"System has insufficient buffers to rebalance the tree." after upgrade to 3.8.1

[Justin Sherrill]

I haven't done this, but: hammer rebalance can be given a percentage
amount.  It defaults to 85%, so you could start small and see how well
it works up -

hammer rebalance 50
hammer rebalance 60
etc.

On Fri, Jun 27, 2014 at 4:03 AM, Marco Righele <marco at righele.it> wrote:
> Greetings,
>
> I have a small system that I recently upgraded from 3.6 to 3.8.1.
> After the upgrade, the nightly jobs will spew
>
>     hammer: System has insufficient buffers to rebalance the tree. nbuf <
> 3969
>
> on the log while trying to do hammer rebalance.
>
> If I try hammer rebalance on any pfs from the command line I will get
>
>     Rebalance / failed: No space left on device
>
> even though the system has about 10% of free space (13GB out of 140GB).
> Normal operation
> doesn't seem to be affected.
>
> hammer(5) says:
>  Rebalancing a HAMMER PFS uses quite a bit of memory and can't be done on
>      low memory systems.  It has been reported to fail on 512MB systems.
>      Rebalancing isn't critical for HAMMER file system operation; it is done
>      by hammer rebalance, often as part of hammer cleanup.
>
> The machine has 2GB of RAM, so unless the requirement changed it shouldn't
> be a an issue of not having enough memory.
>
> Is it something I should worry about ?
>
> Marco
>
>
>