measuring IO asynchronously

Mikolaj Golub trociny at freebsd.org
Mon Oct 10 18:05:58 UTC 2011


On Mon, 10 Oct 2011 16:33:11 +0200 Patrick Proniewski wrote:

 PP> Hello,

 PP> I would like to monitor the storage on various FreeBSD servers,
 PP> especially I/O per seconds. Is there any way to gather statistics
 PP> about I/O via asynchronous request, lets say, for example, using a
 PP> munin plugin?  `iostat -w 1` and `zpool iostat tank 1` are
 PP> interesting, but not useable asynchronously.

I use for this a simple program that I wrote some time ago. It uses devstat(9)
kernel interface and outputs counters, like below

kopusha:~% devstat ada0   
ada0:
        1339552256 bytes read
        858508800 bytes written
        0 bytes freed
        26711 reads
        52207 writes
        0 frees
        32 other
        duration:
                329 15518804455250054608/2^64 sec reads
                116 18223026934881081924/2^64 sec writes
                0 0/2^64 sec frees
        296 15557434685545187896/2^64 sec busy time
        5 18134849003398009609/2^64 sec creation time
        512 block size
        tags sent:
                78950 simple
                0 ordered
                0 head of queue
        supported statistics measurements flags: 0
        device type: 32
        devstat list insert priority: 272

You can find it in ports (sysutils/devstat).

-- 
Mikolaj Golub


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