Panic on external HD disconnection
smithi at nimnet.asn.au
Fri Jun 9 13:37:08 UTC 2017
In freebsd-questions Digest, Vol 679, Issue 5, Message: 4
On Fri, 9 Jun 2017 09:35:02 +0200 Andrea Venturoli <ml at netfence.it> wrote:
> On 06/08/17 20:47, Polytropon wrote:
> > So the disk was mounted at that specific point in time?
> Yes, as I said I was taking a backup, so that disk was mounted and was
> being written to.
You said "external UFS HD" but not how attached. Can I assume USB?
> > Partially understandable. The system will somehow react
> > to a mass media device surprisingly removed when it is
> > writing to it...
> Yes, *partially* understandable.
> I just like to know to what extent that "partially" goes.
> If I am to expect a full panic, it's ok.
Assuming USB attached, all the more likely to panic. Even if you're not
writing to it at the time - mounting noatime can help - external USB
mounts never seem to survive disconnect / reconnect, even when they may
initially appear to - e.g. ls /mnt/somedir may show cached contents, but
attempts to read files from there (or write, no doubt) will fail.
That said, I haven't had a panic from bumping a memstick since 7.x or
so, but then I likely wasn't writing to it at the time. umount, a
cautionary fsck, then remounting haven't failed me since FreeBSD 9.
> If, somehow, I could get a partial failure, then something is wrong in
> my setup and I'll have to investigate.
Again assuming USB, you could ask in freebsd-usb@ re the current status
for that scenario. Yes _in theory_ it shouldn't panic the whole system.
Hope fsck gave you your disk back clean. Did /var/log/messages from
before the panic indicate anything related?
cheers, Ian (please cc me, I take the -digest)
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