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Subject: Re: continuous stream of writes?
To: Michael Butler <imb@protected-networks.net>,
 freebsd-current <freebsd-current@freebsd.org>
References: <56D5A59E.8040608@protected-networks.net>
From: Eric van Gyzen <vangyzen@FreeBSD.org>
Message-ID: <56D5AA10.5090703@FreeBSD.org>
Date: Tue, 1 Mar 2016 08:41:20 -0600
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On 03/01/2016 08:22, Michael Butler wrote:
> On an otherwise idle machine, I now see a continuous stream of writes to
> disk. I've only noted this over the last couple of weeks but this will
> not be welcome behaviour on an SSD ..
>
> How do I find the source of these writes?
>
>
> imb@toshi:/home/imb> iostat 10
>        tty            ada0              cd0            pass0             cpu
>  tin  tout  KB/t tps  MB/s   KB/t tps  MB/s   KB/t tps  MB/s  us ni sy in id
>    0   992 58.53 229 13.10   0.00   0  0.00   0.37   0  0.00  13  2  7  1 78
>    0    23 30.82  12  0.36   0.00   0  0.00   0.00   0  0.00   2  0  4  0 94
>    0     8 31.38  12  0.37   0.00   0  0.00   0.00   0  0.00   0  0  4  0 96
>    0     8 31.75  11  0.34   0.00   0  0.00   0.00   0  0.00   3  0  3  0 94
>    0     8 31.82  11  0.35   0.00   0  0.00   0.00   0  0.00   1  0  3  0 96
>    0     8 31.76  12  0.36   0.00   0  0.00   0.00   0  0.00   0  0  3  0 96
>    0     8 31.75  11  0.35   0.00   0  0.00   0.00   0  0.00   1  0  4  0 95
>    0     8 31.55  12  0.38   0.00   0  0.00   0.00   0  0.00   1  0  3  0 96
>

The I/O mode of "top" might be useful:

    top -m io

Eric