Murphy <lists@xxxxxxxxxxxxxxxxx>
Date: Thu, 29 Aug 2013 21:21:15 -0600
Cc: stan@xxxxxxxxxxxxxxxxx, xfs@xxxxxxxxxxx
Delivered-to: xfs@xxxxxxxxxxx
In-reply-to: <20130830025819.GB23571@dastard>
References: <321D1F95-5603-4571-A445-A267DA5F670F@xxxxxxxxxxxxxxxxx> <521FF8F4.9040009@xxxxxxxxxxxxxxxxx> <DD759368-581C-4C94-BC5E-E6EC3A83FC61@xxxxxxxxxxxxxxxxx> <20130830025819.GB23571@dastard>
On Aug 29, 2013, at 8:58 PM, Dave Chinner <david@xxxxxxxxxxxxx> wrote:
> 
> Check the contents of
> /sys/block/<dev>/queue/{minimum,optimal}_io_size for the single
> device, the standard LV and the thinp device.

physical device:

[root@f19s ~]# cat /sys/block/sda/queue/minimum_io_size 
512
[root@f19s ~]# cat /sys/block/sda/queue/optimal_io_size 
0

conventional LV on that physical device:
     
[root@f19s ~]# cat /sys/block/dm-0/queue/minimum_io_size 
512
[root@f19s ~]# cat /sys/block/dm-0/queue/optimal_io_size 
0


thinp pool and LV:

lrwxrwxrwx. 1 root root       7 Aug 29 20:46 vg1-thinp -> ../dm-3

[root@f19s ~]# cat /sys/block/dm-3/queue/minimum_io_size 
512
[root@f19s ~]# cat /sys/block/dm-3/queue/optimal_io_size 
262144
[root@f19s ~]# 

lrwxrwxrwx. 1 root root       7 Aug 29 20:47 vg1-data -> ../dm-4

[root@f19s ~]# cat /sys/block/dm-4/queue/minimum_io_size 
512
[root@f19s ~]# cat /sys/block/dm-4/queue/optimal_io_size 
262144


Chris Murphy

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