gjournal panic 7.0-RC1

[Adam McDougall]

Ivan Voras wrote:
> Chris wrote:
>
>> Came back to see box had rebooted itself from a journal related panic.
>>
>> panic: Journal overflow (joffset=499054080000 active=499691355136 
>> inactive=4990$
>> cpuid = 0
>
> AFAIK this means that the journal is too small for your machine - try 
> doubling it until there are no more panics.
>
> If so, this is the same class of errors as ZFS (some would call it 
> "tuning errors"), only this time the space reserved for the on-disk 
> journal is too small, and the fast drives fill it up before data can 
> be transfered from the journal to the data area.
>
I did some experimentation with gjournal a few weeks ago to determine 
how I might partition
a new server, as well as how large to make my journals and where.  I did 
find that for the computers
I have tested so far, a 1 gig (default size) journal seems to be 
sufficient, but half of that or less is
asking for trouble and I could not find any workarounds to reduce the 
chances of panic when I
was already stuck with a too-small journal I created a while ago.  I 
also found the -s parameter
is vague in that it does not say what units it accepts (appears to be 
bytes) and I *could not* get it
to make a journal inside a data partition any bigger than somewhere 
around 1.7 gigs.  Some values
of -s seemed to wrap around to a smaller number, while other values gave 
errors about being too small
(when they weren't) or invalid size.  The only way I could force a 
journal size 2G or larger was
to make a separate partition for journal.  On the server I was setting 
up, I decided to make my
(journaled) data partitions da0s1d,e,f and the journals da0s2d,e,f. 

I'm just getting this out there to the list because I don't have time to 
debug it further.