[dm-devel] Shared snapshots

Pasi Kärkkäinen pasik at iki.fi
Thu Jan 7 08:42:55 UTC 2010


On Wed, Jan 06, 2010 at 09:38:00AM -0500, Mikulas Patocka wrote:
> Hi
> 
> I uploaded new code for shared snapshots at
> http://people.redhat.com/mpatocka/patches/kernel/new-snapshots/devel/
> 
> Changes:
> - two queues, one for reads and one for writes, to improve read latency 
> when the device is write-congested
> - limit number of reallocations in flight (VM subsystem sends all writes 
> at once and without limit it creates big lags).
> - fixed one place where it didn't handle on-disk errors
> - simplified bitmap creation, removed some unneeded code
> - new macro for error reporting, as suggested by Zdenek
> - some comments added
> - DM_ prefix added to some macros
> 
> Userspace for lvm 2.02.53 is at
> http://people.redhat.com/mpatocka/patches/userspace/new-snapshots/lvm-2.02.54/
> 
> Please, someone, do offensive testing with this --- i.e. apply the 
> patches, try it, and try all possible lvm commands with it, try to stress 
> and crash it in various ways, etc. If we wait with testing until Alasdair 
> reads the code, it won't get much testing...
> 

Sorry for a stupid question, but what does "shared" mean? Support for CLVM?

-- Pasi




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