Maximum Number of USB Mass Storage Devices

Patrick Collins

unread,

Feb 18, 2010, 1:26:45 AM2/18/10

to freebsd-...@freebsd.org

I have a requirement to connect a large number of USB bus powered external
hard disks to a FreeBSD 8.0 system. I am talking about hundreds of them. I
am aware of the power and bus limitations and intend to use power hubs and
multiple server USB ports to overcome this issue. My question is this:

Does FreeBSD 8.0-RELEASE have an operating system limitation on the number
of USB storage devices I can connect and mount.

Thanks.

Patrick Collins

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Feb 19, 2010, 2:10:03 AM2/19/10

to David King, freebsd-...@freebsd.org

Thanks David. My question was specific to FreeBSD's limitations rather than
USB limitiations.

On 19/02/2010, David King <dk...@ketralnis.com> wrote:
>
> > I have a requirement to connect a large number of USB bus powered
> external
> > hard disks to a FreeBSD 8.0 system. I am talking about hundreds of them.
>

> The USB spec itself limits to 127 devices per bus, including hubs (and
> including the internal hub-like device on many busses). <
> http://en.wikipedia.org/wiki/Universal_Serial_Bus#Overview>

>
> > I am aware of the power and bus limitations and intend to use power hubs
> and
> > multiple server USB ports to overcome this issue. My question is this:
> >
> > Does FreeBSD 8.0-RELEASE have an operating system limitation on the
> number
> > of USB storage devices I can connect and mount.
> >
> > Thanks.
> >
> > Patrick Collins
>

--
Patrick Collins
+61 419 712 581

David King

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Feb 19, 2010, 2:00:20 AM2/19/10

to freebsd-...@freebsd.org, Patrick Collins

> I have a requirement to connect a large number of USB bus powered external
> hard disks to a FreeBSD 8.0 system. I am talking about hundreds of them.

The USB spec itself limits to 127 devices per bus, including hubs (and including the internal hub-like device on many busses). <http://en.wikipedia.org/wiki/Universal_Serial_Bus#Overview>

> I am aware of the power and bus limitations and intend to use power hubs and

David King

unread,

Feb 20, 2010, 4:54:23 AM2/20/10

to freebsd-...@freebsd.org

> Thanks David. My question was specific to FreeBSD's limitations rather than
> USB limitiations.

You're not going to get "hundreds of them" on a single bus, whether it's FreeBSD's limitation or USB's.

>
> On 19/02/2010, David King <dk...@ketralnis.com> wrote:
>>
>>> I have a requirement to connect a large number of USB bus powered
>> external
>>> hard disks to a FreeBSD 8.0 system. I am talking about hundreds of them.
>>
>> The USB spec itself limits to 127 devices per bus, including hubs (and
>> including the internal hub-like device on many busses). <
>> http://en.wikipedia.org/wiki/Universal_Serial_Bus#Overview>
>>
>>> I am aware of the power and bus limitations and intend to use power hubs
>> and
>>> multiple server USB ports to overcome this issue. My question is this:
>>>
>>> Does FreeBSD 8.0-RELEASE have an operating system limitation on the
>> number
>>> of USB storage devices I can connect and mount.
>>>
>>> Thanks.
>>>
>>> Patrick Collins
>>
>
>
>
> --
> Patrick Collins
> +61 419 712 581

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