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To: "Peter Jeremy" <peter@rulingia.com>, "E.S. Rosenberg" <esr@cs.huji.ac.il>, 
 "Andriy Gapon" <avg@freebsd.org>
Cc: freebsd-fs@freebsd.org
Subject: Re: raw filesystem counters
References: <CA+K1OzSda42zBCfT4n0_DScf74TsJyHsxBHaxZwcjkOe3ccmwA@mail.gmail.com>
 <20180212055505.GD3353@server.rulingia.com>
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Date: Mon, 12 Feb 2018 13:50:13 +0100
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From: "Ronald Klop" <ronald-lists@klop.ws>
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On Mon, 12 Feb 2018 10:07:07 +0100, Andriy Gapon <avg@freebsd.org> wrote:

> On 12/02/2018 07:55, Peter Jeremy wrote:
>> On 2018-Feb-11 21:06:12 +0200, "E.S. Rosenberg" <esr@cs.huji.ac.il>  
>> wrote:
>>> Is there any way to access raw disk counters similar to those found on
>>> Linux in:
>>> /sys/class/block/<device>/stat
>>>
>>> Preferably also by accessing such a virtual file and not by using  
>>> iostat /
>>> zpool iostat which are already pre-processing counters and need to be  
>>> run
>>> constantly to get accurate real-time estimates.
>>
>> For the raw disk data, have a look at the statistics functions in
>> libgeom(3).  You can use the source code for gstat(8) to get a better  
>> idea
>> how to drive it.
>
> Or maybe devstat(3).

Or dtrace?


>> I don't know of any published API for vdev-level ZFS statistics and,
>> unfortunately, "zpool iostat" only supports "humanized" output, which  
>> makes
>> it difficult to use them as input to further monitoring.  There are some
>> ARC statistics under sysctl kstat.zfs.misc
>>
>