[dm-devel] dm-cache: clean cache resyncs to origin on every boot

[Joe Thornber]

On Tue, Oct 20, 2015 at 11:51:07AM +0500, Bogdan Vasiliev wrote:
> Hello,
> 
> I have dm-cache configuraion with SSD in writeback mode. On every boot
> an entire cache resyncs to an origin device, even if it was clean
> before on shutdown. It takes time and full bandwidth of an origin
> device.
> 
> Is there reason for this behavior or is it a bug? Why we do not trust
> a cache metadata?

If the cache is not taken down cleanly then dm-cache has to assume
every block is dirty.  Make sure your shutdown scripts are removing
the cache device.

> 
> My configuration details, if necessary:
> storage-cache_cdata:0 41943040 linear
> storage-cache_cmeta: 0 1048576 linear
> storage-data: 0 1953513472 cache 8 989/131072 128 173945/327680 610488
> 20046 574861 3817439 0 0 0 1 writeback 2 migration_threshold 2048 mq
> 10 random_threshold 4 sequential_threshold 512
> discard_promote_adjustment 1 read_promote_adjustment 4
> write_promote_adjustment 8 rw -
> storage-data_corig: 0 1953513472 linear
> 
> 
> - Bogdan
> 
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