Re: [atlas] USB drive more harmful than helpful?

[Michael Ionescu]

It was powered through the dedicated wall plug included with the probe. 

On May 22, 2016 12:03:39 AM GMT+02:00, Phillip Remaker <rema...@gmail.com> 
wrote:
>How was the drive powered? Dedicated supply, or a port on a router?
>
>On Sat, May 21, 2016 at 1:32 PM, Michael Ionescu <m...@ionescu.de>
>wrote:
>
>> On May 20, 2016 9:08:08 PM GMT+02:00, Phillip Remaker
><rema...@gmail.com>
>> wrote:
>> >I don't suppose RIPE buys enough USB sticks to get to talk to
>engineers
>> >at SanDISK?
>>
>> I just had a Verbatim drive originally supplied with the probe go
>> read-only, so I would say RIPE is not procuring only SanDISK.

Re: [atlas] USB drive more harmful than helpful?

[Michael Ionescu]

On May 20, 2016 3:58:06 PM GMT+02:00, Philip Homburg  
wrote:
>No, the probe actually runs from the USB stick. The internal 4MB flash
>is just enough to initialize the USB stick in a secure way. And even
>that is already tricky.

Could you perhaps write some statistical data regarding drive usage to a 
cleartext partition that could be evaluated by the hoster once the probe is in 
limbo? 
-- 

Re: [atlas] USB drive more harmful than helpful?

[Michael Ionescu]

On May 20, 2016 9:08:08 PM GMT+02:00, Phillip Remaker  wrote:
>I don't suppose RIPE buys enough USB sticks to get to talk to engineers
>at SanDISK?

I just had a Verbatim drive originally supplied with the probe go read-only, so 
I would say RIPE is not procuring only SanDISK. 

--

Re: [atlas] USB drive

[Michael Ionescu]

Hi,

I need to follow up on this once more...

The same probe, which had now been working again for several weeks after
it reformatted its drive, I have now found the drive to be read-only.
After replacing the drive with a new one, the probe is once again fine.

While troubleshooting I have found that the probe does not connect as
long as there is no functioning drive present. This makes
troubleshooting unnecessarily difficult.

I would suggest adding a couple of (SOS?) messages that would run
regardless of the presence of a drive, such as:
- detected no USB drive on bootup
- detected insertion of USB drive
- detected removal of USB drive
- detected read-only USB drive
- Starting fsck on USB drive
- Ended fsck on USB drive (possibly indicating success/failure)
- Starting to reformat USB drive
- Ended reformatting USB drive (possibly indicating success/failure)
and possibliy something that would point towards a corrupt FS - if that
is easily detectable, for instance by checking the integrity of a known
file within the FS.

Just my 2ct.
Michael


On 30.03.2016 13:50, Philip Homburg wrote:
> Hi Michael,
> [...]
> In general, the probe doesn't care what is on the USB stick. So wiping
> or formatting the stick is not needed.
>
> There is at the moment one rare exception. The filesystem can go corrupt
> to the point the fsck hangs. 
> [...]
> Philip

Re: [atlas] An article/FAQ entry about probe troubleshooting

[Michael Ionescu]

Hi,

> > I think though that there should still be more debugging info for 
> > connections.
> 
> > However, we're working on a feature to give probe hosts more guidance about
> > what's going on (and especially what's going wrong) with their probe (*),
> > and here we will make it clear if the USB replacement is in order.

In the interim, the status feature has been launched, but it doesn't help when 
the probe does not connect to the atlas server.

> Besides this, I'm sure we'll happily endorse any kind of community-written
> troubleshooting guides :)

For want of a better place I've started a troubleshooting guide on my wikipedia 
sandbox and would invite the community to help bring it to fruition. Your 
contributions are appreciated!
https://en.wikipedia.org/wiki/User:Mhi/sandbox/Troubleshooting_RIPE-Atlas_Probes

Regards,
Michael

Sent via RIPE Forum -- https://www.ripe.net/participate/mail/forum

Re: [atlas] USB drive

[Michael Ionescu]

Hi Philip,

thanks for clearing this up.

It would be really great to take some of the guesswork out of these
cases, by adding one or two checks regarding the thumbdrive and file
system status, transmitting negative results via descriptive SOS
messages and/or system status tags.

On my probe the USB problems led to a system tag "Firewall problem
suspected". This is quite misleading. After your description I would
suspect the FS issue impeded the probe so deeply that it wasn't able to
call home at all anymore.

To my understanding, probes should be fire-and-forget as much as
possible, so I think any fsck should be run in a way that would not
impede an otherwise functioning probe.

Michael



On 30.03.2016 13:50, Philip Homburg wrote:
> Hi Michael,
> [...]
> In general, the probe doesn't care what is on the USB stick. So wiping
> or formatting the stick is not needed.
> 
> There is at the moment one rare exception. The filesystem can go corrupt
> to the point the fsck hangs. 
> [...]
> Philip