Re: Cache tier READ_FORWARD transition

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Mon, 7 Jul 2014, Luis Pabon wrote:
> Hi all,
>     I am working on OSDMonitor.cc:5325 and wanted to confirm the following
> read_forward cache tier transition:
> 
>     readforward -> forward || writeback || (any && num_objects_dirty == 0)
>     forward -> writeback || readforward || (any && num_objects_dirty == 0)
>     writeback -> readforward || forward
> 
> Is this the correct cache tier state transition?

That looks right to me.

By the way, I had a thought after we spoke that we probably want something 
that is somewhere inbetween the current writeback behavior (promote on 
first read) and the read_forward behavior (never promote on read).  I 
suspect a good all-around policy is something like promote on second read?  
This should probably be rolled into the writeback mode as a tunable...

sage


--
To unsubscribe from this list: send the line "unsubscribe ceph-devel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




[Index of Archives]     [CEPH Users]     [Ceph Large]     [Information on CEPH]     [Linux BTRFS]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux