System has insufficient buffers to rebalance the tree

Stephane Russell srussell at
Sun May 15 06:50:17 PDT 2011

I have the same problem, I've just converted my data volume to a HAMMER
file system on my server. I receive this message:

«hammer: System has insufficient buffers to rebalance the tree.  nbuf <

I have 512MB of SDRAM on it. I guess it's time for me to upgrade this :-)


Le 2011-01-31 16:17, Matthew Dillon a écrit :
> :On Sunday 30 January 2011 22:43:01 Matthew Dillon wrote:
> :> :I still get this warning. Is it ever going to be fixed?
> :> :
> :> :Pierre
> :>
> :>     I could remove the kprintf I guess and have it just reported by
> :>     hammer cleanup.
> :
> :Is the number of buffers something I can change, or is it determined by the 
> :kernel based on memory size?
> :
> :Pierre
>    It's based on memory size and while it is possible to change it the
>    problem is that your system doesn't have enough memory for what the
>    hammer rebalance code really needs to operate.
>    Part of this is that the rebalance algorithm simply requires a huge number
>    of concurrent buffers.  Ultimately the fix would be to change the algorithm
>    but it isn't easy to reformulate and I don't really want to break it open
>    because one mistake in that code could blow up the filesystem.
> 					-Matt
> 					Matthew Dillon 
> 					<dillon at>

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