On Wed, Feb 01, 2012 at 07:23:45PM -0800, Marc MERLIN wrote: > On Wed, Feb 01, 2012 at 12:56:24PM -0500, Chris Mason wrote: > > > Second, I was wondering if anyone is running btrfs over dmcrypt on an SSD > > > and what the performance is like with write cache turned off (I'm actually > > > not too sure what the impact is for SSDs considering that writing to flash > > > can actually be slower than writing to a hard drive). > > > > Performance without the cache on is going to vary wildly from one SSD to > > another. Some really need it to give them nice fat writes while others > > do better on smaller writes. It's best to just test yours and see. > > > > With a 3.2 kernel (it really must be 3.2 or higher), both btrfs and dm > > are doing the right thing for barriers. > > Thanks for the answer. > Can you confirm that I still must disable write cache on the SSD to avoid > corruption with btrfs on top of dmcrypt, or is there a chance that it just > works now?
No, with 3.2 or higher it is expected to work. dm-crypt is doing the barriers correctly and as of 3.2 btrfs is sending them down correctly. -chris -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
